Excited-state dynamics of normal and doubly N-confused type hexaphyrin derivatives studied by time-resolved fluorescence measurements

Autor:	Hiroyuki Furuta, Kiyohisa Nakamura, Fuyuki Ito, Shigeru Itoh, Toshihiko Nagamura, Jang Hyun Ryu, Yutaka Shibata
Rok vydání:	2007
Předmět:	Chemistry Time constant General Physics and Astronomy Photochemistry Porphyrin Molecular physics Fluorescence chemistry.chemical_compound Excited state Ultrafast laser spectroscopy Physical and Theoretical Chemistry Time-resolved spectroscopy Ground state Conformational isomerism
Zdroj:	Chemical Physics Letters. 443:274-279
ISSN:	0009-2614
DOI:	10.1016/j.cplett.2007.06.097
Popis:	The excited-state dynamics of two expanded porphyrin derivatives which have six pyrrole rings of normal and doubly N-confused types was studied by time-resolved fluorescence and transient absorption measurements. We have found that their dynamics is very different due to four substituents in the doubly N-confused hexaphyrin derivative. The bleaching recovery of the free-base doubly N-confused hexaphyrin shows the double exponential function with time constants of τ = 80 ± 10 ps and 47 ± 10 ps. The fluorescence decay curve, on the other hand, shows single-exponential function. To explain such behavior, we propose a model that the recovery process originates from two conformers in the S 1 state. It is plausible that the two excited-state conformers are deactivated independently to the ground state with radiative and nonradiative processes, respectively.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::2cf216b610ae5a8ab2a569f7cfb579d8 https://doi.org/10.1016/j.cplett.2007.06.097 Zobrazit plný text záznamu Full Text from ScienceDirect