Nature of the lowest electron transitions in the linear conjugated systems derivatives of 2,6-diphenylthiapyrylium: Cationic trimethinecyanine, neutral ethylene, its dication and cation-radical
作者:M.O. Kudinova、D.O. Melnyk、O.D. Kachkovsky、O.I. Tolmachev
DOI:10.1016/j.molstruc.2011.06.036
日期:2012.3
A series of linear conjugated systems of different types containing the 2,6-diphenylthiapyrylium residues as terminal groups have been synthesized and investigated by the combined spectral and quantum-chemical methods. The analysis of calculated by ab initio and semi-empirical methods of their molecular geometry and electron structure, and nature of the lowest electron transitions has shown that four types, cationic cyanine, neutral polyene, polyene-dication and cationic polyene-radical differ fundamentally each other by the charge distribution and alternation of bond lengths along pi-electron system, as well as by nature of their lowest electron transitions and hence of shapes of the absorption bands. It was established the cyanine-like similarity of the "middle" high intensive and narrow spectral band for the cationic polyene-radical and cyanine dye, whereas the polyene with the close electron shell exhibit the comparatively wide longwavelength bands. (C) 2011 Elsevier B.V. All rights reserved.