Photophysical and photochemical studies of tricarbonyl rhenium(i) N-heterocyclic carbene complexes containing azide and triazolate ligands. (26th February 2016)

• Record Type: Journal Article
• Authors: Simpson, Peter V.; Skelton, Brian W.; Raiteri, Paolo; Massi, Massimiliano
• Is Part Of: New journal of chemistry. Volume 40:Number 7(2016:Jul.)
• Page Start: 5797
• Page End: 5807
• Publication Date: 2016-02-26
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c5nj03301b
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Rhenium NHC complexes bound to azide anions readily react with alkynes to form the corresponding triazolate complexes, a new class of photochemically active species. Abstract : Rhenium(i ) N-heterocyclic carbene (NHC) complexes of the type fac -[Re(CO)3 (NHC)L ] with either azide or triazolate ancillary ligandsL and pyridyl or pyrimidyl substituted imidazolyl units have been prepared and structurally characterised, and their photophysical and photochemical properties studied. All of the complexes exhibit phosphorescent emission from triplet metal-to-ligand ( 3 MCLT) excited states, typical of tricarbonyl Re(i ) complexes, with the triazolate bound complexes having higher quantum yields and longer decay lifetimes compared to the azide bound complexes. The complexes containing pyridyl substituted imidazolyl units are photoreactive when dissolved in acetonitrile and undergo photochemical CO dissociation, the rate of which is significantly greater in the azide cf. triazolate complex. The photochemical mechanism of the azide/pyridyl complex was analysed and appears to give the same products, albeit with different ratios, to previously reported complexes whereL is a halide. A reaction mechanism is proposed.