title: Strongly phosphorescent neutral rhenium(i) isocyanoborato complexes: synthesis, characterization, and photophysical, electrochemical, and computational studies.
abstract: A new series of neutral isocyanoborato rhenium(I) diimine complexes [Re(CO)3 (N^N)(CNBR3 )], where N^N=bpy, 4,4'-Me2 bpy, phen, 4,7-Me2 phen, 2,9-Me2 phen, 3,4,7,8-Me4 phen; R=C6 F5 , C6 H5 , Cl, 4-ClC6 H4 , 3,5-(CF3 )2 C6 H3 , with various isocyanoborate and diimine ligands of diverse electronic and steric nature have been synthesized and characterized. The X-ray crystal structures of six complexes have also been determined. These complexes displayed intense bluish green to yellow phosphorescence at room temperature in dichloromethane solution. The photophysical and electrochemical properties of these complexes had been investigated. To elucidate the electronic structures and transitions of these complexes, DFT and TD-DFT calculations have been performed, which revealed that the lowest-energy electronic transition associated with these complexes originates from a mixture of MLCT [dπ(Re)→π*(N^N)] and LLCT [π(CNBR3 )→π*(N^N)] transitions.
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (P.R. China), Fax: (+852) 3442-0522.
authors.forename: Wing-Kin
authors.initials: WK
authors.lastname: Chu
authors.forename: Xi-Guang
authors.initials: XG
authors.lastname: Wei
authors.forename: Shek-Man
authors.initials: SM
authors.lastname: Yiu
authors.forename: Chi-Chiu
authors.initials: CC
authors.lastname: Ko
authors.forename: Kai-Chung
authors.initials: KC
authors.lastname: Lau
keywords: charge transfer; emissive materials; isocyanoborate; phosphorescence; rhenium