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( ) �������������� ( )

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( ) ��������������

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

����������������������������

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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

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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

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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