title: Cyclometalated cinchophen ligands on iridium(III): towards water-soluble complexes with visible luminescence.
abstract: Eight cationic heteroleptic iridium(III) complexes, [Ir(epqc)2(N^N)](+), were prepared in high yield from a cyclometalated iridium bridged-chloride dimer bearing two ethyl-2-phenylquinoline-4-carboxylate (epqc) ligands. Two X-ray crystallographic studies were undertaken on selected complexes (where the ancillary ligand N^N = 4,4'-dimethyl-2,2'-bipyridine and 4,7-diphenyl-1,10-phenanthroline) each confirming the proposed formulations, showing an octahedral coordination at Ir(III). In general, the complexes are luminescent (620-630 nm) with moderately long lifetimes indicative of phosphorescence. Hydrolysis of the ethyl ester moieties of the epqc ligands gave the analogous cinchophen-based complexes, which were water-soluble and visibly luminescent (568-631 nm). The spectroscopic and redox characterisation of the complexes was complemented by DFT and TD-DFT calculations, supporting the assignment of dominant (3)MLCT to the emissive character.
authors.affiliation: School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, UK.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Smith
authors.forename: Emily C
authors.initials: EC
authors.lastname: Stokes
authors.forename: Emily E
authors.initials: EE
authors.lastname: Langdon-Jones
authors.forename: James A
authors.initials: JA
authors.lastname: Platts
authors.forename: Benson M
authors.initials: BM
authors.lastname: Kariuki
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hallett
authors.forename: Simon J A
authors.initials: SJ
authors.lastname: Pope