Spectroscopic Investigations of Merocyanines-1. UV- and NMR-Spectra of Malodintrile-Substituted Vinylogen Acid Amides.

Article abstract of DOI:10.1002/bbpc.19760800711

UV and NMR spectra of open chained merocyanine dyes are investigated and model calculations are performed within the Pariser Parr Pople approximation. The introduction of charged pseudo centers permits the calculation of the solvent dependent shifts in the electronic absorption spectra. A good correlation is also found between computed pi -charge densities and observed **1H chemical shifts. Due to the high electronegativity of the malonitrile group, the electronic structure and spectroscopic behavior of the investigated compounds approach that of the symmetrical polymethine dyes.