title: Heteroleptic rhodium NHC complexes with pyridine-derived ligands: synthetic accessibility and reactivity towards oxygen.
abstract: The synthesis, structure determination and oxidative stability of novel Rh-NHC complexes which feature pyridine-derived ligands have been described. All complexes described herein were synthesized from common dinuclear precursors of general structure [Rh(NHC)(L)Cl](2), where L is a monodentate olefin. We demonstrate that the use of these precursors is critical for the formation of all complexes since related cyclooctadiene containing precursors ([Rh(NHC)(COD)Cl]) were completely unreactive under identical conditions. We further demonstrate that complexes with the general formula [Rh(NHC)(olefin)(Py)Cl] or ([Rh(NHC)(BiPy/Phen)Cl]) are extremely sensitive to oxygen, reacting initially to give an adduct with dioxygen, and then decomposing further. The series of compounds and their oxidation products gave a remarkable range of colours which may be useful in the preparation of colourometric oxygen sensors.
authors.affiliation: Department of Chemistry, Queen's University, Chernoff Hall, 90 Bader Lane, Kingston, Canada K7L 3N6.
authors.forename: Olena V
authors.initials: OV
authors.lastname: Zenkina
authors.forename: Eric C
authors.initials: EC
authors.lastname: Keske
authors.forename: Gurpaul S
authors.initials: GS
authors.lastname: Kochhar
authors.forename: Ruiyao
authors.initials: R
authors.lastname: Wang
authors.forename: Cathleen M
authors.initials: CM
authors.lastname: Crudden