Circular dichroism calculations

Huige and Hezemans179 180 have performed extensive molecular mechanics calculations using the consistent force-field method on various oligo- and polyisocyanides. The hexadecamer of ferf-butyl isocyanide was calculated to have a helical middle section and disordered ends. The dihedral angle N=C—C=N in the middle section was found to be 78.6°, and the number of repeat units per helical turn was 3.75. The latter number is in agreement with circular dichroism calculations using Tinoco s exciton theory (3.6—4.6) and De Voe s polarizability theory (3.81). The molecular mechanics calculations further predicted that the less bulky polymers 56 and 57 form helical polymers as well, whereas a disordered structure was calculated for poly(methyl isocyanide) (55). 

Bak KL, Jtirgensen P, Helgaker T, Ruud K (1994) Basis set convergence and correlation effects in vibrational circular dichroism calculations using London atomic orbitals. Faraday Discuss 99 121-129... 

Hirst, J.D. Improving protein circular dichroism calculations in the far-ultraviolet through reparametrizing the amide chromophore. J. Chem. Phys. 109, 782-788 (1998)... 

The circular dichroism curves for a variety of penicillanic acid derivatives have been published and discussed (B-77MI51100) and have been used to support extended Hiickel MO calculations (77T711). 

Fig. 6.—Measured Circular Dichroism Spectrum (-----), Calculated Circular Dichroism...

Fig. 7.—Predicted (- -) and Fragment (—) Circular Dichroism Spectra /3-L-Arabinose Calculated from (a) a-D-Xylose, and (b) Methyl /3-L-Aiabinoside a-L-Arabinose Calculated from (c) j3-D-Xylose, and (d) Average Calculated for /3-L-Arabinose Methyl a-L-Arabinoside Calculated from (e) Methyl /3-D-Xyloside, and (f) Methyl /3-L-Arabinoside. (Redrawn from Ref. 6.)...

Stephens, P. J., Devlin, J. F., Chabalowski, C. F., Frisch, M. J, 1994, Ab Initio Calculations of Vibrational Absorption and Circular Dichroism Spectra Using SCF, MP2, and Density Functional Theory Force Fields , J. Phys. 

The redox potentials of zinc-substituted phthalocyanines are shown to be linearly dependent on the total Hammett substituent constant.837 In 1987, Stillman and co-workers used the absorption and magnetic circular dichroism spectra of the zinc phthalocyanine and its 7r-cation-radical species to assign the observed bands on the basis of theoretical calculations. The neutral and oxidized zinc phthalocyanine complexes with cyanide, imidazole, and pyridine were used with the key factor in these studies the stability of the 7r-cation-radical species.838 The structure of zinc chloro(phthalocyaninato) has been determined and conductivity investigated.839... 

Danya Yang and Arvi Rauk, The A Priori Calculation of Vibrational Circular Dichroism Intensities. 

We shall not cover such other methods as theoretical calculations of the sign of optical rotation, circular dichroism, and so on in solution these have been recently reviewed in an excellent book by Mason (12). 

Determination of the absolute configurations of these optically active fullerene derivatives was possible by comparison of their experimental and calculated circular dichroism (CD) spectra [96]. Tether controlled bis-cyclopropanation reactions have been extensively used to synthesize extended fimctional architectures such as dyads. 

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