tracers. The exchange results are expected to throw light on the lability of the complex. This information could also be utilised to carry out metal ion detoxi- fication. Hence, results relating to metal ion exchange are presented in this note.' Cobalt chloride (BDH, AR), thiourea (Budapest, Hungary), ammonium thiocyanate (BDH, AR), acetone (BDH, AR) and amyl acetate (BDH) were used. The dithiocyanato-bis(thiourea)cobalt(II) com'J plex was prepared according to the method described by Nardelli- and the composition established by elemental analyses. Isotope exchange data were obtained at two con- centrations, viz. 0.5 X 10- 2 and 2.5 X 10- 2 M of cobalt chloride, keeping the concentration of the complex constant (0.5 X 10- 2 M). The solutions were prepared and the reaction mixture contained equal volumes of both the reactants. The reaction mix- tures were equilibrated at 30 0 ± 0.1. 60 Co tracer (500 Mrad) was added to the reaction mixture. The separation of the free cobalt from the complex was effected by adding a mixture of amyl acetate (2 ml) and water (1.5 ml) to an aliquot (2 ml) of the reaction mixture withdrawn periodically. The free cobalt was extracted into the aqueous layer and the activity of the separated free cobalt solution was measured with a y ray spectrometer of type, GRS 20 B supplied by Trombay Electronic Instruments. The course of the exchange was followed by measuring activity as a function of time. The isotope exchange data at two different concen- trations of cobalt chloride are given in Table 1. Frac- tion exchange (F) was calculated by the relation, F = SAT-SAO/SArX) - SAO,where SAOSATand SAoo denote the specific activity of cobalt chloride at times 0, t and 00 respectively. Errors in pipetting and counting contribute to an uncertainity of ± 0.01 % in F values. The half-time (t]/2) of the exchange was obtained by both the graphical and least-square methods. The maximum difference between t]/2 values obtained by the two methods was found to be two times the experimental error. The t1/2 values obtained by least-square method at cobalt chloride concentrations 0.5 X 10- 2 and 2.5 X 1Q-2M are 30.8 min and 24.2 min respectively. TABLE 1. ISOTOPE EXCHANGE DATA OF Co (II) IN DITHIO- CYANATO BIS (TffiOUREA) COBALT (II) COMPLEX [Cone. of Complex = 0.5 x. 10- 1 M] Time F (&) Time F(b) min min 0 0 2 0.44 2 0.15 12 0.53 10 0.28 20 0.62 20 0.43 40 0.66 30 0.61 50 0.78 45 0.70 62 0.88 85 0.92 80 0.90 110 0.96 116 0.99 (a) Cobalt chloride cone. = 0.5 x 10- 1 M: (b) cobalt chloride cone. = 2.5 X 1O~1 M NOTES The rate of exchange (R) was calculated using McKay's relation" R = 0.693. [A] [B] t112 [A] + [B] where [A] and [B] are the concentrations of the complex and free cobalt. The values of R at cobalt chloride concentrations of 0.5 X 10- 2 and 2.5 X 1Q-2M come out to be 5.6 X 10- 5 and 1.7 X 10- 4 mol litre- 1 min=. . The rates of exchange show that the complex is labile in the kinetic sense. The lability may be as- cribed to the geometry of the complex and to the nature of the metal ligand bond. The tetrahedral configuration assisgned to the complex on the basis of magnetic data shows that the complex is para- magnetic in character. Such complexes are expected to be labile in nature. Further the observed lability suggests that the sulphur-metal ion bond is weak and also partially ionic in character. The authors are grateful to Dr M. V. P. Rao for his help in the analysis of the results. References 1. MOHARANA, S. N. & DASH, K. S., Indian J. Chem., 8 (1970), 1023. 2. NARDELLI, M., CAVALCA, L. & FAVA, G., Gazz. chim. ital., 87 (1957), 1209. 3. WAHl, A. C. & BONNER, N. A., Radioactiviiy applied to chemistry (John Wiley, New York), 1951. Studies on Triarylantimony Dicarboxylates KANAK BAJPAI, R. SINGHAL & R. C. SRIVASTAVA* Department of Chemistry, Lueknow University, Lueknow Received 19 October 1978; accepted 16 January 1979 A series of triarylantimony dicarboxylates of thet ype Ar sSb- (OOCR).[Ar=CeHa or p-CHaCeH, and R=H, CH 2 C!, CH 2 Br, CC!., C 2 HIi, CaH" C e H Ii CH 2 , CeHaCH=CH, CHsCH=CH, CH3(CHa)1, CHa(CH a )l8J CH 3 COCH.CH •• o-or m-CHsC.H.- OCH I and p-CIC a H 4 0CH 2 ] has been prepared by a metathetical reaction and characterised. These carboxylates are monomeric in benzene and non-conducting in acetonitrile solution. A few representative compounds have been examined for their insecticidale behaviour also. ORGANOANTIMONY(V) derivatives of formic-", benzoic', acetict's, propionic, hal0 4 '5 and cyano- acetic" acids have been prepared by the reaction of organoantimony halides with (i) the corresponding silver carboxylate or (ii) silver oxide and carboxylic acid. Effect of substituents on the Sb-OOCR' bond has been studied with the help of IR and NMR spectroscopy+". While the present work was in progress a paper describing preparation and spectro- scopic studies of triorganoantimony derivatives of substituted benzoic acids appeared", No study however seems to have been made on their biocidal activity. We have now synthesised a series of triarylantimony derivatives of formic, monochloro- acetic, monobromoacetic, trichloroacetic. propionic- butyric, phenylacetic, cinnamic, crotonic, pelargonic, stearic, levulinic, 0- or m-methylphenoxyacetic or p-chlorophenoxyacetic acids by a more convenient 73
Transcript
tracers. The exchange results are expected to throwlight on the lability of the complex. This informationcould also be utilised to carry out metal ion detoxi-fication. Hence, results relating to metal ion exchangeare presented in this note.'
Cobalt chloride (BDH, AR), thiourea (Budapest,Hungary), ammonium thiocyanate (BDH, AR),acetone (BDH, AR) and amyl acetate (BDH) wereused. The dithiocyanato-bis(thiourea)cobalt(II) com'Jplex was prepared according to the method describedby Nardelli- and the composition established byelemental analyses.
Isotope exchange data were obtained at two con-centrations, viz. 0.5 X 10-2 and 2.5 X 10-2 M ofcobalt chloride, keeping the concentration of thecomplex constant (0.5 X 10-2 M). The solutions wereprepared and the reaction mixture contained equalvolumes of both the reactants. The reaction mix-tures were equilibrated at 300 ± 0.1. 60Co tracer(500 Mrad) was added to the reaction mixture.The separation of the free cobalt from the complexwas effected by adding a mixture of amyl acetate(2 ml) and water (1.5 ml) to an aliquot (2 ml) of thereaction mixture withdrawn periodically. The freecobalt was extracted into the aqueous layer andthe activity of the separated free cobalt solutionwas measured with a y ray spectrometer of type, GRS20 B supplied by Trombay Electronic Instruments.The course of the exchange was followed bymeasuring activity as a function of time.
The isotope exchange data at two different concen-trations of cobalt chloride are given in Table 1. Frac-tion exchange (F) was calculated by the relation,F = SAT-SAO/SArX)- SAO,where SAO SATand SAoodenote the specific activity of cobalt chloride at times0, t and 00 respectively. Errors in pipetting andcounting contribute to an uncertainity of ± 0.01 %in F values. The half-time (t]/2) of the exchange wasobtained by both the graphical and least-squaremethods. The maximum difference between t]/2 valuesobtained by the two methods was found to be twotimes the experimental error.
The t1/2 values obtained by least-square methodat cobalt chloride concentrations 0.5 X 10-2 and2.5 X 1Q-2M are 30.8 min and 24.2 min respectively.
TABLE 1. ISOTOPE EXCHANGE DATA OF Co (II) IN DITHIO-
(a) Cobalt chloride cone. = 0.5 x 10-1 M: (b) cobalt chloridecone. = 2.5 X 1O~1M
(
NOTES
The rate of exchange (R) was calculated using McKay'srelation"
R = 0.693. [A] [B]t112 [A] + [B]
where [A] and [B] are the concentrations of thecomplex and free cobalt. The values of R at cobaltchloride concentrations of 0.5 X 10-2 and 2.5 X 1Q-2Mcome out to be 5.6 X 10-5 and 1.7 X 10-4 mol litre-1
min=. .The rates of exchange show that the complex is
labile in the kinetic sense. The lability may be as-cribed to the geometry of the complex and to thenature of the metal ligand bond. The tetrahedralconfiguration assisgned to the complex on the basisof magnetic data shows that the complex is para-magnetic in character. Such complexes are expectedto be labile in nature. Further the observed labilitysuggests that the sulphur-metal ion bond is weak andalso partially ionic in character.
The authors are grateful to Dr M. V. P. Rao forhis help in the analysis of the results.
References1. MOHARANA, S. N. & DASH, K. S., Indian J. Chem., 8 (1970),
1023.2. NARDELLI, M., CAVALCA, L. & FAVA, G., Gazz. chim. ital.,
87 (1957), 1209.3. WAHl, A. C. & BONNER, N. A., Radioactiviiy applied to
chemistry (John Wiley, New York), 1951.
Studies on Triarylantimony Dicarboxylates
KANAK BAJPAI, R. SINGHAL & R. C. SRIVASTAVA*
Department of Chemistry, Lueknow University, Lueknow
Received 19 October 1978; accepted 16 January 1979
A series of triarylantimony dicarboxylates of thet ype Ar sSb-(OOCR).[Ar=CeHa or p-CHaCeH, and R=H, CH2C!, CH2Br,CC!., C2HIi, CaH" CeHIiCH2, CeHaCH=CH, CHsCH=CH,CH3(CHa)1, CHa(CHa)l8J CH3COCH.CH •• o-or m-CHsC.H.-OCHI and p-CICaH40CH2] has been prepared by a metatheticalreaction and characterised. These carboxylates are monomericin benzene and non-conducting in acetonitrile solution. A fewrepresentative compounds have been examined for their insecticidalebehaviour also.
ORGANOANTIMONY(V) derivatives of formic-",benzoic', acetict's, propionic, hal04'5 and cyano-
acetic" acids have been prepared by the reaction oforganoantimony halides with (i) the correspondingsilver carboxylate or (ii) silver oxide and carboxylicacid. Effect of substituents on the Sb-OOCR' bondhas been studied with the help of IR and NMRspectroscopy+". While the present work was inprogress a paper describing preparation and spectro-scopic studies of triorganoantimony derivatives ofsubstituted benzoic acids appeared", No studyhowever seems to have been made on their biocidalactivity. We have now synthesised a series oftriarylantimony derivatives of formic, monochloro-acetic, monobromoacetic, trichloroacetic. propionic-butyric, phenylacetic, cinnamic, crotonic, pelargonic,stearic, levulinic, 0- or m-methylphenoxyacetic orp-chlorophenoxyacetic acids by a more convenient
73
INDIAN J. CHEM., VOL. 18A, JULY 1979
The reactions proceed under mild conditions andare generally quantitative (yield; 70-90 %). All thecompounds are colourless solids with sharp meltingpoints and monomeric in freezing benzene. They areunaffected by atmospheric moisture; the meltingpoint of a sample of Ph3Sb(OOC-CH=CHC6Hs)2did not change even after stirring (2 hr) with waterat room temperature. Molar conductances of their10-3M solutions in acetonitrile range between 30 and35 ohm-1 mol? em- at 30° which shows their non-ionic characters.
Infrared spectra were recorded in KBr/nujol in theregion 4000-400 cm" with Perkin-Elmer 337 spectro-photometer. The asymmetric and symmetric COOstretching modes of triarylantimony dicarboxylates(Table 1) were identified by comparison with thereported values for the carboxylic acids and theirsodium salts",
The non-conducting nature of these derivatives inacetonitrile and the absence of evidence for carboxy-late ions in the IR spectra rules out the possibilityof ionic structure and suggest the. presence of estertype of RCOO groups. The bands due to the arylgroups are almost identical with those observed forthe corresponding dihalides".. PMR spectra of (p-CHaC6H4)3Sb(OOCCH2Ph){l
showed a multiplet centered at 2.70 l' (due to ph andp-CH3C6H4) and two singlets at 6.62 and 7.65 l' (dueto CH2 and CH3 protons respectively) with an intensityratio of22:4:9 which suggests that both the carboxylategroups are equivalent.
Thus the general features of IR and NMR spectraof these triorganoantimony dicarboxylates are consis-tent with a trigonal bipyramidal structure containinga planar AraSb moiety. A similar structure has beenestablished in the cases of'triorganoantimony dihalidesand triphenylantimony dimethoxide on the basis ofIRZ'4 and X-raylO. evidences respectively.
74
,(
TADLEI-ANALYTICAL AND IR DATA OF TRIARYLANTIMONYDICARBOXYLATES[ArsSb(OOCR),J
m.p.eC)
Found (calc.), %
method. Some observations on the insecticidalactivity of these carboxylates are also reported.
Carboxylic acids were purified by distillation orrecrystallization. Triphenyl-and tri-p-rolylantimonydibromides were prepared by reported methods'. R
General method of preparation of friary/antimonydicarboxylates - Triphenylantimony dibromide (ortrl-p-tolylantimony dibromide) (2 mmole), carboxylicacid (4 mmole) and triethylamine (2 ml) were stirred ••together in benzene (is ml) at room temp~rature for CCI2-3 hr and then refluxed for 2 hr. Triethylamine •hydrobromide was filtered off and the filtrate on CH.CHzconcentration in vacuo afforded triarylantimonydicarboxylates which were recrystallised from petro- (CHS)2CH
leum ether (40-60°) or acetonitrile/ petroleum ether CeH.CH=CH 192(often oily product was obtained which soldified onscratching with a glass rod and cooling). CHaCH=CH 146
The reaction of triarylantimony dibromides withcarboxylic acids in presence of triethylamine afforded CHs(CH')18a series of triarylantimony dicarboxylates (Eq. 1).
Typical methodt! of application by micrometersyringe was employed to test the toxicity of threerepresentative compounds on adult male and femalecockroaches. Mean knock down time (in hr) for0.1 % concentrations of (p-CH3C6H4)aSb(OOCCI3)2,(C6Hs)aSb(OOCCHzCH2COCH3)z(C6Hs)3Sb(OOCCH=CHCHa)2 parathion (control) and acetone are 13,12, 12,6.5 and 40 respectively. The correspondingvalues for 0.5 % concentration of the reagents are 11,10,9,4 and 40 respectively. The compounds examinedappear to be only moderately active and the activityis not significantly affected by the nature of the Ar orR group. Fungicidal activity of these new carboxylates is being examined.
One of us (R. Singhal) is thankful to the CSIR,New Delhi for the award of a junior research fellow-ship.
References1. GOEL, R. G., Call. J. Chem., 47 (1969), 4607.
2. Smuno, M. & OKAWARA, R., 1. organometal. Chem., 5(1966), 537.
3. DOAK, G. 0., LONG, G. G. & FREEDMAN, L. D., 1. organa-metal. Chem., 4 (1965), 82.
4. GOEL, R. G., MASLOWSKY, Jr.,.E. & SENOFF, c. V., Inorg.nucl. chem. Lett., 6 (1970), 833; Inorg. Chem., 10 (1971),2572.
5. GaEL, R. G. & RIDLEY, D. R., 1. organometal. Chem.,38 (1972), 83.
6. Oucm, A., NAKATANI, M., TAKAHASm, Y. KITAZlMA, S.,SUGIHARA, T., MATSUMOTO, M., UEIDRO, T., KITANO, KKAWASHIMA, K. & HONDA, H., Chem. Abstr., 86 (1977),5561.
7. LILE, W. J. & MENZIES, R. S., J. chem. ss«, (1950), 617.8. GREAY, W. J., Coord. Chem. Rev., 7 (1971), 110.9. SPINNER, E., J. chem. Soc., (1964), 4217.
10. BROOKS, C. J. W., EUNTON, G. & NORMAL", J.F., J. chem,Soc., (1961), 106.
11. NASH, R., Ann. Appl. Biol., 41 (1954), 652.
Molar Adducts of Dimetbyldichlorosilane with SchiffBases
(Miss) J. K. KOACHER, J. P. TANDON* & R. C. MEHROTRAt
Department of Chemistry, University of Rajasthan,Jaipur 302 004
Received 19 October 1978; revised and accepted 1 February 1979
(CHa)aSiCl2.2L and (CHa)aSiCI2L' type of molar adducts havebeen synthesized by the reactions of dimethyldichlorosilane withdifferent types of schiff hases. The resulting derivatives havebeen characterized on the basis of elemental analyses, conduct-ance measurements and IR and I'IMR. spectral studies.
THE silicon in silicon halides and halogenosilanestends to behave as a typical acceptor':", forming
more stable coordinate links with donor atoms fromthe first row of the Periodic Table. Orlova et al",investigated the reactions of SiCl4 with hydroxyanilsof the type RC6H4CH:NCaH3R'(OH) with a view toobtaining thermally stable polymers, and synthesizedcomplexes of the type SiCI4.2L having a trans-octa-hedral geometry. The present paper describes thesynthesis of 1:2 and 1:1 adducts of dimethyldichloro-silane with schiff bases of the types (I-V)
YR,C2 H5, n - C3H7, iso -C3H7' n -C4 Hg,o-C6H4CH3,
m-~H4CH3.P-C6H4CH3,o-C6H40CH3,m-~H40C~
ond p-~H40CH3
R'=-(CHz)z- and -(CHZ)3-ond
X = -(CHZ)2 - ond - (CH2)3-
tPresent address : Vice-Chancellor, University of Delhi,Delhi, 110007
NOTES
All reactions were carried out under completelyanhydrous conditions. Dimethyldichlorosilane wasdistilled at 70° and DMF was purified as reportedearlier", Dried and distilled benzene (BDH) wasused. "
The following method for the estimation of siliconwas adopted on account of the higher volatility andcomparatively stable nature of carbon-silicon bond".
The sample (0.1 to 0.3 g) was added to AR H2S04(30 ml), cooled and 5 g each of solid ammoniumsulphate (AR) and ammonium nitrate (AR) wereadded and kept overnight at room temperature andfinally digested for 4 hr. The solution was thencooled and diluted with distilled water. The precipi-tate was filtered, dried and ignited to give silica.
Schiff bases (I-V) were prepared by .refluxingaldehydes with alkyl aryl and hydroxyalkylaminesor diamines in requisite amounts in the presence ofbenzene for several hours. Water formed in thereactions was removed azeotropically. These weredistilled before use or recrystallized.
Reaction between dimetliyldichlorosilane and sali-cylidene-ethylamine - Salicylidene-ethylamine (2.5 g)w.as slowly added to a ben.zene solution of dimethyl-dichlorosilane (1.08 g) with constant shaking. Anexothermic reaction took place and the solid com-pound separated out immediately. After decantingthe solvent, the resulting solid was repeatedly washedwith benzene and product dried under reducedp~essure. Light yellow solid compound (CHa)z-SlCI2.2C9HllNO (3.45 g) in 95 % yield resulted(Found:Si, 5.00; N, 6.45; CI, 16.92. Reqd : Si,6.58; N, 6.55; CI, 16.69%).
.The details of other reactions are given in Table I.The 1:2 molar reactions of dimethyldichlorosilane
with mono-basic bidentate and bi-basic tridentateschiff bases(L) and 1: 1 molar reactions with bi-basictetradentate schiff bases(L') may be represented byEq. (I) and (2) respectively.
All the resulting derivatives are coloured solids,mostly soluble in chloroform and monomeric in nature(mol. wt in chloroform with the central metal atombeing in the hexacoordinated state. The alcoholicand phenolic protons do not appear to take part inthese reactions and all the schiff bases simply act asneutral monodentate ligands with nitrogen of theazomethine group coordinating to silicon.
Their molar conductance values in dry DMF havebeen found to be below 70 ohm'? em- mor ', indicat-ing their poor electrolytic behaviour.
In the IR spectra (vmaxin cnr") of the 'ligands, a:strong band at ,....,1625 ± 5 has been assigned to thevC=N. The coordination of the azomethine nitro-gen to silicon atom is indicated by the shift of aboveband towards higher frequency side due to an in-crease in the bond order. A strong band at 1280in the spectra of the schiff bases due to the phenolicCOOstretching vibration?", remains almost unalteredindicating the non-coordinating nature of phenoli~oxygen in these derivatives. Further, a broad andmedium band in the 3500-3300 region in the spectraof the schiff bases, due to hydrogen bonded vOH,
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