Infrared and Raman spectroscopy of 9-acridinones

IR and Raman spectra of 9-acridinone and its five derivatives were measured in condensed phases in order to demonstrate the influence of the constitut ion of the compounds on the appearance of vibrational bands. Experimental s pectra were compared with theoretically predicted transitions, also for fou r other 9-acridinones (on the density functional theory level using the B 3 LYP functional and 6-31G** basis set), which enabled selected vibrational m odes to be ascribed to bands in the spectra. Substitution influences the va lues of the wave-numbers of characteristic stretching and bending modes, i. e. those corresponding to the keto group and fragments of molecules contain ing the heterocyclic nitrogen atom. Moreover, some vibrational transitions, e.g, those corresponding to C=O stretching modes, were found to be correla ted with structural and physicochemical features of the compounds, such as bond length, atomic partial charges on selected atoms, and dipole moments. (C) 2001 Elsevier Science B.V. All rights reserved.