Ureas Thioureas in detail for study

7/28/2019 Ureas Thioureas in detail for study

1/54

C H A P T E R 1 2Carboxamides , Ureas ,Th ioureas , Imidazo l id inones ,Caffeine, Isocaffeine, Uraci ls ,Imides , Hydanto ins , ands-T riazine ( 1H ,3H ,5H )-T rionesDilut ion Studies of N-alkylacetamide andN-alkylachlorocetamide 216Trans and /o r Ci s Secondary Amides 217N - H I n t e ns i ty 2 1 9Acetani l ides 222N-alkyl Benz amides 223N-alkyl M ethyl Carb anates 223N,N '-Dia lky l Oxam ides and N,N '-Diary l Oxam ide 223Dimethy lace tamide and Tet raa lky lu rea 2241,1,3,3-Tetramethylurea vs 1 ,3-Dimethyl-2-imidazol idinone 225Caffeine, Isocaffeine, 1 ,3 ,5-Trimethyluraci l , 1 ,3 ,6-Trimethyluraci l , and1,3-dimethyl-2,4-(1 H,3H) quinazol ined ione 226Imides 2274-Brom obutylphthal im ide in Solut ion 229Hydan to ins 229Trial lyl - l,3 ,5-t r iazine-2,4,6-(1H,3H5H ) t r ione 229References 230FiguresFigure 12-1 232 (216) Figure 12-7 238 (226)Figure 12-2 233 (217) Figure 12-8 239 (230)Figure 12-3 234 (222) Figure 12-9 239 (230)Figure 12-4 235 (224) Figure 12-10 239 (230)Figure 12-5 236 (226) Figure 12-11 240 (228)Figure 12-6 237 (226)TablesTable 12-1 241 (215, 217) Table 12-1c 243 (217)Table 12-1a 242 (216) Table 12-2 244 (217, 219)Table 12-1b 242 (216) Table 12-2a 246 (219)

213


2/54

214 Carboxamides, Ureas, Thioureas, lm idazolidinones, Caffeine, Isocaffeine, Uracils, Imides, etc.Table 12-3 248 (220) Table 12-11 257 (225)Table 12-4 249 (220) Table 12-12 258 (225)Table 12-4a 249 (220) Table 12-13 259 (226)Table 12-5 250 (221) Table 12-14 260 (226)Table 12-5a 251 (221 ) Table 12-15 261 (227 )Table 12-6 252 (221) Table 12-16 262 (227)Table 12-7 253 (222) Table 12-17 264 (229)Table 12-8 254 (223) Table 12-18 265 (229)Table 12-9 255 (223) Table 12-19 266 (229)Table 12-10 256 (224) Table 12-20 266 (230)*Numbers in parentheses indicate in-text page reference.

The re a re s e ve ra l fo rms o f c a rboxa m i de s , a n d t he y a re s e pa ra t e d i n t o t h re e c l a sse s: p r i ma ry ,s e c o nd a r y , a n d t er ti ar y . P r i m a r y c a r b o x a m i d e s a ls o e x i s t i n t h r e e f o r m s : H ( C = O ) N H 2 ,R ( C = O N H 2, a n d ~ b ( C = O ) N H 2. S e c o n d a r y c a r b o x a m i d e s e x i st i n t h e f o l lo w i n g f o r m s :H ( C = O ) N H R , R ( C = O ) N H R ' , R ( C = O ) N H ~ b , ~ b ( C = O ) N H R , ~ b ( C = O ) N H ~ ,

(CH 2)n

H

N and~ o

T e r t i a r y c a r b o x a m i d e s c a n h a v e t h e b a s i c s t r u c t u r e s a s d e n o t e d f o r t h e s e c o n d a r y c a r b o x a m i d e swi t h t he r e p l a c e m e n t o f t he NH p ro t on wi t h R o r ~b. Ea c h o f the se fo rm s y i e l d s it s ownc ha ra c t e r i s t i c g roup f r e que nc i e s , a nd e a c h wi l l be d i s c us se d i n wha t fo l l ows .Ta b l e 12 .1 show s a c om pa r i s on o f p r i ma ry , s ec onda ry , a nd t e r t i a ry a mi de s i n va r i ous phys i c a lpha se s .

I n t h e c as e o f th e p r i m a r y a m i d e s t h e v a s y m . N H 2 , v s y m . N H 2 , a n d v C = O m o d e s o c c u r a th i g h e r f r e q u e n c y i n t h e v a p o r p h a s e t h a n i n t h e n e a t p h a s e . I t i s n o t e w o r t h y t h a t v C - - O f o r~ b ( C = O ) N H 2 ( 1 7 1 9 - 1 7 3 1 c m - 1 ) o c c u r s a t lo w e r f r e q u en c y t h a n v C = O f o r R ( C = O ) N H 2 ( 1 7 3 2 -1 7 8 0 c m - 1 ) d u e t o c o n j u g a t i o n o f t h e c a r b o n y l g r o u p w i t h t h e Ir s y s t e m o f t h e p h e n y l g r o u p ( 1 ) .I n t h e c a se o f R ( C = O ) N H 2 , t h e h i g h f r e q u e n c y v C - - O m o d e a t 1 7 8 0 c m - 1 i s t h e r e s u l t o f t h ei n d u c t i v e e ff ec t o f th e C F 3 g r o u p f o r C F 3 ( C = O ) N H 2, a n d t h e l o w f r e q u e n c y i s t h e r e s u l t o f t h ei nduc t i v e e f f e ct o f t he a l ky l g roup (C13H26) fo r R (C =O )N H 2 (1 ) . Ev i de nc e i s a l so p re se n t e d t ha ti n t h e v a p o r p h a s e t h e 0 r a n a l o g s a r e i n a n i n t r a m o l e c u l a r l y h y d r o g e n - b o n d e d t r a n sc o n f i g u r a t i o n ( 1 ) .

o

o i i Z "X " 9 9 H


3/54

Variables in Data Interpretation 215F o r e x a m p l e , i n t h e v a p o r p h a s e v C = O o c c u r s a t 1 7 4 0, 1 7 4 9 , a n d 1 7 8 0 c m - 1 f o r a c e t a m i d e ,f l u o r o a c e t a mi d e , a n d t r i f l u o r o a c e t a mi d e , r e s p e c t iv e l y , w h i l e v a s y m. N H 2 o c c u r s a t 3 5 6 5 , 3 5 5 2 ,a n d 3 5 6 0 c m - 1 , a n d v s y m . N H 2 o c c u r s a t 3 4 4 2 , 3 4 4 4 , a n d 3 4 3 9 c m - 1 , r e s p e c t i v e l y ( 1 ).S u b s t i t u ti o n o f t h e f ir st F a t o m o n t h e a - c a r b o n a t o m r a i s e s v C = O b y 9 c m - 1 w h i l e s u b s t i t u t i o no f th r e e F a t o m s r a is e s v C = O b y 4 0 c m - 1 . T h e r e f o r e , v C = O i s r a i s e d 3 1 c m - 1 f o r t h es u b s t i t u t i o n o f t h e s e c o n d a n d t h i r d F a t o m s , o r 1 5 . 5 c m - 1 p e r F a t o m . T h e s e d a t a i n d i c a t et h a t t h e a d d i t i o n o f t h e f ir st a -f l u o r i n e a t o m o n t h e a - c a r b o n a t o m o f a c e t a m i d e f o r m s a ni n t ra m o l e c u l a r h y d r o g e n a t o m a s d e p i c te d h e r e , a n d l o w e r s v C = O b y ~ 6 . 5 c m - 1. T h i si n t r a m o l e c u l a r N - H . . . F b o n d i s p r e s e n t i n t h e F , F ~ a n d F 3 a n a l o gs , o r o t h e r w i s e e a c hv C = O m o d e w o u l d b e ~ 6 . 5 c m - 1 h i g h e r i n f r e q ue n c y ( 1 ) .

C o m p o u n d s s u c h a s 2 - a m i n o b e n z a m i d e a n d 2 - m e t h o x y b e n z a m i d e i n th e v a po r p h a s e e x h ib i tv C = O a t 1 6 9 8 a n d 1 7 0 9 c m - 1 , r es p e ct iv e ly , w h i l e b e n z a m i d e a n d 3 - X a n d 4 - X b e n z a m i d e se x h ib i t v C = O i n t he r a n g e 1 7 1 9 - 1 7 3 1 c m - 1 . I n th e c a s e of 2 - a m i n o b e n z a m i d e a n d 2 -m e t h y o x y b e n z a m i d e , t h e a m i d e N H 2 p r o t o n is i n t ra m o l e c u l a r ly h y d r o g e n b o n d e d t o t h eo x y g e n a t o m o f t h e C H 3 0 g r o u p o r t h e n i t r o g e n a t o m o f t h e a m i n o N H 2 g r o u p .

OC H 3v H

0 H H H

I n t h e c a s e o f t h e 2 - a m i n o a n a l o g , t h e v a s y m . N H 2 a n d v s y m. N H 2 f o r t h e a m i n o N H 2 g r o u po c c u r a t 3 5 1 1 a n d v 3 3 7 0 c m - 1 , r e sp e c ti v el y . T h e f r e q u e n c y s e p a r a t i o n o f 1 41 c m - 1 i s e v i d e n c et h a t a n a n i l in e t y p e N H 2 g r o u p i s i n t r a m o l e c u l a r l y h y d r o g e n b o n d e d ( 1 ). I n t h e c a s e o f th e 2 -m e t h o x y a n a l o g, v a s ym . N H 2 a n d v s y m . N H 2 f o r t h e a m i d e g r o u p a r e a s s i g n e d a t 3 5 4 0 a n d3 4 2 0 c m - 1 , w h i c h i s l o w e r t h a n o t h e r m e m b e r s i n t h e o t h e r b e n z a m i d e s s t u d i e d i n t h e v a p o rp h a s e .T h e 2 - h y d r o x y b e n z a m i d e i n t h e v a p o r p h a s e i s a s p e c i a l c a s e i n t h a t t h e O H p r o t o n i si n t r a m o l e c u l a r l y h y d r o g e n b o n d e d t o t h e c a r b o n y l g r o u p .

0 / H " " ' 0

I n t h i s c a s e v C = O - . . H O o c c u r s a t 1 6 7 9 c m - 1 , a n d v O H - . . N a t 3 2 7 0 c m - 1 ( 1 ).I n t h e v a p o r p h a s e , a n o t h e r u n i q u e c a s e i s 2 , 6 - d i c h l o r o b e n z a m i d e , b e c a u s e v C = O o c c u r s a t

1 7 35 c m - 1 . T h e h i g h v C = O f r e q u e n c y ( 1 7 3 1 c m - 1 ) l i s t e d i n T a b l e 1 2 . 1 i s f o r 3 , 5 - d i n i t r o b e n z a -m i d e . I n t h e c a s e o f t h e 2 ,6 -C 12 a n a l o g , t h e p h e n y l a n d ( C = O ) N H 2 g r o u p s a r e n o t c o p l a n a r , a n dt h e r e a s o n t h a t v C = O o c c u r s a t s u c h a r e l a t i v e l y h i g h f r e q u e n c y i s t h a t t h e s e t w o g r o u p s a r e n ol o n g e r in r e s o n a n c e . T h e t w o g r o u p s a r e c o p l a n a r i n t he c a s e o f 3 , 5 - d i n i t r o b e n z a m i d e , b u t t h eh i g h H a m m e t t ~ rm v a l u e f o r t h e t w o N O 2 g r o u p s c o n t r i b u t e s t o t h e r e l a ti v e ly h i g h v C = Of r e q u e n c y .


4/54

216 Carboxamides , Ureas , Thioureas , Imidazol idinones , Caffe ine , Isocaffe ine , Uraci ls , Imides , e tc .M e t h y l m e t h a c r y l a m i d e ( v C = O , 1 7 21 c m - 1 , v a p o r ) e x h i b i t s v C = O a t l o w e r f r e q u e n c y t h a n

ac r y l am id e ( v C = O , 1 7 31 cm - 1 , v ap o r ) d u e to t h e in d u c t iv e e l ec t r o n d o n a t io n o f t h e m e th y lg r o u p t o t h e C = O g r o u p ( 1 ) .

D I L U T I O N S T U D I E S O F N - A L K Y L A C E T A M I D E A N DN - A L K Y L C H L O R O A C E T A M I D ET ab le 1 2 .1a li s ts t h e N - H s t r e t ch in g f r eq u en c ie s f o r N- m e th y l a ce t am id e in m o l /1 co n cen t r a -t ions rang i ng f rom 1 .37 x 10 -3 to 1 .37. The v N H m o d e d ec r ea se s f r o m 3 4 7 6 to 3 4 7 1 c m - 1 , a n dth e ab so r b an ce in c r ea se s f r o m 0 .2 to 8 .9 . A t 1 .3 7 x 1 0 - 3 m o l /1 n o in t e r m o lecu la r a s so c i a t io n i sn o t e d b e t w e e n C - - O . . . H N . H o w e v e r , t h e % v N - H . . . C = O i n c r ea se s s t e ad i ly t o ~9 5 % a t1 . 3 7 m o l /1 . I n t h e c a se o f N - m e t h y l c h l o r o a c e t a m i d e i n m o l e / l i t e r c o n c e n t r a t i o n s r a n g i n gf rom 9 .21 x 10 -3 to 9 .21 , the v N - H f r eq u en cy r an g e o f fr o m 3 4 5 0 - 3 4 4 8 cm - 1 in a d ec r ea s in go r d e r w i th in c r ea s in g co n cen t r a t io n wh i l e ab so r b an ce in c r ea se s f r o m 0 .2 to 5 . I n t h i s c a se , t h ei n t e r m o l e c u l a r h y d r o g e n b o n d i n g b e t w e e n N - H . - - O - - C v a r ie s fr o m 1 - 6 4 % ( 5) . I t h a s b e e nsh o wn th a t t h e N- a lk y l ch lo r o ace t am id e an d a - h a lo - p - x - ace t an i l i d e s i n d i lu t e so lu t io n ex i s t i n ani n t r a m o l e c u l a r h y d r o g e n b o n d e d - f o r m ( 6 , 7 ) .

O

i . . j RFig u r e 1 2 .1 sh o ws p lo t s o f t h e co n cen t r a t io n v s t h e ab so r p t io n m ax im a a t e ach o f t h e

v N - H . . . O - - C f r eq u e n c ie s s h o w n i n T ab le 1 2. 1a . A t l o w c o n c e n t r a t i o n s ( b e l o w 0 . 0 1 M f orN - m e t h y l a c e t a m i d e a n d b e l o w 0 . 2 M f o r N - m e t h y l c h l o r o a c e t a m i d e ) t h e f r e q u e n c y o fa b s o r p t i o n m a x i m u m o f t h e i n t e r m o l e c u l a r v N - H . . . O = C b a n d i s i n d e p e n d e n t o f c o n c e n t r a -t io n , i n d i c a ti n g t h a t i n a d d i t io n t o a m o n o m e r o n l y o n e N - H . . . O = C i n t e r m o l e c u l a r s p e c ie s i sp r e sen t , p r e su m ab ly a d im er ( 5 ) . A t h ig h e r co n cen t r a t io n s th e f r eq u e n cy o f ab so r p t io n d ec r ea se sr ap id ly wi th in c r ea s in g co n ce n t r a t io n . I n t h e ca se o f N- m e th y l a ce t am id e a t co n ce n t r a t io n ab o v e~ 0 . 3 M t h e v N - H . . . O - - C f r eq u en cy i s i n d e p en d en t o f co n c en t r a t io n an d th e av e rag e s ize o f t h ei n t e r m o l e c u l a r ( N - H . . - O = C ) , , c o m p l e x i s a b o u t s e v e n o r m o r e . T h e N - m e t h y l c h l o r o a c e t a m i d eis d i f fe ren t , because in sa tu ra ted C C 1 4 so lu t io n o n ly o n e - th i r d o f t h e m o lecu le s ex i s t i na n i n t e rm o l e c u l a r h y d r o g e n - b o n d e d f o r m ( N - H . . . O = C ) n. A t c o n c e n t ra t i o n s o f l es s th a n0 . 2 M , N - m e t h y l c h l o r o a c e t a m i d e m o l e c u l e s e x i s t i n t h e i n t r a m o l e c u l a r h y d r o g e n - b o n d e df o r m ( NH. . .C1 ) ( 5 ) .

T ab le 1 2 .1b l i s ts am id e I , I I, an d I I I f r eq u en c ie s f o r N- m e th y l a ce t am id e in v a r io u s m o le / l i t e rin Br 3 CH so lu t io n . Br o m o f o r m was u sed in t h i s c a se in s t ead o f ch lo r o f o r m in o r d e r t o m easu r eth e am id e II f r eq u en c ie s . T h e d a t a sh o w th a t a s t h e co n cen t r a t io n in c r ea se s v N - H in c r ea se sf r o m 3 4 5 6 to 3 4 5 7 c m - 1 wh i l e am id e I I ( o r N - H b en d in g ) i n c r ea se s f r o m 1 5 31 to 1 53 7 c m - 1 in0 .6 8 5 m o l /1 . A t 0 .6 8 5 m o l /1 co n cen t r a t io n v N - H . . . O = C b o n d in g i s o b se r v ed a t 3 3 2 5 c m - 1 a n dam id e I I i s n o ted a t 1 5 6 0 c m - 1 . W ith in c r ea s in g co n cen t r a t io n ( 2 .7 4 m o l /1 ) am id e I I i s o b se r v edat 1563 c m - 1 , v N - H ( O = C a t 3 30 5 c m - 1 . W i t h i n c r e a s i n g c o n c e n t r a t i o n ( 2 .7 4 m o l / 1 ) v N - H iso b s e rv e d a t 1 5 6 3 c m - 1 a n d v N - H . . . O - - C a t 3 3 0 5 c m - 1. A s t h e v C = O a n d v C - - O . . - H N


5/54

V a r i a b l e s i n D a t a I n t e r p r e t a t i o n 217f r eq u en cie s d ec r ea se f r o m 1 6 6 8 - 1 6 4 9 cm - 1 th e am id e II ( o r N - H b en d in g ) f r eq u en c ies i n c r ea sef r o m 1 5 3 1 - 1 5 6 3 cm - 1 wi th in c r ea s in g co n cen t r a t io n . T h e am id e I I I m o d e i s ap p a r en t lyin d ep e n d en t o f co n cen t r a t io n , a s it o ccu r s n ea r 1 2 7 8 - 1 2 7 9 c m - 1 .

Table 12 .1c l i s ts IR da ta fo r the f ir s t over to ne of am ide I I fo r N-m ethy l ace ta mid e an d N -m e th y l ch lo r o ace t am id e in v a r y in g m o le / l i t e r co n cen t r a t io n s in CC14 so lu t io n . T h ese d a t a sh o wth a t t h e b an d in t en s i ty o f t h e f ir s t o v e r to n e o f am id e I I ( o r N - H b en d in g ) i n c r ea se s a s t h em o le / l i t e r co n cen t r a t io n i s i n c r ea sed ( 0 .6 t o 2 8 x 1 08 f o r N- m e th y l a ce t am id e an d 1 .7 to15 x 108 for N-methy l ch loroace tamide) . As the v N - H . . . O = C f r eq u en c ies d ec r ea se th e am id e I If r eq u en cy in c rea se s w i th an in c r ea se in co n cen t r a t io n . T h u s , t h e f i rs t o v e r to n e o f am id e I I sh o u ldin c r ea se in f r eq u en cy wi th an in c r ea se in t h e m o le / l i t e r co n cen t r a t io n , an d th e v N - H . . . O = Cf r eq u en cy sh o ws d ec r ea se s in f r eq u en cy . T h u s , t h e am o u n t o f Fe r m i r e so n an ce in t e r ac t io nb e tween th e se two m o d es sh o ws d ec r ea se , b ecau se th e two m o d es a r e m o v in g in o p p o s i t ed i rec t ions . As a cons eque nce of th is behav ior , th is abso rp t ion has no s ign i f ican t in ten si ty in thoseam id es , wh ich a r e o n ly s l i g h tly a s so c ia t ed . O f th e c o m p o u n d s s tu d ied , o n ly C1 , Br, an d CF 3N- a lk y l a ce tam id e ex h ib i t ed s ig n i fi c an t ab so r p t io n in t h i s r eg io n o f t h e sp e c t r u m ( 5 ).

T R A N S A N D / O R C I S S E C O N D A R Y A M I D E SI n th e ca se o f 4 - , 5 -, 6- , an d 7 - m em b er ed l a c t am s th e N - H g r o u p i s c i s t o t h e ca r b o n y l g r o u p .T ab le 1 2 .1 sh o ws th a t v N- H f o r t h e 5 - , 6 - , 7 - m em b er ed l a c t am s o ccu r s a t 3 4 7 8 , 3 4 3 8 , an d3 4 4 2 cm - 1 , r e sp ec tiv ely . It h a s b een r ep o r t ed th a t a co m p o u n d su ch a s N- m e th y l a ce t am id eex is ts 95% in the t rans fo rm and 5% in the c is fo rm.

o\ " \

N ~ R ' N ~ H/ . , /t r i m s

Mo r eo v e r , N- t e r t - b u ty l p h en y lace t am id e was r ep o r t ed to ex i s t a s 3 0 % in th e t r an s f o r m an d 7 0 %in the c is fo r m . T h e p o ss ib i l i ty o f Fe r m i r e so n an ce b e tw een v N - H an d th e f i r st o v e r to n e o fv C = O w a s e x c l u d e d o n t he g r o u n d s t h a t th e a n h a r m o n i c i t y f a c t o r w o u l d b e m u c h t o o n e g a ti v e(8,9) .

F ig u r e 1 2 .2 sh o ws I R sp ec t r a o f N- m e th y l a ce t am id e , N- e th y l a ce t am id e , N - i so p r o p y lace t am id e , N- t e r t - b u ty l a ce t am id e , an d ace t an i l i d e in CC1 4 so lu t io n in t h e r eg io n 3 8 0 0 -3 3 0 0 cm - 1 . I n t h e se case s , th e v N - H s t r e t ch m o d e d ec r ea se s i n f r eq u en cy in t h e o r d e r 3 4 7 9 ,3 4 6 2 , 3 4 5 1 , 3 4 5 3 , an d 3 4 4 9 cm - 1 , r e spec t iv e ly, an d th e v C = O f r eq u en cy in c r ea se s i n t h e o r d e r :1 6 8 6, 1 6 8 6, 1 6 8 7, 1 6 8 6, an d 1 7 0 8 cm - 1 , r e spec tiv e ly . T h e w eak b a n d s in t h e r an g e 3 3 5 0 -3 4 0 0 cm - 1 a r e r ead i ly a s s ig n ed a s 2 ( v C = O ) ( 6 ). T h e d i f f e r en ce b e tween th e N- m e th y l a ce t am id ev N- H f r eq u en cy an d th o se f o r t h e N- e th y l , N- i so p r o p y l , N- t e r t - b u ty l , an d N- p h en y l an a lo g s i s17, 28 , 26 , and 30 cm -1 , respec t ive ly . In add i t ion , there i s no o the r ban d p rese n t to ind ic a te thep r e sen ce o f an o th e r r o t a t io n a l co n f o r m er , an d th e v N - H f r eq u en cy d ec r ea se fo l lo ws c lo sely th ein d u c t iv e co n t r ib u t io n o f t h e N- a lk y l g r o u p to t h e ca r b o n y l g r o u p . T h e r e f o r e , i t was co n c lu d edth a t t h e N- a lk y l a ce t am id es ex i s t i n t h e t r an s co n f ig u r a t io n in d i lu t e CC1 4 so lu t io n . T h e r e i s n oposi t ive ev idence fo r the ex is tence o f the c is conformer (6 ) .

T ab le 1 2 .2 l i s t s I R d a t a an d a ss ig n m en t s f o r N- a lk y l a ce t am id es an d N- a lk y l - a - su b s t i t u t edace t am id es .


6/54

218 Carboxamides, Ureas, Thioureas, Imidazolidinones, Caffeine, Isocaffeine, Uracils, Imides, etc.The da ta on the N-a lky l ace tamides s howed tha t v -H i s s ens i t ive to the na tu re o f the N-a lky l

g roup . Thus , when compar ing da ta fo r N-a lky l a -ha loace tamides vs thos e fo r N-a lky l ace tamidesi t i s neces s a ry to compare da ta fo r the s ame N-a lky l ana logs .

C o m p a r i s o n o f t h e v N - H f r e qu e n c i es f o r N - b u t y l a c e t a m i d e ( 3 4 6 0 c m - 1 ) v s N - b u t y l a -ch lo roace tam ide (3433 cm -1) , N- i s opro py l ace tamide (3451 cm -1 ) v s N- i s opropy l a - ch lo roace-tamide (3429 cm -1) , an d N- te r t -bu ty l ace tam ide (3453 cm -1 ) v s N- te r t -bu ty l a - ch lo roace ta mide(3421 cm -1 ) s hows tha t v N - H occur s a t lower f r equency b y 22 -32 cm -1 in the cas e o f the a -c h l o ro a n a l og . C o m p a r i s o n o f t he v C = O f r eq u e n c ie s f o r N - b u t y l a c e ta m i d e ( 1 6 8 8 c m - 1 ) v s N -b u t y l a - c h l o ro a c e t a m i d e ( 1 6 8 4 c m - 1 ) , N - i s o p r o p y l a c e t am i d e ( 1 6 8 7 c m - 1 ) v s N - i so p r o p y l a -c h l o r o a c e ta m i d e ( 1 6 8 2 c m - 1 ) , a n d N - t e r t -b u t y l a c e t am i d e ( 1 6 8 8 c m - 1 ) v s N - t e r t - b u ty l a -c h l o r o a c e ta m i d e ( 1 6 8 4 c m - 1 ) s h o w s t h a t v C = O d e c re a s es i n f r e q u e n c y b y 4 to 5 c m - 1 .

C o m p a r i s o n o f th e v N - H f r equenc ies fo r N-bu ty l a - ch lo roace tam ide (3433 cm -1 ) v s N-bu ty la , - d ic h l o r o a c e ta m i d e ( 3 4 3 9 c m - 1 ) , i s o p r o p y l a - c h lo r o a c e t a m i d e ( 3 4 3 0 c m - 1 ) v s i s o p r o p y l a - a -d i c h l o r o ac e t a m i d e ( 3 4 3 9 c m - 1 ) , a n d t e r t- b u t y l a - c h l o r o a c e ta m i d e ( 3 4 21 c m - 1 ) v s N - t e r t - b u t y la , a - d i c h l o ro a c e t a m i d e ( 3 4 3 5 c m - 1 ) s h o w s t h a t v N - H inc reas es in f r equency by 6 to 14 cm -1wi th the add i t ion o f the s econd a -ch lo ro a tom .

C o m p a r i s o n o f th e v C = O f r eq u e n c ie s f o r N - b u t y l c h lo r o a c e t a m i d e ( 1 6 8 4 c m - 1 ) v s N - b u t y la , a - d i c h l o ro a c e t a m i d e ( 1 7 0 5 c m - 1 ) , N - i s o p r o p y l a - c h lo r o a c e t a m i d e ( 1 6 8 2 c m - 1 ) v s N - i s o p r o p y la , a - d i c h l o ro a c e t a m i d e ( 1 7 0 3 c m - 1 ) , a n d N - t e r t -b u t y l a - c h l o r o a c e t a m i d e ( 1 6 8 4 c m - 1 ) v s N - t e r t-b u t y l a ,a - d i c h l o r o a c e t a m i d e ( 1 7 0 2 c m - 1 ) s h o w s t h a t v C - O i n c re a s e s in f r e q u e n c y by 1 8 -22 cm -1 w i th the add i t ion o f the s ec ond ch lo r ine a tom.

C o m p a r i s o n o f t h e v N - H f r equenc ies fo r N-bu ty l a , a -d ich lo ro ace tam ide (3439 cm -1 ) v s N-bu ty l a , a , a - t r i ch lo roace tam ide (3445 cm-1) , N- i s opropy l a , a -d ich lo roa ce tam ide (3430 cm -1 ) v sN - i s o p r o p y l a , a , a - t r ic h l o r o a c e ta m i d e ( 3 4 3 9 c m - 1 ) , a n d N - t e r t - b u ty l a , a - d i c h l o r o a c e t a m i d e(3427 cm -1 ) v s N- te r t -bu ty l a , a , a - t r i ch lo roace tam ide (3435 cm -1 ) s how s tha t v N - H increasesin f r equency by ano the r 6 to 9 cm -1 w i th the add i t ion o f the th i rd ch lo r ine a tom .

C o m p a r i s o n o f t h e v C = O f r eq u e n c ie s f o r N - b u t y l a , a - d ic h l o r o a c e t a m i d e ( 1 7 0 5 c m - 1 ) v s N -bu ty l a , a , a - t r i ch lo roace tam ide ( 1726 cm -1 ) , N - i s op ropy l a , a , -d ich lo roace tam ide ( 1703 cm -1 ) v sN - i s o p r o p y l a , a , a - d i c h l o r o a c e ta m i d e ( 1 7 2 5 c m - 1 ) , a n d N - t e r t - b u ty l a , a - d i c h l o r o a c e t a m i d e( 1 7 0 2 c m - 1 ) v s N - t e r t - b u ty l a , a , a - t r ic h l o r o a c e t a m i d e ( 1 7 2 5 c m - 1 ) s h o w s t h a t v C = O i n c re a s esin f r equency by ano the r 21 to 23 cm -1 w i th the add i t ion o f the th i rd ch lo r ine a tom .

Thes e compar i s ons s how tha t w i th the add i t ion o f the f i r s t a - ch lo r ine a tom on N-a lky l ace ta -mide the v N - H f r equenc ies dec reas e by 22 -32 cm -1 and the vC =O f r equenc ies inc rease by 4 to5 cm -1 . Wi th the add i t ion o f the s eco nd a -ch lo r ine a tom the v N - H f r equenc ies inc reas e by 6to 14 cm -1 an d the vC =O f r equenc ies inc reas e by 18 -2 2 cm -1 . Wi th the add i t ion o f the th i rd a -ch lo r ine a tom v N - H i n c re a s e b y a n o t h e r 6 - 9 c m - 1 a n d v C = O i n c re a s e b y a n o t h e r 2 1 - 2 3 c m - 1 .

There i s on ly one exp lana t ion fo r the behav io r o f the v N - H a n d v C = O d a t a f o r t h e N - a l k y lch lo roace tam ide ana logs. Upo n add i t ion o f the f ir s t a - ch lo r ine a to m an in t r am olecu la r hy dro genb o n d i s f o r m e d b e t w e e n t h e N - H p r o t o n a n d t h e a - c h l o r o a t o m a s d e pi c t e d he r e:

o

o r

CI . . . H Cl 9 9 ' H


7/54

Variables in D ata Interpretation 219The fo rmat ion o f the C1- - -HN bond caus es v N - H to dec reas e in f r equency whi le the vC=Omo de i s on ly inc reas ed by 4 to 5 cm -1 . W i th the ad d i t ion o f the s econd and th i rd ch lo r ine a tom sthe v N - H f r equenc ies inc rease p rogres s ive ly by 6 to 14 cm -1 and 6 to 9 cm -1 wh i le the vC =Ofrequenc ies inc rease p rogres s ive ly by 18 to 2 2c m -1 an d 21 to 2 3c m -1 . The v N - H f r e q u e n c yincreas es w i th the add i t ion o f the s econd and th i rd a - ch lo r ine a toms and i s the r es u l t o f theinduc t ive e f fect . I n the cas e o f the vC =O f r equenc ies s ubs t i tu t ion o f the s econ d and th i rdch lo r ine a tom s i s a comb ina t ion o f the induc t ive e f fec t and the f i eld ef fec t be twe en the ca rbo ny loxygen a tom and the two gauche ch lo r ine a tom s (6 ).

C o m p a r i s o n o f t he v a p o r a n d C C 1 4 s o l u t i o n d a t a f o r N - i s o p r o p y l a c e ta m i d e ( 3 4 6 0 v s34 51 cm -1 and 1714 vs 168 7cm -1 ) and N- te r t -bu ty l a ,0~ ,0~ -t ri chlo roace tamide (3444 vs3 4 3 5 c m - 1 a n d 1 7 43 v s 1 72 5 c m - 1 ) s h o w s t h a t b o t h v N - H a n d v C = O o c c u r a t h ig h e r f r e q u e n c yin the vapor. Th i s mo s t l ikely r e fl ec ts the e f f ec t o f N-H . . . C1 CC 13 in te r ac t ion in the s o lu t ionphase.

T h e v N - H v i b r a t i o n o c c u r s a t t h e l o w e s t f r e q u e n c y f o r t h e N - p h e n y l a n a l o g s o f t h efo rem en t ione d fou r s e ri e s o f ace tamides . The N -phen y l ana logs o f thes e s e ri e s exh ib i t vN - Ha t t h e l o w e s t f r e q u e n c y i n t h e o r de r : C H 3 ( 3 4 4 9 c m - 1 ) , C 1C H 2 ( 3 4 0 9 c m - 1 ) , C 1 2 C H( 3 4 1 9 c m - 1 ) , a n d C 1 3C ( 3 4 25 c m - 1 ) , a n d e x h i b i t v C = O a t t he h i g h e s t f r e q u e n c y in t h e o r d e r:C H 3 ( 1 7 0 8 c m - 1 ) , C 1 C H2 ( 1 6 9 2 c m - 1 ) , C 1 2 C H ( 1 7 1 3 c m - 1 ) , a n d C C 1 3 ( 1 7 3 1 c m - 1 ) . T h einduc t ive e f f ec t o f the pheny l g roup t igh tens the C=O bond , the reby r a i s ing i t s vC=O f r equency ,a n d t h e N - H g r o u p b e c o m e s m o r e a c i d i c , c a u s i n g i t t o f o r m a s t r o n g e r i n t r a m o l e c u l a rN - H . . . C 1 b o n d . T h e v N - H a n d v C = O f r e q u e n c y b e h a v i o r w i t h ~ z -c h lo r o s u b s t i t u t i o n iscomparable to that exhibi ted by the N-alkyl 0~-chlor inated analogs .

N - H I N T E N S I T YA s tudy o f Table 12 . 2 s hows tha t the app aren t in t r in s ic in teg ra ted abs o rp t ion (B x 108) * fo r theN - H s t r e tc h i n g v i b r a ti o n is s i gn i fi c a nt l y r a is e d b y t h e in t r a m o l e c u l a r N - H - . - X b o n d , w h i l e t h eintens i ty is inf luenced only to a re la t ively small extent by the induct ive ef fect .

I n sa t u r a t io n s o f 1 0% o r < 10 % , CC 1 4 s o l u t io n s b o n d e d v N - H . . - O - - C o c c u r i n t h e r e g io n32 80 -34 00 cm -1 ( s ee Tab le 12 . 2a) . F o r thos e com po und s tha t exh ib i t ed s ign i f i can t " amide II "over tone abs o rp t ion , bo th the obs e rved f r equenc ies and f r equenc ies co r r ec ted fo r F e rmires onance w i th the "amide l I " over tone a r e l i s t ed .

T h e f r e q u e n c y s e p a r a t i o n b e t w e e n t h e v N - H f r e q u e n c y a n d t h e i n t e r m o l e c u l a rv N - H - - - O = C f re q u e nc y va ri es b e tw e e n 6 0 a n d 1 9 5 c m - 1 T h e i n tr a m o l e cu l a rl y h y d r o g e n -b o n d e d s e c o n d a r y a m i d e s e x h i b i t l e s s i n t e r m o l e c u l a r H - b o n d i n g t h a n t h e s i m p l e N - a l k y la c e t a m i d e s , a n d e x h i b i t h i g h e r b o n d e d v N - H f r e q u e n c i e s .

In con t r as t , py r ro l idone i s a cyc li c s econd ary amide whos e N - H g roup i s c is w i th the C- -Ogroup . In th i s cas e, the vN -H f r equency i s nea r ly indepe nde n t o f conce n t r a t ion , r ang ing f rom

* B x 108 [Intensity B-- (1 /CI) In (Io/I)dv in CM2 molecule 1 S 1 , and represents the apparen t intrinsic absorptionfor v N - H ] .


8/54

220 Carboxam ides , U reas , Thioureas , Imidazol id inones , Caf fe ine , I socaf fe ine , Urac il s , Imides , e t c .3 2 0 7 - 3 2 1 9 c m - 1 a t c o n c e n tr a t io n s r a n g in g f r o m 0 . 0 1 - 1 . 0 M i n C C 1 4 so lu t io n . T h i s i n d ica t e sth a t o n ly o n e b o n d ed sp ec i e s i s p r e sen t : t h e c i s d im er ( 1 0 ) .

p y r r o l i d o n e c i s i n t e r m o l e c u l a r h y d r o g e n b o n d e d d i m e rT ab le 1 2 .3 l i st s IR d a ta f o r N- a lk y l a - su b s t i t u t ed ace t am id es in 1 0 % wt . /v o l , an d 0 .0 0 2 M CC14

so lu t io n s . I n a l l c a se s , ex cep t f o r t e r t - b u ty l p h en o x y - ace t am id e an d t e r t - b u ty l t r i ch lo r o ace t a -m id e , t h e v C= O o r " Am id e I " m o d e o ccu r s a t h ig h e r f r eq u en cy in d i lu t e so lu t io n . W i th in eachse r i e s , t h e t e r t - b u ty l an a lo g s sh o w th e l e a s t f r eq u en cy sh i f t i n g o in g f r o m 1 0 % wt . /v o l , t o0 .0 0 2 M in C C 1 4 so lu t io n ; an d th i s i s m o s t l i k e ly d u e to t h e s t e r i c e f f ec t o f t h e t e r t - b u ty l g r o u p ,w h i c h p r e v e n t s t h e N - H p r o t o n o f a n o t h e r a m i d e m o l e c u l e f r o m fo r m i n g a s s t r o n g anin t e r m o lecu la r h y d r o g en b o n d a s i n t h e ca se o f t h e o th e r N- a lk y l an a lo g s , o r p r ev en t sin t e r m o lecu la r h y d r o g en b o n d in g a s i n t h e ca se o f t e r t - b u ty l t r i ch lo r o ace t am id e .

T ab le 1 2 .4 sh o ws a co m p a r i so n o f p r im ar y an d sec o n d a r y am id es in t h e so l id p h ase . I n t h isca se, t h e v a sy m . N H 2 fr eq u en c ie s o ccu r i n t h e r an g e 3 3 1 0 - 3 3 8 0 c m - 1 an d v sy m . N H 2f r eq u e n c ie s o c c u r i n t h e r a n g e 3 1 5 0 - 3 1 9 5 c m - 1 w h i l e v N - H f o r t h e seco n d a r y am id es o ccu ri n t h e r a n g e 3 2 4 2 - 3 3 4 0 c m - 1 . T h e p r i m a r y a m i d e s e x h i b i t N H z b e n d i n g i n t h e r e g io n 1 6 2 0 -1 6 5 2 c m - 1 w h i l e th e s e c o n d a r y a m i d e s e x h ib i t N - H b e n d i n g i n t h e r e gi o n 1 5 2 5 - 1 5 5 0 c m - 1 .I n d u c t iv e an d r e so n an ce e f f ec t s u p o n th e v C= O f r eq u en cy a r e a l so ap p a r en t i n t h e so l id p h ase .

Table 12 .4a l i s t s IR da ta fo r the vC=O f requencies fo r te r t ia ry amides in the nea t o r so l idp h ase . Fo r m am id es h av e th e b a s i c s t r u c tu r e :

oII/ ~ 2 1 5H N~Y

I n t h e n ea t p h ase , w h en X an d Y ar e C zH 5 g r o u p s , v C = O o ccu r s a t 1 6 6 5 cm - 1 . W h e n X i s C 2 H 5an d Y i s C6 H 5 , v C = O o ccu r s a t 1 6 7 0 cm - 1 . W h e n X is C6 H s an d Y i s C6 H 5 , v C = O o ccu r s a t1 6 9 0 cm - 1 . T h e in c r ea se in t h e v C = O f r eq u en cy w h en C6 H 5 i s su b s t i t u t ed f o r C2 H 5 i s a t t r i b u tedto the la rger induct ive e f fec t o f C 6 H 5 v s C 2 H 5. T er t i ar y am id es h av e th e f o l lo win g b as i c s t r u c tu r e :

oi l/o\/xR N'

T h e t e r t i a r y ace t am id es ex h ib i t v C- - O in th e r eg io n 1 6 5 0 - 1 6 7 0 c m - 1 , an d th e in d u c t iv e e f fec t o fth e X o r Y a lk y l an d p h en y l g r o u p s i s a lso ap p a r en t . I n t h e v ap o r p h ase , v C = O f o r t e r t i a r y am id eso ccu r 4 0 4 - 5 c m - 1 h ig h e r i n f r eq u en cy th an th ey o ccu r i n t h e n ea t o r so l id p h ase . T h e lo wer


9/54

V a r i a b l e s i n D a t a I n t e r p r e t a t i o n 221v C = O f r eq u en c ie s in t h e co n d en sed p h ase s m o s t l ik e ly r e su l t fr o m d ip o la r i n t e r ac t io n b e twee nm o lecu le s su ch a s t h e o n e i l l u s t r a t ed h e r e ; t h i s i n t e r ac t io n weak en s th e C= O b o n d .

O - /~ R ,) 2 N ~ , R/(R ') - O

T ab le 1 2 .5 sh o ws a co m p ar i so n o f Ram an d a t a an d a ss ig n m en t s f o r a c r y lam id e , m e th ac r y -l am id e , an d th e i r p o ly m er s . S tu d y o f T ab le 1 2 .5 in d ica t e s t h a t a s t h e av e r ag e m o lecu la r w e ig h t o fp o ly ac r y l am id e in c r ea ses , t h e v C = O f r eq u en cy in c r ea se s f ro m 1 6 5 8 to 1 6 6 8 cm - 1 , wh i l e t h eRam an r e l a t iv e b an d in t en s i ty d ec r ea se s . T h e N- a lk y l a c r y l am id es ex h ib i t a weak Ram an b an d inth e r eg io n 1 6 5 7 - 1 6 5 9 c m - 1 a n d a s t ro n g R a m a n b a n d i n t h e re g i o n 1 6 2 7 - 1 6 2 9 c m - 1 , w h i c h a r ea ss ig n ed to v C- - O an d v C- C, r e sp ec t iv e ly . T h e N ,N- d ia lk y l o r N- a lk y l , N- v in y l a c r y l am id esex h ib i t a wea k to s tr o n g Ram an b an d in t h e r eg io n 1 6 4 8 - 1 6 6 6 cm - 1 an d a s t r o n g Ram an b an d inth e r eg io n 1 6 0 9 - 1 6 2 5 c m - 1 , wh ich a r e a s s ig n ed to v C= O an d v C= C, r e sp ec t iv e ly . T h e in d u c t iv ee f f ec t o f t h e N- v in y l g r o u p ap p a r en t ly a f f ec t s b o th th e f r eq u en cy an d Ram an b an d in t en s i ty o fv C = O .

M e t h a c r y l a m i d e e x h ib i ts a w e a k R a m a n b a n d a t 1 6 7 3 c m - 1 , w h i c h i s 9 c m - 1 l o w e r i nf r eq u en cy th an v C= O f o r a c r y l am id e . T h i s d ec r ea se in t h e v C- O f r eq u en cy i s a t t r i b u ted toth e in d u c t iv e e f f ec t o f t h e a - m e th y l g r o u p . T h e m ed iu m - s t r o n g Ram an b a n d a t 1 6 4 7 cm - 1 i sa s s ig n e d as v C - C f or m e t h a c r y l a m i d e w h i l e t h e s tr o n g R a m a n b a n d a t 1 6 39 c m - 1 i s ass igned asv C= C f o r a c r y l am id e . Ap p a r en t ly t h e in d u c t iv e e f f ec t o f t h e a - m e th y l g r o u p in p o ly m e th ac r y -l am id e cau se s v C= O to o ccu r a t l o wer f r eq u en cy th an v C= O f o r p o ly ac r y l am id e .

T ab le 1 2 .5 a l i s t s Ram an d a t a f o r N- a lk y l o r N- a r y l a c r y l am id es an d m e th ac r y l am id es in t h en ea t p h ase . T h e m o s t d i s t i n g u i sh in g f ea tu r e s b e tween th e N- a lk y l o r N- a r y l a c r y l am id es an d th eN- a lk y l o r N- a r y l m e th ac r y l am id es i s t h e r e la t i v e Ram an b an d in t en s i t i e s o f vC=O/vC=C. In thecase of t h e ac r y l am id es i t v a ri e s b e tween 0 .0 6 an d 0 .8 an d in t h e ca se o f t h e m e th ac r y l am id es i tv a r i e s b e tween 0 .1 1 an d 3 . Mo r eo v e r , t h e f r eq u en cy sep a r a t io n b e tween v C- - O an d v C= C v a r i e sb e t w e e n 2 9 - 3 5 c m - 1 f o r th e a c r y l a m i de s a n d v a ri e s b e tw e e n 3 5 - 3 9 c m - 1 f or t h e m e t h a c r y l a -m id es .

A s t r o n g Ram an b an d in t h e r an g e 8 7 5 - 8 8 1 c m - 1 m o s t l i k e ly r e su l t s f r o m a sy m m et r i cC - C - C s k e le t al s tr e t c h in g v i b ra t i o n o f t h e g r o u p f o r t h e m e t h a c r y l a m i d e w h i le a m e d i u m -s t r o n g Ram an b an d in t h e r an g e 1 2 3 6 - 1 2 5 6 cm - 1 r e su l t s f r o m a sk e l e t a l v ib r a t io n o f t h e- - - - C- C( - - ) - N g r o u p f o r t h e ac r y l am id es .

\ ?C - ' - ' ~/ \ C aTable 12 .6 l is t s IR da ta fo r p -x-ace ta n i l ides and p-x , a -h a loace tan i l ides . Study o f Tab le 12 .6

sh o ws th a t i n g en e r a l a ll v C = O m o d es o ccu r a t lo wer f r eq u en cy in CHC1 3 so lu t io n th an in CC1 4so lu t io n . Pa r t o f t h e v C= O f r eq u en cy d ec r ea se is t h e r e su l t o f i n t e r m o lecu la r h y d r o g e n b o n d in g( C= O . - - HC C1 3 ) . I t sh o u ld b e n o ted th a t th e v C= O f r eq u en c ie s i n c r ea se in th e o r d e r a - b r o m o - p -x - ace t an i l i d e, p - x - ace tan i l i d e , an d a , a , a - t r i ch lo r o - p - x - ace t an i li d e . T h e a - b r o m o an a lo g s an d th e


10/54

222 C a r b o x a m i d e s , U r e a s , T h i o u r e a s , I m i d a z o l i d i n o n e s , C a f f e i n e , I s o c a ff e i n e , U ra c i l s , I m i d e s , et c .a , a , a - t r i ch lo ro ana logs in d i lu te s o lu t ion ex i s t in the in t r am olecu la r hyd roge n bon ded fo rm asdep ic ted he re :

14 . . . XAs d i s cus s ed p rev ious ly , s ubs t i tu t ion o f the f i r s t a -ha logen a tom on the a - ca rbon a tom decreas esthe vC- -O f r equency . Add i t ion o f the s econd and th i rd ha logen a toms on the a - ca rbon a tomadd i t ive ly inc reas es the vC- -O f r equency due to bo th induc t ive and f i e ld e f f ec t s (7 ) .

F igu re 12 .3 s hows p lo t s o f the vC =O f r equenc ies o f a -b romo -p-x -ace tan i l ide , p -x -ace tan i l ide ,and a , a , a - t r i ch lo ro -p -x -ace tan i l ide in 0 . 00 2M s o lu t ions o r l e ss in C C I 4 and CHC13 vs theHa mm et t ap va lues . A ll s ix p lo t s s how tha t the vC =O mo de inc reas es l inea r ly in f r equenc y as theap va lue inc reas es . Th i s i s the r es u l t o f the g rea te r t endency o f the pa ra s ubs t i tuen t to a t t r ac te lec t rons (h igher ap va lues ) , the s mal le r the n i t rogen nonbond ing e lec t ron pa i r . The ca rbony ls t r e tch ing f r equency dec reas es as the e lec t ron dens i ty on the n i t rogen a tom inc reas es as a r e s u l to f an inc reas ed t endenc y towa rd s h i f ting the mes om er ic equ i l ib r ium:

~fl /O ,, ~ /H H:~C/C,~N* l

F or example , the h igher the n i t rog en e lec t ron dens i ty , the g rea te r the t endenc y to impar t doub le -b o n d c h a r a c te r t o t h e C - N b o n d a t t he e x p e n s e o f d o u b l e - b o n d c h a r a c te r o f t h e C - -- O b o n d ,thus r educ ing the C=O fo rce cons tan t (7 ) .

A C E T A N I L I D E SI t has been s hown tha t the IR vC=O band in tens i t i e s fo r p - and m-s ubs t i tu ted ace tan i l ides a r e afunc t ion o f Ha mm et t ap and am va lues (11 ) . The h igh er the ap o r a m va lues the lower the vC =OIR band in tens it i e s . Exam ples g iven he re a r e f rom Refe rence (7 )"

p - x p - x - a c e t a n i l i d e ~ - b r o m o - p - x - a c e t a n i l i d e ~ , ~ , ~ - t r i c h l o r o - p - x - a c e t a n i l i d eC H 3 0 1 4 . 4 1 5 . 1 0 1 3 . 4 2C 1 1 2 . 5 6 1 4 . 4 1 1 2 . 9 3N O 2 9 . 4 0 1 1 . 1 5 1 1 . 5 5T h e s e a b s o r b a n c e v a l u e s a r e 1 0 7 c m 2 m o l e c u l e - 1 S -1

Tab le 12 . 7 li s ts IR da ta fo r the N - H s t r e tch ing f r equenc ies fo r p -x -ace tan i l ides and p -x , a -ha loace tan i l ides an d the i r abs o rb ance va lues ( 7 cm 2 molec u le -1 s - I ) ob ta ined in CHC13s o lu t ion . The aN - H f r equenc ies genera l ly occur a t lower f r equency in CHC13 s o lu t ion tha n in


11/54

Variables in Data Interpretation 223CC14 so lu t io n . T h e v N - H f requencies in CC14 so lu t io n d ec r ea se in t h e o r d e r p - x - ace t an i l i d e( 3 4 3 6 - 3 4 4 5 c m - 1 ) , 0 ~ ,0 ~ ,~ - tr ich lo ro -p -x -acet an il id e ( 3 4 1 5 - 3 4 2 2 cm - 1 ) , an d 0 ~- br o m o -p - x- ace t a-n i l id e ( 3 3 9 1 - 3 4 0 5 ) . I n CHC1 3 so lu t io n th ey o ccu r i n th e sam e o r d e r, 3 4 2 9 - 3 4 4 0 cm - 1 , 3 4 0 6 -3415 c m - 1 , a n d 3 3 8 7 - 3 3 9 5 c m - 1 .

Stu d y o f t h e ab so r b an ce v a lu e s sh o ws th a t i n g en e r a l t h ey in c r ea se p r o g r e ss in g in t h e o r d e rp-x-ace tan i l ide , 0~-bromo-p-x-ace tan i l ide , and 0~,~,~-p-x-ace tan i l ide . There i s a genera l bu t no tsystem at ic increase in the absorba nce va lues as the crp va lues increase . T hese da ta sup po r t tha t ani n t r am o l e c u l a r h y d r o g e n b o n d i s f o r m e d b e t w e e n N - H - - - X a s al r ea d y d e p i c te d h e r e . I n th e c a seof the 0~-Br ana log , the Br a tom is la rger than say a C1 a tom , an d the H .- -B r d is tance wo uld besh o r t e r t h an th e H . . .C1 d i s t an ce . A s t r o n g e r i n t r am o lecu la r h y d r o g en b o n d wo u ld b e f o r m ed a sthe d is tance i s decreased , causing v N - H . . . B r t o d ec r ea se in f r eq u en cy b y ap p r o x im a te ly40 c m - 1 . T h ese d a t a sh o w th a t a s t h e N- H p r o to n b eco m es m o r e ac id i c , t h e v N - H f r eq u en cydecreases (7 ) .

N - A L K Y L B E N Z A M I D E ST ab le 1 2 .8 li s ts t h e NH an d C = O s t r e t ch in g f r eq u en c ie s fo r N- a lk y l p - m e th o x y b en zam id e , N-a lk y l p - ch lo r o b en zam id e , an d N- a lk y l m e th y l c a r b am a te in CC14 so lu t io n s ( 6 ) . T h e ab so r b an cevalues a re x 108 cm 2 mo lecu le -1 S-1 f o r t h e NH g r o u p .

T h e N- a lk y l p - x - b en zam id es a r e a l so a f f ec t ed b y th e n a tu r e o f t h e N- a lk y l g r o u p . T h e v N - Hf requencies genera l ly decrease wi th b ranch ing on the N-a lky l 0~-carbon a tom.

T h e v C= O f r eq u en c ie s f or t h e N- a lk y l p - m e th o x y b en z am id es o ccu r i n t h e r an g e 1 6 7 0 -1 6 7 6 cm - 1 an d f o r N- a lk y l p - ch lo r o b en z am id e s in t he r an g e 1 6 7 1 - 1 6 8 1 c m - 1 . Clo se r ex am in a -t io n sh o ws th a t i n a l l c a se s v C= O f o r n - a lk y l p - m e th o x y b en zam id e o ccu r s a t a l o wer f r eq u en cyth an th a t f o r t h e co m p ar ab le N - a lk y l p - ch lo r o - b en za m id e ( N- m e th y l v s N- m e th y l , e t c . ). T h i s isthe resu l t o f Ham m et t Crp va lues . T he Crp va lues a lso appea r to a f fec t the b and in tensi t ies , becaus ea h igher ~rp va lue increases the ba nd in tensi ty .

N - A L K Y L M E T H Y L C A R B A N A T E ST h e N - a l k yl m e t h y l c a r ba n a t es e x h i b i t v N - H i n t h e re g i on 3 4 4 9 - 3 4 7 8 c m - 1 ; a n d t h e f re q u e n -c ie s t en d to d ec r ea se wi th b r an ch in g o n th e 0 ~-ca rb o n a to m . T h e N - p h en y l an a lo g ex h ib i t s v N Ha t 3 4 5 0 c m - 1 . T h e v C = O f r eq u en c ie s f o r t h e N- a lk y l an a lo g s o ccu r i n t h e r an g e 1 7 3 0 -1 7 3 8 cm - 1 wh i l e v C = O f o r t h e N- p h e n y l an a lo g o ccu r s a t 1 7 4 8 cm - 1 d u e to t h e in d u c t iv eef fec t o f the phenyl r ing (6 ) .

N , N ' - D I A L K Y L O X A M I D E S A N D N , N ' - D I A R Y L O X A M I D ET ab le 1 2 .9 li s ts I R an d R am an d a t a f o r b o th N ,N ' - d i a lk y l o x am id es a n d N ,N ' - d i a r y l o x am id es(12) . In the case o f IR, the samp les we re p repa red as e i ther sp l i t mu l ls o r KBr pe lle ts . Ram ansp ec t r a we r e r eco r d ed o f t h e so lid sam p le s . T h e o u t - o f - p h ase ( N - H ) 2 s t r e t ch in g v ib r a t io n ( a Bi ,m o d e ) i s I R ac t iv e an d in t h e ca se o f t h e N ,N ' - d i a lk y l an a lo g s o ccu r s i n t h e r an g e 3 2 7 9 -


12/54

2 2 4 Carboxamides, Ureas, Thioureas, Imidazol idinones, Caffeine, Isocaffeine, Uraci ls , Imides, etc .3311 c m - 1 whi le fo r the N , N ' -d ia ry l ana logs i t occu r s in the r ange 3 29 5- 33 58 cm -1 . The in -phas e (N -H ) 2 s t r e tch ing v ib ra t ion ( an Ag mo de) i s Ram an ac t ive and in the cas e o f the N , N ' -d ia lky l ana logs it occu r s in the r ange 33 02- 332 5 c m - 1 whi le fo r the N , N ' -d ia ry l ana logs i t occu r si n t h e r a n g e 3 3 2 0 - 3 3 4 9 c m - 1 . T h e I R b a n d o c c u r r i n g i n t h e r a n ge 1 6 4 3 - 1 6 6 0 c m - 1 f o r N ,N ' -d ia lky l oxamides i s a s s igned to the am ide I mode ( in th i s cas e , ou t -o f -phas e (C =O ) 2 s t r e tch ing )whi le fo r the N , N ' -d ia ry l ana log it occu r s in the r ange 166 2-17 19 c m - 1 . In the sol id s ta te , a weaks hou lder appear s in the r eg ion 16 28 -16 38 cm -1 o f the IR s pec t rum . I t i s the r es u l t o f c rys ta ls p l i t ting , a s i t i s no t p res e n t in s o lu t ion phas e o r vapor -phas e s pec t r a (12 ) . The in -phas e (C =O ) 2s t r e tch ing Ag mo de i s a s s igned to the Ram an band occur r ing in the r ange 1 686 -169 5 c m - 1 in thecas e o f the N , N ' -d ia lky l ana logs wh i le in the cas e o f the N , N ' -d ia ry l ana logs i t occu r s in the r ange1 6 8 2 - 1 7 4 1 c m - 1 .

T h e A m i d e II m o d e m t h e o u t- o f- p h as e ( N - H ) 2 b e n d i n g ( B l u ) m o d e a n d t h e i n- p h as e ( N - H ) 2b e n d i n g ( A l g ) m o d e m o c c u r i n t h e r a n g e 1 5 0 8 - 1 5 4 1 c m - 1 a n d 1 5 4 7 - 1 5 6 7 c m - 1 f o r t h e N , N ' -d ia lky l oxamides , r e s pec t ive ly , wh i le fo r the N , N ' -d ia ry l ana logs they occur in the r ange 1484-1520 c m - 1 and 153 7-155 0 cm -1 , r e s pec t ive ly. In a l l cas es d i s cus s ed he re the Ag mo des occur a th i g h e r f r e q u e n c y t h a n t h e c o r r e s p o n d i n g B lu mode . Thes e IR and R aman da ta ind ica te tha t theN , N ' -d ia ry l oxamide ex i s t in an in te rmolecu la r ly hydrogen-bonded t r ans conf igu ra t ion in thes o l id s t a te where each oxamide g roup can be v iewed as hav ing C2h s ymmet ry (12 ) . In the vaporphas e N , N ' -d imethy loxamide a l s o ex i s t s in the t r ans conf igu ra t ion (12 ) .

The N , N ' -d ia lky loxamide exh ib i t s B lu mo des in the r ange 12 23-125 1 cm -1 (Am ide I II ) , 72 5-78 2c m -1 (Amide IV) , 532-6 19 cm -1 (Amide VI ) , and Ag mo des in the r eg ion 1298 -1315 cm -1( A m i d e I II ), a n d 1 1 3 0 - 1 2 1 0 c m - 1 ( ( C - N ) 2 s t r e tc h i n g ) ( 1 2 ).

D I M E T H Y L A C E T A M I D E A N D T E T R A A L K Y L U R E ATable 12 . 10 li s ts IR da ta and as s ignm en ts fo r d ime thy lace tam ide and t e t r aa lky lu rea in d i f f e ren tphys ica l phas es (13 ,14 ) . Thes e da ta s how tha t the C = O s t r e tch ing f r equency o f d imethy lace -tamide o r t e t r aa lky lu rea i s s ens i tive to the phys ica l phas e , and tha t in n-C6H14/CHC13s o l u t i o n sc lus te r s o f t e t r ame thy lu rea ex i st tha t exh ib i t vC =O a t 1650 . 9 and 163 5 . 4cm -1 in 14 mo l % n -C6H14/CHC13and a t 1640 . 2 and 1629 . 5 c m - 1 in 80 . 6 mol % n-C6H14/CHC13s o lu t ions .

In C C 14 a n d / o r C H C 1 3 s o l u ti o n s , t h e b e h a v i o r o f t h e C = O s t r e tc h i n g m o d e i s e x p l a i n ed o nt h e b a si s o f h y d r o g e n - b o n d e d c o m p l e x e s b e t w e e n s o l v e n t- s o lv e n t a n d s o l u t e - s o l v e n t a n d t h ebu lk d ie lec t r i c e f f ec t s o f the s o lven t s . F igu re 12 . 4 s hows p lo t s o f vC- -O fo r i w t % s o lu t ions o face tone , d imethy lace tamide , and t e t r amethy lu rea vs mole % CHC13/CC14 . The p lo t s becomemore complex p roceed ing in the s e r i e s ace tone , d imethy lace tamide , and t e t r amethy lu rea . In thecas e o f ace tone , the non l ine a r s egm en t i s a t t r ibu ted to the complex (CH3) 2 C= O. . . H CC 13 , andt h e f i r s t n o n l i n e a r s e g m e n t s i n t h e o t h e r t w o p l o t s a r e a t t r i b u t e d t o C - O . . . H C C 1 3 c o m p l e x e swi th d im ethy lace tam ide and t e t r aa lky lu rea . The s econd b reak in the case o f d ime thy lace ta midei s a t t r i b u t e d t o i n t e r m o l e c u l a r h y d r o g e n b o n d i n g b e t w e e n b o t h C 1 3 C H . . . O - - C - N ( . - - H C C 1 3 .T h e t h i r d b re a k m a y b e d u e to a c o m p l e x s u c h a s ( C 1 3 C H . - . ) 2 0 - - C - - N . . .H C C 1 3 a n d / o rC 1 3 C H . . . O = C - N ( . . - H C C 1 3 ) 2. T h e a d d i t io n a l b r e a k i n N , N , N ' , N ' -t e t r a m e t h y l u r e a i s a t t r i b u t e dto the add i t iona l - N -g ro up , wh ich a l s o i s capab le o f fo rming a C13CH . . .N bo nd .

I t i s in te r es t ing to com pare the vC =O f r equenc ies o f t e t r am ethy lu rea (TMU ) , t e t rae thy lu rea(TEU) , and t e t r abu ty l u rea (TBU) in C C 14 s o lu t ion (1652 . 9 , 1646 .2 , and 164 3 . 2c m -1 ,


13/54

Variables in Data Interpretation 2 2 5r e spec t iv e ly , an d in CHC 1 3 so lu t io n ( 1 6 2 7 .3, 1 6 2 0 .1 , an d 1 6 1 6 .1 cm - 1 , r e sp ec t iv e ly ) . T h ef r eq u en cy d i f f e r en ce b e tween th e se two so lv en t s i n c r ea se s i n t h e o r d e r 2 5 .6 , 2 6 .1 , an d27 .0 c m - 1 f o r T MU , T E U, an d T BU, r e sp ec tiv e ly . I n ad d i t io n , i t is n o ted th a t t h e C = O s t r e t ch in gf r eq u en cy d ec r ea se s i n t h e o r d e r T MU, T E U, an d T BU. T h ese d a t a sh o w th a t a s t h e a lk y l g r o u p sc o n t r i b u te m o r e o f a n i n d u c ti v e c o n t r i b u t i o n t o t h e C = O g r o u p t h e v C - - O m o d e d e c r e a s e s inf r e qu e n c y a n d t he s t r e n g t h o f t h e C - O . . . H C C 1 3 b o n d i n c r e a s e s ( 14 ) .Tab le 12 .11 l i s ts IR vapo r -phase da ta fo r u rea , th iou rea , an d gua n id i ne der iva t ives . Th ese da tas h o w t h a t t h e 1 , 1 ,3 , 3 -t e tr a a lk y l u re a s e x h i b i t a w e a k I R b a n d i n t h e r a n g e 3 3 3 8 - 3 3 5 8 c m - 1 ,wh ich r e su l t s f r o m th e f i r s t o v e r to n e o f C- - O s t r e t ch in g . As 2 v C- - O o ccu r s a t l o wer f r eq u en cyth an th e ca l cu la t ed 2 v C= O f r eq u en cy in each ca se , t h e 2 v C- - O m o d e ex h ib i t s p o s i t i v ean h a r m o n ic i ty .

T h e 1 ,1 ,3 ,3 - t e t r ae th y l th io u r ea ex h ib i t s a b an d a t ap p r o x im a te ly 1 0 8 5 c m - 1 tha t i s ass igned toC - S s t r et c h in g , v C = S . T h e 1 6 1 9 c m - 1 b a n d f or 1 , 1 , 3 , 3 - t e t r a m e t h y l q u a n i d in e i s a s s ig n e d t oC = N s t r e t ch in g , v C= N. Al l o f t h e co m p o u n d s l i s t ed in T able 1 2 .1 1 ex h ib i t a b an d in t h e r an g e1 2 3 9 - 1 3 3 4 c m - 1 , w h i c h m o s t l i k el y r e s u lt s f r o m a n a n t i s y m m e t r i c N C N s t r e t ch i n g m o d e .

1 , 1 ,3 , 3 - T E T R A M E T H Y L U R E A V S 1 , 3 - D I M E T H Y L - 2 -I M I D A Z O L I D I N O N ET ab le 1 2 .1 2 li s ts I R d a t a f o r 1 ,1 ,3 ,3 - t e t r am e th y lu r e a an d 1 ,3 - d im e th y l - 2 - im id azo l id in o n e inv a r io u s so lv en t s a t 1 % wt . /v o l . ( 1 4 - 1 6 ) . T h ese two co m p o u n d s h av e th e fo l lo win g em p i r i ca ls t r u c tu r e s :

0oH= , ~ H

L , l . , \ /T M U D M I

I n a l l so lv en t s , t h e v C = O m o d e f o r DMI o ccu r s a t h ig h e r f r eq u en c y th an v C= O f o r T MU. T h eo n ly ch em ica l d i f fe r en ce b e tween T MU an d DMI i s t h a t a ( CH2 ) 2 g r o u p h as b een s u b s t i t u t e d f o rtwo CH 3 g r o u p s , an d th e ch em ica l d i f fe r en ce i s m in im a l . T h e C = O g r o u p o ccu r s a t as ig n i f i c an t ly h ig h e r f r eq u en cy in t h e ca se o f DMI d u e to g eo m e t r i c r e s t r i c t i o n s o f t h e 5 -m em b er ed r in g , wh ich m ak es i t m o r e d i f f i cu l t f o r t h e ca r b o n y l c a r b o n a to m to m o v e in an d o u to f t h e r i n g d u r in g a cy c le o f v C = O . ( T h i s i s o f t en r e f e rr ed to a s r i n g s t ra in . I n an y v C - - O m o d e ,t h e b o n d a n g l e m u s t c h a n g e t o s o m e d e g r ee , a n d t h e s m a l le r t he X - C - Y a n g le t h e m o r e d i ff i cu l ti t i s f o r t h e C= O b o n d to v ib r a t e . )

o

I n T able 1 2 .1 2 u n d e r t h e so lv en t h ead in g , t h e n ea t p h ase i s l i s t ed as 1 , h ex an e 2 , seq u en t i a l l yto m e th y l a l co h o l a s 2 0 . T h ese n u m b er s a r e u sed to sh o w f o r wh ich so lv en t o r n ex t p h ase th ep a r t i cu l a r d a t a we r e r eco r d ed o r t h e d a t a d i f f e r en ce was d e t e r m in ed .


14/54

2 2 6 Carboxamides, Ureas, Thioureas, Imidazol idinones, Caffeine, Isocaffeine, Uraci ls , Imides, etc .F igure 12 .5 s hows p lo t s o f vC- -O o f DMI and T MU in the nea t p has e o r in I o f the 19 s o lven t s

v s v C = O ( h e x a n e ) m i n u s v C = O ( s o lv e n t ). T h e s e t w o p l o t s ar e li ne a r, a n d a n y s e t o f n u m b e r st r ea ted in the s ame mathemat ica l way w i l l y ie ld a l inea r r e la t ions h ip . The impor tan t po in t tono te in thes e two p lo t s i s tha t the number in each p lo t i s no t in the iden t i ca l s equence . Thes ed i f f e r ences s ugges t tha t the s o lu te - s o lven t in te r ac t ion i s no t comparab le in a l l cas es (16 ) . Th i ssugge s ts th at the s ter ic factor o f the (CH3) 2 or (CH3) 4 and (CH2) 2 g roups a l t e rs the s pa t ia ld i s t ance be tween s o lu te and s o lven t .

F igu re 12 .6 s hows p lo t s o f vC- -O fo r TMU a nd DM I vs the s o lven t accep to r num be r (AN) .T h e n u m b e r s 171 t h r o u g h 201 a r e fo r th e v C - O . - - H O R f r e qu e n c ie s f o r th e s e c o m p o u n d s i nte r t i a ry bu ty l a lcoho l , i s op ropy l a lcoho l , e thy l a lcoho l , and methy l a lcoho l , r e s pec t ive ly . Then u m b e r s 1 7 t h r o u g h 2 0 ar e fo r v C = O i n th e s e sa m e a l c o h ol s , b u t w h e r e t h e C = O g r o u p s a r e n o ti n t e r m o l e c u l a r l y h y d r o g e n b o n d e d . T h i s i n d i c a t e s t h a t i n t e r m o l e c u l a r l y b o n d e d a l k y l a l c o h o l s( R - O H ) c a n c l u s t e r i n s u r r o u n d i n g T M U o r D M I w i t h o u t f o r m i n g i n t e r m o l e c u l a r h y d r o g e nbonds w i th the s o lu te . P ro jec t ion o f thes e po in t s by das hed l ines on to the lower l ines ind ica testha t the AN va lues fo r the a lcoho ls a r e much lower than the va lues de te rmined by NMR (17) .Thes e p ro jec ted AN va lues fo r the a lcoho ls a r e comparab le to the AN va lues fo r a lky l e the r s .

F igu re 12 .7 s hows p lo t s o f vC- -O fo r DMI and TMU vs mole % CHC13/CC14. Bo th p lo t s s hows imi la r a, b , c, and d s egmen ts . I t has been s u gges ted tha t the conc en t r a t ion o f DMI o r TMUmolecu les a r e in equ i l ib r ium wi th the co ncen t r a t ion o f CHC13 an d / o r CC14 molecu les in r eg ions(a) through (d) . In addi t ion, as the mole % CHC13/CC14 is increased f rom 0 to 100, the (CHC13)one , two , th ree o r fou r complexes a r e r ep laced by (CC13H:C1C12CH) x complexes :

Reg ion ( a ) DMI o r TMU. . . (HCC13) 1Region (b ) DMI o r TMU. . . (HCC13) 2Region ( c ) DMI o r TM U. . - (HCC1 3) 3Reg ion (d ) DM I o r TM U-- . (HCC13) 4

C o m p l e x e s b e t w e e n CC14 and TMU or DMI wou ld a l s o dec reas e the vC=O f r equenc ies .D i f f e r en t complexes a r e r epor ted to be fo rmed be tween DMI o r TMU and mole % n -

C6H14/CCI 4 or m o l e % n-C6H14/CHC13 s o lu t ions (15 , 16 ) . Da ta in Tab le 12 . 13 s how tha t inmole % CHC13/CC14 s o lu t ions on ly one vC=O f r equency i s obs e rved , in mole % CC14/n-C6H14s o lu t ions two vC=O f r equenc ies a r e obs e rved , and in mole % CHC13/n-C6H14 s o lu t ions th reevC =O f r equenc ies a r e obs erved . Thes e a r e due to the p res ence o f d if f e r en t DMI c lus te rs in thes ev a r i o u s c o m p l e x s o l u t io n m i x t ur e s .

C A F F E I N E , I S O C A F F E I N E , 1 , 3 , 5 - T R I M E T H Y L U R A C I L ,1 , 3 , 6 - T R I M E T H Y L U R A C I L , A N D 1 , 3 - D I M E T H Y L - 2 , 4 -( 1 H , 3 H ) Q U I N A Z O L I N E D I O N ETab le 12 . 14 l i st s the in -phas e and ou t -o f -phas e (C =O ) 2 s t r e tch ing f r equenc ies fo r ca ff e ine ,i s oca f f e ine , 1 , 3 , 5 - t r ime thy lu rac i l , 1 , 3 , 6 - t r ime thy lu rac i l , and 1 , 3 -d imethy l -2 , 4 - (1H , 3H) qu inazo-


15/54

Variables in D ata Interpretation 227l i n ed io n e in CC1 4 an d CHC1 3 so lu t io n s ( 1 8 ) . A ll o f t h e se co m p o u n d s co n ta in th e d im e th y l cy c l i c6 - m em b er ed r in g a s sh o wn h e r e .

CH3I

H3 ~ y ~CH 3O

T h e t w o C = O s t r e tc h i n g m o d e s c o u p l e i n t o i n - p ha s e ( C = O ) 2, Yip (C=O)2, an d o u t - o f - p h ase( C = O ) 2 s t r e t ch in g , Vop ( C= O ) 2.The r ip (C =O ) mo de for caf fe ine occurs a t 1721 cm -1 in the vap or phas e , a t 1710 .6 cm -1 inCC14 so lu t io n , an d a t 1 7 0 8 .9 c m - 1 in CHC1 3 so lu t io n wh i l e t h e Vop ( C= O) 2 m o d e o ccu r s a t1 6 8 5 cm - 1 in t h e v ap o r p h ase , 1 6 6 7 .5 cm - 1 in CC1 4 so lu t io n , a n d a t 1 6 5 8 .4 cm - 1 in CHC1 3so lu t io n . W i th ch an g e in p h ase , t h e V o.. ( C= O) 2 m o d e sh i f t s m o r e in f r eq u en cy th an th e rip(C =O )2 m ode (17 .5 , 26 .6 , and 9 .1 cm -~) vs (10 .4 , 12 .1, and 1 .7 cm -1) .

In CC14 so lu t ion , caf fe ine , i socaf fe ine , 1 ,3 ,5 - t r imeth y l u rac i l , 1 ,3 ,6 - t r imeth y lurac i l , and 1 ,3-d im e th y l - 2 ,4 - ( 1 H,3 H ) - q u in azo l in ed io n e ex h ib i t Vip ( C= O) 2 in th e r an g e 1 7 0 6 .6 - 1 7 1 6 .3 cm - 1 ,an d in CHC1 3 so lu t io n in t h e r an g e 1 7 0 0 - 1 7 1 1 .3 cm - 1 .

T h e V op ( C = O ) 2 m o d e f o r 1 ,3 ,5 - t r im e th y lu r ac i l an d 1 ,3 - d im e th y l - 2 ,4 - ( 1 H ,3 H) - q u in azo l in e -d io n e i s i n Fe r m i r e so n an ce wi th a co m b in a t io n o r o v e r to n e , an d in t h e se two ca se s Vop ( C = O ) 2was co r rec ted fo r ER. Therefore , fo r these f ive com pou nd s Vop(C=O) 2 occurs in the rang e1 6 6 3 .4 - 1 6 6 9 cm - 1 in CC1 4 so lu t io n an d in t h e r an g e 1 6 5 2 .4 - 1 6 6 4 cm - 1 in CHC1 3 so lu t io n ( 1 8 ) .

Tab le 12 .15 l i s t s IR da ta fo r u rac i l s in the so l id phase . In the so l id phase , the u rac i ls no tsu b s t i t u t ed in t h e 1 ,3 - p o s it i o n ( co n ta in two N - H g r o u p s ) ex h ib i t Vip ( C - O ) 2 in t h e ran g e1 7 0 4 - 1 7 5 0 cm - 1 an d Vop ( C= O) 2 in th e r an g e 1 6 6 1 - 1 7 0 4 c m - 1 . T h e l i 3 ,5 - t r im e th y l an d 1 ,3,6 -t r ime thy l ana logs ex h ib i t bo th Vip (C =O )2 and Vop (C =O )2 a t lower f req uenc y in the so l id phas ethan in e i ther CC14 or CHC 13 so lu t ion . The f requen cy se para t io n b e tw een Vip (C = O ) 2 and Vop( C = O ) 2 v a r i es b e twee n 2 3 an d 8 0 c m - 1 in t h e so l id p h ase .

I M I D E STable 12 .16 l i st s IR vapo r -phase da ta and ass ignm ents fo r imide s (1 ) .

T h e im id es ex h ib i t an in - p h ase [ r ip ( C= O) 2 ] an d o u t - o f - p h ase [V op ( C= O) 2 ] s t r e t ch in gv ib r a tio n s . T h e r ip ( C = O ) 2 m o d e h as wea k e r ab so r b an c e th an th e ab so r b an ce f o r Vop ( C = O ) 2.On th i s b a s i s rip ( C - O ) , an d Vop ( C = O ) 2 f o r d i ace t am id e , [ CH 3 C( - - O) ]2 NH , a r e a s s ig n ed a t1738 and 1749 c m - 1 , respec t ive ly , in the vapor phase . Al l o f the o ther imides inc luded in Table1 2 .1 6 ex h ib i t rip ( C - O ) , a t h ig h e r f r eq u en cy th an Vop ( C = O ) 2. Fo r ex am p le , N- p h e n y ld ib en za -m i d e , C 6 H s ( C = O ) 2 N C 6 H 5, e x h i b i t r ip ( C - - O ) 2 an d Vop ( C - O ) 2 at 1 8 0 1 an d 1 7 0 2 cm - 1 ,respectively.


16/54

228 Carboxamides, Ureas, Thioureas, Imidazolidinones, Caffeine, Isocaffeine, Uracils, Imides, etc.S u c c i ni m i d e s, m a l e im i d e s , a n d p h t h a l i m i d e s c o n t a i n 5 - m e m b e r e d r in g s:

0 ~ 0 0 0H H

m H

0succinimide maleimide phthJmide

hydan to in a l s o con ta ins a s imi la r type imide s t ruc tu re :H/

HS ucc in imide exh ib i t s r i p ( C - - O ) 2 a n d Vo p (C- -O ) 2 a t 1820 and 1772 c m - 1 , respect ively , wh ile

i ts N- (2 , 6 -xy ly l ) ana log exh ib i t s rip (C =O ) 2 and Vop (C- -O) 2 a t 1790 and 17 41 cm -1 ,r espec tive ly . In th is case , the 2 , 6 -xy ly l g rou p can no t be cop lanar w i th the N ( - C = O ) 2 g rou pdue to the s t e r i c f ac to r o f the 2 , 6 -d imethy l g roups . The N-a lky lmale imides and N-a ry lmale i -m i d e s e x h i b i t r ip ( C = O ) 2 a n d Vop ( C = O ) 2 i n t h e r a n g e 1 7 8 0 - 1 8 2 0 c m - 1 a n d 1 7 3 0 - 1 7 4 5 c m - 1 ,respectively.

P h tha l im ide exh ib i t s rip (C= O) 2 and Vop (C =O ) 2 a t 1795 a nd 176 6cm -1 in the vapo r phas e ,r es pec t ive ly . S ubs t i tu t ion o f a 3 -o r -4 -n i t ro g roup r a i s es bo th v (C=O)2 modes , wh ich mos t l ike lyis the result of the ~rp and o"m e ff ec t. S ubs t i tu t ion o f a 3 -amino g rou p lower s bo th m ode ss ign i f i can t ly , and th i s mos t l ike ly i s the combined e f f ec t o f in t r amolecu la r hydrogen bond ingHNH...O=C an d the o m effect.

N-a lky lph tha l im ides ex h ib i t r ip (C =O ) 2 and Vop (C- -O ) 2 in the r ange 17 71 -1 78 9c m -1 an d17 34 -17 40 cm -1 , r e s pec tive ly , wh i le the N -a ry l ana logs e xh ib i t r ip (C -O ) 2 and Vop (C- -O ) 2 int h e r a n g e 1 7 9 5 - 1 8 0 0 c m - 1 a n d 1 7 3 5 - 1 7 4 6 c m - 1 , respectively.

Hy dan to ins in the v apor phas e exh ib i t r ip (C =O ) 2 and Vop (C =O ) 2 a t 1826 and 1785 c m - 1 ,r espec tive ly . The 5 , 5 -d im ethy lh ydan to in exh ib i t s r ip (C =O ) 2 a t 1811 c m - 1 and Vop (C = O ) 2 a t1775 c m - 1 in the vapor phas e ; however , in the s o l id phas e r ip (C=O )2 occur s a t 1779 c m - 1 , a n dVop (C =O ) 2 occur s a s a doub le t (1744 a nd 171 6cm -1) . Appa ren t ly in the s o l id phas e the Vop(C=O)2 mode i s s p l i t by c rys ta l l ine e f f ec t s .

The s - t ri az ine (1H,3H,5H)-triones have the bas ic s t ruc tu re :Io y N , , ~ o

I N \ ~ ~ " -and the s ubs t i tu en t g rou ps a r e jo ine d to the N a toms (hy drogen , a l ipha t i c o r a roma t ic g roups ) .F or the th ree co mp oun ds r eco rded in the vapor phas e , Vop (C =O ) 2 occur s in the r ange 171 0-172 0cm -1 . The r ip (C - -O) 2 mo de fo r the 1 , 3 -d ipheny l -5 -oc ty l ana log occur s a t 1 76 6cm -1 .


17/54

V a r i a b l e s i n D a t a I n t e r p r e t a t i o n 229A ll of t h e se i m i d e t y p e c o m p o u n d s e x h i b it a w e a k b a n d i n t h e r a n g e 3 4 7 0 - 3 5 7 0 c m - 1 , w h i c h

i s a s s igned to the com bina t ion tone rip (C =O ) 2 + Vop (C =O ) 2. In the v apor phas e , imides tha tc o n t a i n N - H e x h i b it a w e a k b a n d i n t h e r a n g e 3 4 1 5 - 3 4 5 5 c m - 1 as s igned to v N - H . In the caseo f h y d a n t o i n s , v N - H o c c u r s in t h e r a n g e 3 4 8 2 - 3 4 9 0 c m - 1 in the vapor phas e , and in the r ange3 2 0 5 - 3 2 1 5 c m - 1 i n t h e s o li d p h as e . O f c o u r se i n t h e s o l id p h a s e h y d a n t o i n s e x i st i n a ni n t e r m o l e c u l a r h y d r o g e n - b o n d e d s t a te .

4 - B R O M O B U T Y L P H T H A L I M I D E I N S O L U T I O NTab le 12 . 17 l i s t s IR da ta fo r 4 -b romobu ty lph tha l imide in C C 1 4 a n d / o r C H C 1 3 s o l u t io n s ( 1 9 ).These d ata sho w th at as the mole % CHC13/CC14 is increase d f ro m 0 to 100 bo th r ip (C=-O) 2 an dVop (C=O)2 decrease in f requency. In addi t ion, the Vop (C--O)2 mode decreases more than r ip( C = O ) 2 b y a f a c to r o f - - 3 . 5 .

H Y D A N T O I N STab le 12 . 18 l i st s IR da ta an d as s ign me n ts fo r hydan t o ins in the vapor a nd s o l id phas es . Thev N - H f r equenc ies occur in the r ange 3485-3495 c m - 1 in the vapor and in the r ange 3150-33 30 cm -1 in the s o l id phas e .

In the vapor phas e , rip (C - -O) 2 occur s in the r ange 1808 -182 5 cm -1 an d in the r ange 175 5-1783 c m - 1 in the s o l id phas e w h i le Vop (C =O ) 2 occur s in the r ange 1774-1785 c m - 1 in the vaporp h a s e a n d i n t h e r a n g e 1 7 0 2 - 1 7 4 4 c m - 1 in the sol id phase. In the four cases where the samehydan to in was s tud ied in bo th the vapor and s o l id phas es , the f r equency s epara t ion be tween Vip(C =O ) 2 and Vop (C= O)2 i s m uch l e ss in the vapo r phas e (34 -40 cm - I ) than i t is in the s o l idp h a s e ( 5 4 - 6 6 c m - 1 ) .

T R I A L L Y L - 1 , 3 , 5 - T R I A Z I N E - 2 , 4 , 6 - ( 1 H , 3 H , 5 H ) T R I O N ETable 12.19 l is ts IR data and ass ignments for t r i a l l y l - l , 3 , 5 - t r i a z i n e - 2 ,4 ,6 - ( 1 H ,3 H ,5 H) t r ione inCHC13 an d /o r CC14 s o lu t ions (20 ) . The empi r i ca l s t ruc tu re o f th i s com po un d i s

OR ~ N , ~ N ~ RIR

where R i s a l ly l , and fo r s impl ic i ty we w i l l name th i s compound T30ne . T30ne has beend e t e r m i n e d t o h a v e D 3 h s ymm et ry , the r ip ( C =O ) 3 mo de be longs to the g ' s pec ies , and the r ip(C =O ) 3 m ode be longs to the A ' s pec ies. Th e Vop (C= O)3 m ode i s dou b ly degenera te , a nd i s IRac t ive wh i le r ip (C =O ) 3 i s Raman ac t ive . T3one in 1% wt . /vo l . CC14 s o lu t ion exh ib i t s a s t rongRam an ban d a t 1 761 . 2cm -1 , a t 5% wt . /vo l . CC14 s o lu t ion a t 1762 . 3 cm -1 , and a t 10% wt . /vo l .


18/54

230 Carboxam ides , U reas , Thioureas , Im idazol id inones , Caf fe ine , I socaf feine , Urac il s , Imides , e t c .C C 1 4 so lu t io n a t 1 7 6 3 .0 c m - 1 . I n CHC1 3 so lu t io n s a t t h e sam e % wt . /v o l , co n ce n t r a t io n s , s t r o n gRam an b an d s o ccu r a t 1 7 5 8 .3 , 1 7 6 0 .5 , an d 1 7 6 1 .4 c m - 1 , r e spec t iv e ly. T h e r e f o r e , i n b o th C C I 4an d CHC1 3 so lu t io n th e Ram an b an d in c r ea se s i n f req u en cy w i th an in c r ea se in t h e % wt . /v o l .T 3 on e . A co r r e sp o n d in g I R b an d i s n o t o b se r v ed , an d th i s Ram an b an d i s a s s ig n ed a s ri p ( C= O ) 3 .

In the case o f Vop (C = O ) 3 fo r T3one , 1 and 5% vol . / wt , so lu t io ns in C C14 sho w tha t i td ec r ea se s i n f r eq u en cy f r o m 1 6 9 8 .6 c m - 1 to 1 6 9 8 .5 c m - 1 wh i l e a t t h e se sam e co n cen t r a t io n s inCHC13 i t decreases f rom 1695 .7 c m - 1 t o 1 6 9 5 . 5 c m - 1.

T h e Vop ( C = O ) 3 m o d e f o r T 3 o ne d ec r ea se s i n a n o n l in ea r m an n e r a s t h e m o le % CHC1 3 /CC14is increased f rom 0 to 100 as shown in Figure 12 .8 . These da ta ind ica te tha t d i f fe ren t T3one9 . ( HCC1 3 ) n co m p lex es a r e f o r m ed a s t h e m o le % CHC1 3 /CC1 4 i s i n c r ea sed , an d th a t i n g en e r a lth e V op ( C = O ) 3 f r eq u en cy d ec r ea se s w i th in c r ea se in t h e m o le % CHC1 3 /CC1 4 a r e d u e to t h ed ie l ec t r i c e f f ec t o f e ach p a r t i cu l a r so lv en t sy s t em .

A s t rong IR ban d ass ign ed to Vop (C3N 3) i s ass igned in the reg ion 145 5 .2-1 458 .6 c m - 1 . T h i sm o d e in c r ea se s i n f r eq u en cy in a lm o s t a l i n ea r m an n e r a s t h e m o le % CHC1 3 /CC1 4 i s i n c r ea sed(see Figure 12 .9) .

T h e a l ly l g r o u p s in T 3 o ne ex h ib i t t h r ee ch a r ac t e r is t i c f r eq u en c ie s . T h e v C = C m o d e i s n o ta f f ec t ed b y ch an g e in t h e so lv en t sy s t em , a s it o ccu r s a t 1 6 4 5 .4 cm - 1 . On th e o th e r h a n d , t h eC = C H 2 w a g m o d e d e c re a s e s i n f r e q u e n cy i n a n o n l i n e a r m a n n e r a s t h e m o l e % C H C 13 /C C 1 4 isincreased ( see Figure 12 .10) .

T ab le 1 2 .2 0 l i s ts I R d a t a an d a ss ig n m e n t s f o r T 3 on e in 1 % wt . /v o l , so lu t io n s in v a r io u sso lv en t s ( 2 0 ). I n t h e se 1 8 so lv en ts , Vop ( C = O ) 3 r an g es f r o m 1 7 0 3 .2 c m - 1 in h ex an e to1693 .3 c m - 1 in d im eth y l su l fox ide . In the case o f the four a lcohols , Vop (C =O ) 3 exh ib i ts bo thVop ( C = O ) 3 an d Vop ( C - O ) 3 . - - HO R. T h e f o r m er o ccu r s i n t h e r an g e 1 7 0 1 .5 - 1 7 0 3 .5 cm - 1 an dth e l a t t e r i n t h e r an g e 1 6 8 8 - 1 6 9 0 .6 c m - 1 . F ig u r e 1 2 .1 1 sh o ws a p lo t o f t h e Vop ( C = O ) 3f r eq u en cy f o r T 3 o n e v s t h e so lv en t a ccep to r n u m b er ( AN) . T h e so l id t r i an g le s sh o w th e d a t ap o in t s f o r t h e T 3 o n e - - - HOR m o lecu le s ; t h e so l id sq u a r e s sh o w th e d a t a p o in t s f o r T 3 o n em o l e c u l e s n o t i n t e r m o l e c u l a r l y h y d r o g e n b o n d e d i n s o l u t i o n s u r r o u n d e d b y i n t e r m o l e c u l a r l yh y d r o g en - b o n d ed a l co h o l m o lecu le s . P r o j ec t in g th e se p o in t s o n to th e b r o ad l i n ea r l i n e sh o wsth a t t h e AN v a lu es f o r t h e a l co h o l s wh en n o t h y d r o g en b o n d ed to so lv en t m o lecu le s a r e v e r ys im i l a r t o t h e AN v a lu es f o r a lk yl e th e rs . T h e AN v a lu es a r e n o t a p r ec ise m easu r e o f th e so lu t e -so lv en t i n t e r ac t io n , a s t h ey d o n o t a ccu r a t e ly acco u n t f o r s t e r i c e f f ec t s b e tween so lu t e an dso lv en t , o r d o n o t d i s t i n g u i sh b e tween m o lecu le s t h a t a r e o r a r e n o t i n t e r m o lecu la r ly h y d r o g enb o n d e d ( 2 0 ) .

R E F E R E N C E S1. Nyquist , R.A. (1984). The Interpretation o f Vapor-phase Infrared Spectra: Group Frequency Data, Philadelphia: Sadt ler

Research Laboratories, Division of Bio-Rad Inc.2. Richards, R.E. and Th om pson, H .W. (1947). J. Chem . Soc. London, 1248.3. Brown, T i . , Regan, J .E. , Scheutz, D.R., and Sternberg, J . (1959). J. Phys. Chem., 63, 1324.4. Lin-Vien, D., Cotth rup , N.B ., Fateley, W.G., and G rasselli, J.G. (1 991). The Handbook of Infrared and Raman Char-acteristic Frequencies of Organic M olecule, San Diego: Academic Press, Inc.5. McLachlan, R.D. and N yquist , R.A. (1964). Spectrochim. Acta, 20, 1397.6. Nyquist , R.A. (1963). Spectrochim. Acta, 19, 509.


19/54

Variables in Data Interpretation 2317. Nyquist, R.A. (1963). Spectrochim. Acta, 19, 1595.8. Russell, R.A. and Thompson, H.W (1956). Spectrochim. Acta, 8, 138.9. Moccia, R. and Thompson, H.W (1957). Spectrochim. A cta, 10, 240.

10. Klemperer, W., Cronyn, M., Maki, A., and Pimentel, G. (1954). J. Am. Ch em. Soc. , 76, 5846.11. Thompson, H.W. and Jameson, D.A. (1958). Spectrochim. Acta, 13, 236.12. Nyquist, R.A., Chrisman, R.W., Putzig, C.L., Woodward, R.W., and Loy, B.R. (1979). Spectrochim. Acta, 35A, 91.13. Nyquist, R.A. and Luoma, D.A. (1991). App l. Spectrosc., 45, 1501.14. Nyquist, R.A. and Luoma, D.A. (1991). App l. Spectrosc., 45, 1491.15. Nyquist, R.A. and Luoma, D.A. (1991). Appl. Spectrosc., 45, 1497.16. Nyquist, R.A., Putzig, C.L., and Clark, T.D. (1996). Vib. Spectrosc., 12, 81.17. Gutmann, V. (1978). The D onor-acceptor Approac h to Molec ular Interactions, p. 29, New York: Plenum Press.18. Nyquist, R.A. and Fiedler, S.L. (1995). Vib. Spectrosc., 8, 365.19. Nyquist, R.A. (1990). Appl. Spectrosc., 44, 215.20. Nyquist, R.A., Puehl, C.W, and Putzig, C.L. (1993). Vib. Spectrosc., 4, 193.


20/54

'

._-w

I

(3=E

j~>.(..)1~

,

I00

9

~-

z

o

\

0

0

0

0

o

0

LD

~

~

to

0w

-

to

~

to

to

to

to

to

to

to

to

to

(LUO)HN~CI~ONO84NNINIXVNNOIdOS

0

0

~

d

~

N

~

o

~

d

~

0~

0

z

~

o

~

U

~

d

.~

0

=LI0

~D

I

z0.~

O

O-Otore


21/54

t~t~t~L|zt~t~oot~zzGzobI

ooe


22/54

234 Carboxamides , Ureas , Th iou reas , lmidazo l id inones , Ca f fe ine , I soca f fe ine , Urac i l s , lmides , e t c .

0II XA - O . O 0 2 M i n C H C I 3 y / C ~ N , , ~ "B = 0 . 0 0 2 M o r l e s s i n C C I 4 IH

+ . 8

+ . 7

)

Y = C H 2 B r Y = C H 3 Y = C C I 3A B A B A B

~ .

+ . 5 iA ~+ . 3I q q

+ . 2 i ~r

i

. i () )J0 > L_= = ' . l

)- - . 2

- . 6 , , . . . . . . . i , , ~ ~ , ,,1 6 6 5 1 6 7 5 16 8 5 1 6 9 5 1 7 '0 5 1 6 8 0 1 6 9 0 1 7 0 0 " 1 7 " 1 0 1 7 2 0 1 7 1 5 1 7 2 5

~c=o

r 0 2 e 13

I I___,.o(C O)C H 9 I O/ / Ie 9

B r l i 7CI

F 9 6~________~ $ 5H 4

CH 3 9Io - e l l 3 |

N -( - C 2 H 5 ) 2l 1 "

1 7 3 5 ' 1 7 4 5

FIGUR E 12 .3 P lo t s o f the vC- -O f r equenc ie s for ~ -b romo-p -x -acetan i l ide , p -x -ace tan i l ide , and ~ ,~ ,~ - t ri ch lo ro -p -x -acetani l ide in 0 .002 M solu t ions or less in CC14 and CHC13 vs Ha mm ett a e values .


23/54

O

"~

Z

"I"

C)

o

~O=

I

o=o

o=~

z

I

I

~

T

1"

o

o

~

IZI

O

~Bv

I

,I

J

J

.,I

I

I

I

I

I

O

O

O

O

O

O

O

O

O

O

OO~

OGO

p,-=,

OOI.OO

CO

I

O

_

CO

tO

O~D

O.v=-

OOo.-4

Op.

o~~o

91LOOi

90Ol:IOH0

%el011~


24/54

"0sS

F,

1o!

I

\

g

.

O

~oe"

O

to

_

1I

:

:

:

:

t~

O

I

o

In

o

~

t~.~

a.~"

~v

.9

r=O.=c9I9UI

t~~O

r-

to

O


25/54

r

i.0

w

%

%

%

%

~

0

%

~

'~

-

.

9

~,

',

.

.

.%'

"

~O

F-

~

.~

"

,

I

.....

I

.....

I...

I

'

I

'-I

I......

~

~

~

o

~

o

~

o

e

oo,4A9Ioo


26/54

/%/

0~x

o

i

o

I~

v

o

O

o

o

~

~O.=

O14t~|e

!ct~t~t~,a,4

9ILOOreP4L


27/54

V a r i a b l e s i n D a t a I n t e r p r e t a t i o n 239100

9 O8 Oq 70(3

oo 50"-J 4 0 -

2 o -l O -

o1 6 9 5 . 6

R - N N - RO. l. . ~ J . 0 R I . CHz ' C H CH=N T z O N EiR

I I = = | I1 6 9 6 . 0 1 6 9 6 . 4 1 6 9 8 . 0 1 6 9 8 . 4

I I I i I1 6 9 6 . 8 1 6 9 7 . 2 1 6 9 7 . 6v O0 P(C = O)=,cm"

F I G U R E 1 2 . 8 A p l o t o f V op ( C = O ) 3 f o r t r i a l l y l - l , 3 , 5 - t r i a z i n e - 2 , 4 , 6 - ( 1 H , 3 H , 5 H ) t r i o n e ( T 3 o n e ) v s m o l e % C H C 1 3 / C C 1 4.

F I G U R E 1 2 .9

1 0 0 -9 O8 0,q. 70(3

(3z

3o20lOo1 4 5 5 . o

,o, /R - N ' ~ " ' ~ N - R T = O N E J

1 ! . I I I I i _ _ J1456.0 1457.0 1458.0 1459.0v OO P(C3N3),cm 1

A plot of Vop (C3N3) for t r i a l l y l - l , 3 , 5 - t r i a z i n e - 2 , 4 , 6 - ( 1 H , 3 H , 5 H ) t r i o n e ( T 3 o n e ) v s m o l e % C H C 1 3 / C C 1 4 .

F I G U R E 1 2 . 1 0CH C1 3 / CC1 4 .

8O,q, 70O--~ 60(3-rO 5O-~ 4o-

2 0 -1 0 -09 2 9 . 5

oR - N N - R

!R

- ~

I I I !9 3 0 . 5 9 3 1 . 5 C = C H = W A G , c m " I

R I I CH, = CH-CH=

! I , I !9 3 2 . 5 9 3 3 . 5 9 3 4 . 5

A p lo t o f C = C H 2 w a g f o r t r i a l l y l - l , 3 , 5 - t r i a z i n e - 2 , 4 , 6 - ( 1 H , 3 H , 5 H ) t r i o n e ( T 3 o n e ) v s m o l e %


28/54

240 Carboxam ides, Ureas, Thioureas, lmidazolidinones, Caffeine, lsocaffeine, Ura cils, Imides, etc.4 5 R i s C H = = C H - C H 2

3025 L_ 9 RepresentZ< R O H: O = C20 - Com p lexes1 5 -1 0 -5 -0 I1 6 8 8

oR - N N - R

IR

In (ROH:O - R )So lu t ion

F o r ~G r o u p s \Not in ter - dmo lecu ledyH - B o n d e d

i ~ i J , i . . . . 9 i " ~ ~1690 1692 1694 1696 1698 1700 1702 1704V OOP(C=Oh. cm"

FIGURE 12. II A plot of Vop (C--O)3 and Vop (C =O )3 ... HO R for triallyl-l,3,5-triazine-2,4,6-(1H,3H,5H) trione vs thesolvent acceptor number (AN).


29/54

V a r i a b l e s i n D a t a I n t e r p r e t a t i o n 241T A B L E 1 2 . 1 A c o m p a r i s o n o f p r i m a r y , s e c o n d a r y , a n d t e r t i a r y a m i d e s i n v a r i o u s p h y s i c a l p h a s e s

P r i m a r y a m i d ea s s i g n m e n t s

V a p o r p h a s e V a p o r p h a s e N e a t p h a s e I n t e r m o l e c u l a r[Ref . 1 ] [Ref . 1 ] no nb on ded H-b ond ed

R - ( C = O ) N H 2 C 6 H s - ( C = O ) N H 2 [ R ef s. 2 ,3 ,4 1 [ R ef s. 2 , 3 ,4 ]c m - 1 c m - 1 c m - 1 c m - 1

asym .NH 2 s t r .s y m . N H 2 s t r.C---O str.N H 2 b e n d i n gC - N s t r .N H 2 r o c kN H 2 w a gN - C = O i n -p l a ne b e n d

3 5 4 8 - 3 5 6 5 3 5 5 6 - 3 5 4 03 4 3 0 - 3 4 4 4 3 4 3 5 - 3 4 4 81 7 3 2 - 1 7 8 0 1 7 1 9 - 1 7 3 1 . 11 5 7 6 - 1 6 0 0 1 5 8 6 - 1 6 0 01 3 0 8 - 1 4 0 0 1 3 4 1 - 1 3 5 5

c a . 3 5 2 0c a . 3 4 0 0

1 6 7 5 - 1 7 1 51 5 8 5 - 1 6 2 01 3 9 0 - 1 4 3 01 1 0 0 - 1 1 5 0

5 5 0 - 6 0 0

3 3 5 0 - 3 4 7 53 1 6 0 - 3 3 8 51 6 4 0 - 1 6 8 01 6 2 0 - 1 6 4 01 3 9 0 - 1 4 3 01 1 0 0 - 1 1 5 0

6 0 0 - 7 5 0 *25 5 0 - 6 0 0

S e c o n d a r y a m i d e a s s i g n m e n t s Vapor phase .3 N e a t p h a s e n o n b o n d e d- 1c mH - b o n d e d

C 1 - 1

NH s t r . , t ransci s[5 M .R.] .4[6 M.R.I[7 M.R.]

C--O s t r .C--O s t r . [4 M.R. ]C--O s t r . [5 M.R. ]C=O s t r . [6 M.R. ]C= s t r . [7 M.R. ]C N H s t r . - b e n d , t r a n s

, c i sC N H s t r . - o p e n , t r a n s

,cis

3 4 1 6 - 3 4 1 93 4 7 83 4 3 83 4 4 2

1 6 9 8 - 1 7 2 0175917151711

3 4 0 0 - 3 4 9 03 2 0 0

1 6 5 0 - 1 7 0 0

1 5 0 0 - 1 5 5 0ca. 1450

1 2 0 0 - 1 2 5 0ca .1350

3 3 0 0

1 6 3 0 - 1 6 8 01 7 3 0 - 1 7 8 01 7 0 0 - 1 7 5 0

1 5 1 0 - 1 5 7 01 4 0 0 - 1 4 9 01 2 5 0 - 1 3 1 01 3 1 0 - 1 3 5 0

T e r t ia r y a m i d e a s s i g n m e n t sC = O s t r . 1 6 7 1 - 1 7 3 1 1 6 3 0 - 1 6 8 0. 1 See text .,2 Broad.,3 See text .* 4 M . R . = m e m b e r e d r i n g o r l a c t a m .


30/54

2 4 2 Carboxamides , Ureas , Thioureas , Imidazol id inones , Caffe ine , Isocaffe ine , Uraci ls , Imides , e tc .T A B L E 1 2 . 1 A T h e N H s t re t c h i n g f r e q u e n c i e s a n d a b s o r b a n c e d a t a fo r N - m e t h y l a c e t a m i d e i n c o n c e n t r a t i o n r a n g i n gf r o m 1 . 3 7 x 1 0 - 3 t o 1 . 3 7 m o l / l i t e r i n C C I4 s o l u ti o nC o n c e n t r a t i o n A p p a r e n tm o l e / l i t e r B a n d i n t e n s it yN - m e t h y l a c e t a m i d e N - H s tr . A h a l f w i d t h % B o n d e d B x 1 0 ( 7 )0 . 0 0 1 3 7 3 4 7 6 0 . 1 9 9 6 . 8 0 3 . 60 . 0 0 3 4 2 3 4 7 5 0 . 4 2 6 7 1 1 3 . 20 . 0 0 6 8 5 3 4 7 5 0 . 8 1 7 .1 1 5 30 . 013 7 347 5 1 . 48 7 . 1 19 2 . 90 . 0 3 4 2 3 4 7 5 2 . 8 7 7 . 4 2 7 2 . 20 . 6 8 5 3 4 7 4 3 . 9 9 7 . 3 5 6 1 . 60 . 1 3 7 3 4 7 4 4 . 9 3 7 . 4 7 3 0 . 9 60 . 3 4 2 3 4 7 2 6 . 6 3 7 . 4 8 6 0 . 5 20 . 6 8 5 3 4 7 2 7 . 1 7 . 1 9 2 0 . 2 81 . 027 3471 8 . 1 7 . 4 94 0 . 211 . 37 3471 8 . 88 7 . 4 95 0 . 17N - m e t h y l c h l o r o a c e t a m i d e0 . 0 0 9 2 1 3 4 5 0 0 . 1 9 7 6 . 4 1 4 . 90 . 0 2 3 3 4 5 0 0 . 4 7 9 6 . 4 4 4 . 80 . 0 4 6 3 4 5 0 0 . 8 9 7 6 . 4 1 0 4 . 50 . 0681 3451 1 . 28 6 . 5 12 4 . 40 . 0921 345 0 1 . 63 6 . 9 12 4 . 40 . 1 8 4 3 4 5 0 2 . 6 7 . 2 2 6 3 . 70 . 2 3 3 4 5 0 3 . 0 4 7 . 5 2 8 3 . 60 . 2 7 6 3 4 4 9 3 . 4 1 7 . 5 3 3 3 . 30 . 3 6 8 3 4 4 9 3 . 8 6 8 3 9 3 . 60 . 4 6 3 4 4 9 3 . 9 7 8 . 2 5 0 2 . 50 . 5 5 3 3 4 4 9 4 . 3 1 8 . 5 5 2 2 . 40 . 691 344 8 4 . 37 9 . 1 58 2 . 10 . 7 2 7 3 4 4 8 4 . 6 5 9 . 1 5 8 2 .10 . 8 2 9 3 4 4 7 4 . 8 9 9 . 2 6 1 20 . 9 2 1 3 4 4 8 4 . 9 5 9 . 3 6 4 1 .8

T A B L E 1 2 . 1 B T h e N H s t r e t c h i n g , C - - O s t r e t c h i n g , a m i d e I I , a n d a m i d e I I I f r e q u e n c i e s f o r N - m e t h y l a c e t a m i d e i nC H B r 3 s o l u t i o n sC o n c e n t r a t i o n m o l e / l i t e r [ C H B r 3 ]N - m e t h y l a c e t a m i d e N - H s tr . N - - H s tr . b o n d e d C - - O s tr . A m i d e I I A m i d e I I I0 . 0 0 6 8 5 3 4 5 6 1 6 6 8 1 5 3 1 1 2 7 80 . 0 2 7 3 4 5 6 1 6 6 8 1 5 3 1 1 2 7 90 . 1 3 7 3 4 5 7 1 6 6 8 1 5 3 2 1 2 7 80 . 6 8 5 3 4 5 7 3 3 2 5 1 6 6 0 1 5 3 7 , 1 5 6 0 1 2 7 92 . 0 5 3 4 5 4 3 3 2 0 1 6 5 6 1 5 6 1 1 2 7 92 . 7 4 3 4 5 1 3 3 0 5 1 6 4 9 1 5 6 3 1 2 7 9


31/54

V a r i a b l e s i n D a t a I n t e r p r e t a t i o n 2 4 3TABLE 12.1C The overtone for amide II of N-met hyl acetamide and N-met hyl chloroaceta mide in varyingconcentrations in CCI4 solutionsConcentration mole/liter [CC14]N-methyl acetamide 2(amide II) A Band halfwidth Intensity Bx 10(8)

0.342 0.02 30 0.60.0685 3102 0.059 28 90.137 3103 0.206 30 160.342 3104 0.775 30 250.685 3105 1.65 31 261.027 3104 2.76 30 291.37 3105 3.55 30 28N-methyl chloroacetamide0.276 3098 0.049 26 1.70.46 3098 0.33 26 6.70.553 3098 0.46 26 7.80.727 3098 0.82 27 10.50.829 3099 0.93 27 110.921 3099 1.38 28 15


32/54

2 4 4 Carboxamides , Ureas , Th ioureas , Imidazo l id inones , Caf fe ine , l soca f fe ine , Urac i l s , Imides , e tc .TABLE 12 .2 IR da ta and a s s ignm en ts fo r N-a lky l ace tamide s , and N-a lky l 0~- subs t i tu t ed ac e tamid es in d i lu te so lu te s

2 ( C- - O s tr .) N - H CCNCom pou nd ace tamide N -H s tr . A .1 C- -O s tr . o r c i s N -H s tr . bend ing s tr .N-m e thy l 3478 21 .5 1688 3365N-e thy l 3462 16 .2 1688 3360N-propy l 3461 18 .5 1690 3360N-n-bu ty l 3460 18 .1 1688 3 360N- i sobu ty l 3471 21 .7 1689 3365N- i sop ropy l [vapor ] 3460(0 .051) 1714(1 .240) 3420(0 .020)N- i sop ropy l 3451 18 .9 1687 3360N-s -bu ty l 3450 23 .2 1685 3360N- t -bu ty l 3453 25 .4 1688 3360N-phen y l 3449 34 .6 1708 34000t-chloro-acetamideN-n-bu ty l 3433 30 .9 1684 3 348N- i s

Date post:	03-Apr-2018
Category:	Documents
Upload:	mani-pillai
View:	218 times
Download:	0 times

Ureas Thioureas in detail for study

Documents