A class of fluorescent heterocyclic dyes revisited: Photophysics, structure, and solvent effects
2009 (English)In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, Vol. 73, no 4, 757-763 p.Article in journal (Refereed) Published
The photophysical behavior of a series of 2-methylthio-5-(Z-carbonyl)thieno-[3,4-e]-3,4-dihydro-1,2,3-triazine-4-o nes was investigated by absorption and emission spectroscopy in a range of solvents representing a systematic variation in polarity, polarizability, as well as hydrogen bond donating and accepting capabilities. In all the investigated compounds, the heterocyclic 6-membered ring of the chromophore is involved in interactions between electron donor and acceptor substituents on the thiophene ring. Throughout the series, the charge-donating methylthio group is kept constant, while the acceptor (Z-carbonyl) is varied between amide, ester, and ketone functionalities. The fluorescent first electronically excited state is primarily of intramolecular HOMO-LUMO charge transfer character. All members of the series exhibit solvent-dependent photophysics, although the magnitude of the dependence varies with the nature of the acceptor group. In addition to the solvent-sensitive photophysics, the investigated class of compounds shows high thermal and chemical stability. Among this class of heterocyclic dyes, the amide-substituted compound is superior with respect to high quantum yield and lifetime, and also shows the largest change in emission lifetimes and fluorescence quantum yields upon solvent variation (about 5-fold). (C) 2009 Elsevier B.V. All rights reserved.
Place, publisher, year, edition, pages
2009. Vol. 73, no 4, 757-763 p.
Fluorescence, Solvatochromism, Charge transfer, Solvent interaction, Hydrogen bond
IdentifiersURN: urn:nbn:se:uu:diva-128388DOI: 10.1016/j.saa.2009.03.026ISI: 000267733800027OAI: oai:DiVA.org:uu-128388DiVA: diva2:331514