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Indexed by:期刊论文

Date of Publication:2011-10-15

Journal:SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

Included Journals:Scopus、SCIE、EI

Volume:81

Issue:1

Page Number:283-289

ISSN No.:1386-1425

Key Words:Hydrogen bonding; Fluorescence quenching; Excited state; Aminostyryl terpyridine; Twisted intramolecular charge transfer

Abstract:The synthesis, structure and photophysical behavior of the aminostyryl terpyridine derivatives, named 4'-(4-{2-[4-(N,N-dimethylaniline)]vinyl}phenyl)-2,2':6',2 ''-terpyridine (M-1) and the related model compounds 4'-(4-{2-[4-(N,N-diphenylammino)phenyl]vinyl}phenyl)-2,2':6'.2 ''-terpyridine (M-2), respectively, are reported. Large solvatochromic shifts of the first excited-state fluorescence maximum suggest the intramolecular charge transfer characters for both compounds. In addition, with N,N-dimethyl substituents, its fluorescence is quenched a lot in protic solvents. This is consisted with the decay of its S-1 state, through nonradiative internal conversion, to the ground state, which is facilitated by the formation of the hydrogen bond between M-1 and alcohols. Whereas, the introduction of N,N-diphenyl substituents has been proved to be a hydrogen-bond-free case with the unchanged Phi(f). Furthermore, the formation of TICT state via diffusive twisting motion of the dimethyl/phenylamino group is the major relaxation process, which is proved by the ultrafast relaxation dynamics experiment and theoretically conformational optimization of the first excited-state of both the compounds. (C) 2011 Elsevier B.V. All rights reserved.