Origin of the N-methyl and N-phenyl substituent effects on the fluorescence vibronic structures of trans-4-aminostilbene and its derivatives in hexane

Jye Shane Yang, Chin Min Wang, Chung Yu Hwang, Kang Ling Liau, Shih Yi Chiou

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The origin of the N-substituent effect on the room temperature fluorescence vibronic structures of trans-4-aminostilbene (1), its disubstituted derivatives (2 and 3), and the fused-ring analogs (4) in hexane has been investigated. The fluorescence spectra of aminostilbenes 1-4 in hexane are structured and the intensity ratio of the 0,1 vs. the 0,0 band decreases upon N-methyl or N-phenyl substitution, indicating that the N-substituents reduce the displacement in the equilibrium configuration (ΔQe) between the ground and the excited states. Our data are consistent with a planar fluorescing state for 1-4 in hexane. The N-substituents affect the planarity of the ground state structures as well as the conjugation length allowed for exciton resonance, both of which are in accord with the observed progression in fluorescence vibronic structures. According to our analysis, the conformation effect that is associated with the geometry of the amino group appears to play a major role. The corresponding studies on the solvent effect suggest that the fluorescing state of 1-4 in more polar solvents is also a planar charge-transfer state.

Original languageEnglish
Pages (from-to)1225-1231
Number of pages7
JournalPhotochemical and Photobiological Sciences
Volume2
Issue number11
DOIs
StatePublished - Nov 2003

Fingerprint

Dive into the research topics of 'Origin of the N-methyl and N-phenyl substituent effects on the fluorescence vibronic structures of trans-4-aminostilbene and its derivatives in hexane'. Together they form a unique fingerprint.

Cite this