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Qualitative Analysis of Circular Dichroism Spectrum
Peking UniversityJian Deng
2007.05.31
•Exciton Theory of Circular Dichroism
•Conformational Analysis
•Qualitative analysis of CD
•ORD
•Plans
Outline
Energy Splitting
Why is energy splitting more easily observable in CD Spectrum ?
X* Y*
VXY
00
a a
X YGround State
Excited State
Local Excitation Local excitationDelocalized ExcitaionExciton
X*
Y*
1( ) �������������� ( )
��������������
( ) ��������������
sinmvr mv
qB
2 cosmvh v T
qB
0 a ����������������������������
0 ( )a ����������������������������
ia a ii
e Z r ������������������������������������������
( ) ( ) ia a ii
e Z r ������������������������������������������
Permanent dipole moment of groud state
Permanent dipole moment of excited state
Electric transition moment
N
OO
N
OO
N
OO
( / )( )i i im i c R ����������������������������
N
im��������������
im��������������
N
000i 0 0
0 00 0
R Im( )
cos( , )
ii i i
i ii i
m
m m
����������������������������
��������������������������������������������������������
Dipole Moment
small
Exciton Coupling Theory
2��������������
3��������������
23r
12
3
4
2e
3e
23e
3 3 3( , , )x y z
1 1 1( , , )x y z2 2 2( , , )x y z
4 4 4( , , )x y z
VXY
00
a
a
X Y
Local Excitation Local excitationDelocalized ExcitaionExciton
Local Excitation Local excitationDelocalized ExcitaionExciton
VXY
00
a a
X Y
Degenerate Near-degenerate
state 23aE E V
23 2 30
1( )
2R R
������������������������������������������
23aE E V
23 20 300
1( )
2 a aR R ������������������������������������������
state
2 223
1 1( ) ( ) 42 2b a b aE V
2323 20 302 2
23
( )( ) 4
b aa a
b a
VR R
V
������������������������������������������
2 223
1 1( ) ( ) 42 2b a b aE V
2323 20 302 2
23
( )( ) 4
b aa a
b a
VR R
V
������������������������������������������
23 2320 30 20 3023 3 5
23 23
2 3 2 23 3 23
20 30 323
3( )( )
[ 3( )( )]
a a a a
a a
R RV
R R
e e e e e e
R
������������������������������������������������������������������������������������
23 2320 30 20 3023 3 5
23 23
2 3 2 23 3 23
20 30 323
3( )( )
[ 3( )( )]
a a a a
a a
R RV
R R
e e e e e e
R
������������������������������������������������������������������������������������
1
2
3
4
5
6
α
β
23 0V
α
β23 0V
Rα Rβ V23Rα
V23>0 + - +
V23<0 - + +
Rquirement: Magnetic transition moment is smaller(π-π*)
Strong absorption (ε>1000)
Polarization Direction of Chromophore
Geometry of Molecule
2 3 2 23 3 23 23 2 3[ 3( )( )][ ( )]e e e e e e e e e
SignCDE
α
β
23 0V
23 0V
1Bb(220 nm)1Lb(310 nm)
1La(285 nm)
State Del ta E(eV) WaveL(nm) f1 4.3746 283.42 f=0.06052 4.4532 278.41 f=0.00003 5.4711 226.62 f=0.00004 5.5203 224.6 f=0.00005 5.7449 215.81 f=0.00006 5.7788 214.55 f=0.00007 5.8622 211.5 f=1.26068 6.0958 203.39 f=0.19979 6.1395 201.94 f=0.000010 6.1963 200.09 f=0.0000
Transi tion DipoleState x y z WaveL(nm)
1 -0.7515 0 0 283.427 0 2.9627 0 211.58 -1.1563 0 0 203.39
Polarization Direction of Chromophore
O
O
N
N
N
N
Del taE(eV) WaveL(nm) f TD(AU) x y z4.6926 264.21 0.017 0.2386 -0.0574 -0.34.7055 263.49 0.066 0.0231 0.7573 -0.02284.8725 254.46 f=0.573 2.192 0.0009 0.032
N N 260 nm
200 250 300 350 400 450 500
0.0
0.2
0.4
0.6
0.8
1.0
BPP
Ab
s
Wavelength/nm
(R)-BEBPB
O
O
N
N
N
N
PF64 x
(R)-CBEBPB
O
O
N
N
N
N
PF64 x
O
O
N
N
N
N
O
O
N
N
N
N
(R)-BEBPB1r
(R)-BEBPB2r
O
O
N
N
N
N
O
O
N
N
N
N
(R)-CBEBPB1r
(R)-CBEBPB2r
Conformational Analysis
1 Guess of initial conformation
R-BEBPM
A simple optimazaition
2 Rotation of Dihedral Angles
Name D7-8-21-22 D8-21-22-23 D21-22-23-27 D4-7-11-12124.fchk -105 145 177 -96
1 -110 -171 168 -961a -110 -171 45 -961b -110 -171 -45 -9610 -110 -85 168 -9610a -110 -85 -60 -9611 110 -171 168 -9611a 110 -171 -75 -96110 110 80 168 -96110a 110 80 75 -961100 110 0 168 -96111 -180 -171 168 -96111a -180 -171 80 -96111b -180 -171 -80 -961110 -180 -80 168 -961110a -180 -80 -80 -961111 -180 70 168 -961111a -180 70 60 -96
3 Geometric Optimization of PM3
PM3
NameD7-8-21-
22D8-21-22-23
D21-22-23-27
D4-7-11-12
25-26-28-33
30-31-40-45
Energy(au)
1 -110 -171 168 -98 100 47 1.5288
1a -110 -171 168 -98 100 47 1.5288
1b -100 -87 -158 -93 75 47 1.5257
10 -118 -95 -173 -97 83 47 1.5229
1100 -118 -95 -173 -97 83 47 1.5229
10a -77 -69 -77 -87 82 47 1.5225
11a 113 177 -64 -94 87 47 1.5369
110 -146 76 169 -101 106 47 1.5261
1111 -150 81 162 -102 101 47 1.5234
110a 131 94 68 -100 102 47 1.5296
111 -110 -171 169 -98 100 47 1.5288
111b -111 -172 169 -98 100 47 1.5288
1110 -129 -111 146 -97 111 47 1.528
1111a -152 76 121 -107 71 47 1.5258
1110a -98 -72 -130 -95 70 47 1.5263
111a
11 -77 -69 -77 -87 82 0 1.5218
3 Geometric Optimization of HF/3-21G
HF/3-21G
NameD7-8-21-
22D8-21-22-23
D21-22-23-27
D4-7-11-12
25-26-28-33
30-31-40-45 Energy Dipole
124.fchk -105 145 177 -96 91 60
-2120.94
8 7.4666
1a -105 145 177 -96 91 60
-2120.94
8 7.466
1b -105.51 144.91 176.74 -96.07 1.11 60.29
-2120.94
8 7.4622
10 -105 145 177 -96 91 60
-2120.94
8 7.4663
111 -105 145 177 -96 91 60
-2120.94
8 7.4652
110 -105 145 177 -96 91 60
-2120.94
8 7.3908
1110 -105 145 177 -96 91 60
-2120.94
8 7.4582
1111a -105 145 177 -96 91 60
-2120.94
8 7.4662
10a -58 -74 -74 -81 35 60
-2120.94
4 30.582
11a 124 -173 -68 -110 72 60-
2120.95 6.2576
110a 146 106 71 -105 138 60
-2120.94
5 8.858
1111a 110
101b
4 Geometric Optimization of B3LYP/6-31G*
R-CBEBPB
29-30-33-34 43-44-47-48 8-7-11-16 21-23-24-27 22-25-26-41 Energy-33.48359 -34.21224 -96.16517 -49 63 -2376.2116
Analysis of CD with Exciton Coupling Theory
直角坐标x y z
1 5.32737 3.81657 3.56579
2 5.14853 3.79653 1.13187
3 0.72707 2.4359 0.00426
4 0.70782 0 0
单位向量A x y z
r2 2.44056 e2 0.07328 0.00821 0.99728
r23 4.76152 e23 -0.9286 -0.2858 -0.2368
r3 2.43598 e3 -0.0079 -1 -0.0017
e2e3 -0.0105333
e2e23 -0.3065631
e3e23 0.29349867
(e2×e3) 0.99723068 -0.0078 -0.0732
x y ze2e3-3(e2e23)(e3e23) 0.25939434
e23.(e2×e3) -0.9064558
μb/AU 2.9627 Wavenumber/cm-1
μa/AU 2.9627
rb/angstrom 1.56678242
ra/angstrom 1.56678242
σb/nm 229.0 43668.12227
σa/nm 229.0 43668.12227
CD谱上的/nm
1/2(σa+σb) 229.0 43668.12227
Sign of Cotton Effect -0.2351295
V23/cm-1 685.0397101
ΔE 685.0397101
Eα 232.6 42983.08256
Eβ 225.5 44353.16198
Rα -1321.4136
Rβ 1321.41356
V23R -905220.76
Name λs λ0 λl R/10-40cgs CDλl
1 222 226 233 -1321.41 -4 257.7 260 262 -24.5 -5 220 240 260 76.16 +6 220 240 260 -8.97 -7 260 272 285 -6.93 -8 260 272 285 8 +
E1 222 226 233 649.0 -
E2 249 261 267 -24.3763447 -
E3 267 277 292 117.9 +
Conclusion: 222 and 233: mainly originated from dipole interaction between long polarization axis of naphthalenes 249 and 267: mainly originated from sum of dipole interaction between viologens, and, between viologens
and long polarization axis of naphthalenes. 267 and 292: mainly originated from sum of dipole interaction between viologens and short polarization
axis of naphthalenes. Asymmetric peaks at 222 nm and 233 nm,249 nm and 267 nm: mainly because of summing a positiva
Cotton Effect from 260 nm to 220 nm at the center of 240 nm originated from dipole interaction between
viologens, between viologens and long polarization axis of naphthalenes.
R-CBEBPB
400 500 600 700 800 900 1000 1100
-150
-100
-50
0
ORD Caculated from Experimental Rotational Strength ORD Scaled Experimental Data
[a]
Wavelength / nm
R-BEBPB
400 500 600 700 800 900 1000 1100
0
100
200
300
400
500
600
ORD Calculated from Experimental Rotational Strength ORD Scaled Experimental Data
[a]
Wavelength / nm
ORD Calculated from Experimental Rotational Strength
Plans
1 Synthesis and Characterization of Chiral Polymers Containing Viologen
N N
2 Calculation of the polarization derection
3 Plan to write my paper