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Photophysical Properties of a Rhodium Tetraphenylporphyrin‐tin Corrole Dyad. The First Example of a Through Metal–Metal Bond Energy Transfer †
Author(s) -
Poulin Jason,
Stern Christine,
Guilard Roger,
Harvey Pierre D.
Publication year - 2006
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/2005-06-16-ra-577
Subject(s) - corrole , tetraphenylporphyrin , rhodium , metal , tin , energy transfer , photochemistry , chemistry , materials science , porphyrin , chemical physics , catalysis , organic chemistry
The luminescence spectroscopy study and the determination of the photophysical parameters for the M‐M′‐bonded rhodium meso‐tetraphenylporphyrin‐tin(2,3,7,13,17,18‐hexamethyl‐8,12‐diethylcorrole) complex, (TPP)Rh‐Sn(Me 6 Et 2 Cor) 1, was investigated. The emission bands as well as the lifetimes (τ e ) and the quantum yields (φ e ; at 77 K using 2MeTHF as solvent) were compared with those of (TPP)RhI 2 (TPP = tetraphenylporphyrin) and (Me 6 Et 2 Cor)SnCl 3 (Me 6 Et 2 Cor = 2,3,7,13,17,18‐hexamethyl‐8,12‐diethylcorrole) which are the two chemical precursors of 1. The energy diagram has been established from the absorption, fluorescence and phosphorescence spectra. The Rh(TPP) and Sn(Me 6 Et 2 Cor) chromo‐phores are the energy donor (D) and acceptor (A), respectively. The total absence of fluorescence in 1 (while fluorescence is observed in the tin derivative 3) indicates efficient excited state deactivation, presumably due to heavy atom effect and intramolecular energy transfer (ET). The large decreases in τ p and φ p of the Rh(TPP) chromophore going from 2 to 1 indicate a significant intramolecular ET in the triplet states of 1 with an estimated rate ranging between 10 6 and 10 8 s –1 . Based on the comparison of transfer rates with other related dyads that exhibit similar D‐A separations and no M‐M′ bond, and for which slower through space ET processes (10 2 –10 3 s –1 ) operate, a through M‐M′ bond ET has been unambiguously assigned to 1.