Electronic structure and photophysical properties of quinolinic anhydride, quinolinic thioanhydride, and N-methylquinolinimide

Abstract

The photophysical properties of the title compounds have been investigated by the following methods: He^I photoelectron spectroscopy, u.v. absorption, ¹H and ¹³C n.m.r. spectroscopy. The main features of these spectra (the ordering and splitting of the n CO and π_X ionizations, the location and nature of the n→π and π→π transitions, and the spread of the chemical shifts) have been surveyed and interpreted in terms of qualitative and correlative arguments and also with the aid of ab initio and semiempirical calculations. The electric dipole moments of quinolinic thioanhydride and N-methylquinolinimide have been also measured in benzene solution at 25 °C and compared with those of their benzene congeners.