Picosecond time-resolved infrared spectroscopic investigation into electron localisation in the excited states of Re(I) polypyridyl complexes with bridging ligands

Marina K. Kuimova, Keith C. Gordon, Sarah L. Howell, Pavel Matousek, Anthony W. Parker, Xue Zhong Sun, Michael Towrie, Michael W. George

Research output: Journal PublicationArticlepeer-review

10 Citations (Scopus)

Abstract

Mono- and binuclear complexes of (Re(CO)3Cl) with dipyrido[2,3-a:3′,2′-c]-6,7-dimethylphenazine (ppbMe2) were synthesised and their photophysical properties probed using picosecond time-resolved infrared spectroscopy (TRIR). Excitation of these complexes in solution at 400 nm produces short-lived excited states. The IR spectrum of the excited state of the mononuclear [Re(CO)3Cl(ppbMe2)] have ν(CO) bands shifted to higher wavenumber relative to those of the ground state. This is consistent with formation of a 3MLCT excited state. The IR spectrum of the excited state of the bimetallic [(Re(CO)3Cl)2(μ-ppbMe2)] shows the formation of two distinct groups of ν(CO) bands. This is interpreted as the formation of two distinct Re sites arising from a localised MLCT state with formally oxidised Re centre and a formally reduced bridging ligand. The ν(CO) bands of the adjacent Re centre are affected by the reduction of the bridging ligand. On the IR timescale the excited state structure is best formulated as [Cl(CO)3ReII(μ-ppbMe2˙-)ReI(CO)3Cl].

Original languageEnglish
Pages (from-to)82-87
Number of pages6
JournalPhotochemical and Photobiological Sciences
Volume5
Issue number1
DOIs
Publication statusPublished - 4 Jan 2006
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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