Intramolecular charge transfer processes in a series of styryl derivatives of pyridine and quinoline N-oxides

Intramolecular charge transfer processes in a series of thetrans-isomers of styryl derivatives of pyridines and quinolines, their hydrochlorides and molecular complexes with BF₃ have been studied by electronic and IR spectroscopy. Electron donor groups involved in direct resonance conjugation with the N-oxide group intensify these processes, while electron acceptor nitro groups somewhat weaken them. Protons and BF₃ coordinate to the oxygen of the NO group to form strong 11 complexes, except in the cases of 4-(4-dimethylaminostyryl)quinoline and pyridine N-oxides, in which a second acceptor molecule adds to the amino group.Petrozavodsk State University, Petrozavodsk 185640, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, 1093–1102, August, 1998.