title: The use of organolithium reagents for the synthesis of 4-aryl-2-phenylpyridines and their corresponding iridium(iii) complexes.
abstract: A versatile palladium-free route for the synthesis of 4-aryl-substituted phenylpyridines (ppy), starting from tert-butyl 4-oxopiperidine-1-carboxylate, is reported. Reaction with an aryllithium, followed by trifluoroacetic acid dehydration/deprotection and oxidation with 2-iodoylbenzoic acid and finally phenylation, gave 4 ligands (L(1-4)H): 2,4-diphenylpyridine, 4-(4-methoxyphenyl)-2-phenylpyridine, 2-phenyl-4-(o-tolyl)pyridine and 4-mesityl-2-phenylpyridine. These ligands were coordinated to iridium to give the corresponding Ir(L)2(A) complexes (Ir1-7), where A = ancillary ligand acetylacetate or 2-picolinate. This was used to demonstrate that, through a combination of ancillary ligand choice and torsional twisting between the 4-aryl substituents of the ppy ligands, it is possible to tune the phosphorescent emission of the complexes in the range 502-560 nm.
authors.affiliation: Department of Chemistry, Durham University, South Rd, Durham, DH1 3LE, UK. andrew.beeby@durham.ac.uk.
authors.forename: Ross
authors.initials: R
authors.lastname: Davidson
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Hsu
authors.forename: Thomas
authors.initials: T
authors.lastname: Batchelor
authors.forename: Dmitry
authors.initials: D
authors.lastname: Yufit
authors.forename: Andrew
authors.initials: A
authors.lastname: Beeby