Orbital vibronic interaction analysis of the electronic spectra of cycl[3.2.2]azines

Abstract

A Cycl[3.2.2]azine molecule ([2.2.3]cyclazine) has a rigid C2v plane structure with a sp2-hybridized carbon perimeter clipped by a central nitrogen atom, as an isoelectronic analogue of a [10]-annulene. Various types of cyclazines have been reported and attracted much attention from physicochemical, magnetic, biological as well as graph-theoretical viewpoints. Despite their interesting properties, no systematic quantum chemical analysis have been reported to characterize the UV/Vis intense electronic peaks and the associated sidebands. In this study, semi-quantitative (TDDFT) and quantitative (MS-CASPT2) analysis are presented for a cycl[3.2.2]azine, its benzo-annulated and the maleimide-linked derivatives. Furthermore, the detailed spectral structures were analyzed on the basis of the orbital vibronic coupling interaction scheme.