Electron structure and nature of electron transitions of squaraine and thiosquaraine as well as their 1,2-isomers

[Display omitted] •We study squaraine and thiosquaraine with 2,6-di-t-Bu-substituted pyrylium residues and their 1,2-isomers.•Both isomers exhibit similar electronic structures in ground state.•UV–Vis absorption spectra of isomers differ due to the conjugated system. This paper presents the results...

Full description

Saved in:

Bibliographic Details
Published in:	Journal of molecular structure Vol. 1076; pp. 583 - 591
Main Authors:	Kurdyukov, V.V., Tolmachev, O.I., Kachkovsky, O.D., Pavlenko, E.L., Dmytrenko, O.P., Kulish, N.P., Iakovyshen, R.S., Brusentsov, V.A., Seryk, M., Momot, A.I.
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 05-11-2014
Subjects:	NMR spectroscopy Quantum-chemical calculations Squaraines UV–Vis absorption UV–Vis absorption NMR spectroscopy Squaraines Quantum-chemical calculations
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	[Display omitted] •We study squaraine and thiosquaraine with 2,6-di-t-Bu-substituted pyrylium residues and their 1,2-isomers.•Both isomers exhibit similar electronic structures in ground state.•UV–Vis absorption spectra of isomers differ due to the conjugated system. This paper presents the results of spectral measurements of UV–Vis absorption and 13C NMR spectra as well as quantum-chemical studies of molecular geometry and electron structure of squaraine, thiosquaraine and their corresponding 1,2-isomers. In the ground state 1,3- and 1,2-isomers have similar charge distributions and bond lengths within their chromophores but differ substantially in energy gap sizes and spectral properties, most prominently the maxima positions and intensities of long wavelength absorption bands. The replacement of oxygen atoms connected to the central cycle in squaraine with less electronegative sulfur atoms evokes a relatively intensive band in the short wavelength spectral region.
ISSN:	0022-2860 1872-8014
DOI:	10.1016/j.molstruc.2014.07.076