QUANTUM-CHEMICAL STUDY OF THE RELATION BETWEEN ELECTRONIC-STRUCTURE AND IR-SPECTRA OF NEUTRAL MOLECULES, ANION-RADICALS, AND DIANIONS OF AROMATIC NITRILES

The relation between the IR data and the calculated by the CNDO/2 line ar relationship method has been studied. The between the experimentall y measured v(C=N) and the corresponding Wiberg bond Index (W-C=N) has been found for the series of conjugated nitriles including neutral mol ecules. anion - radicals and dianions. The changes in ti-ie intensity of the stretching C=N vibration on transition from a neutral molecule into anion - radical and dianion have been investigated by the CNDO/2 method. The calculated values for partial derivative mu/partial deriva tive O-CN show that in tile order: neutral molecule, anion - radical a nd dianion the IR intensity of the stretching C=N vibration significan tly increases.