Syntheses, spectral and structural characterization of η5- and η6-cyclic π-perimeter hydrocarbon platinum group metal complexes containing pyridazine-NHC analogues

A family of platinum group metal complexes containing bidentate pyridazine-NHC ligands (L1 = 3,6-bis(N-n-methylimidazolyl)pyridazine dichloride, L2= 3,6-bis(N-n-butylimidazolyl)pyridazine dichloride) have been synthesized. The typical mechanism of the reactions for these syntheses involved an in situ carbene transfer reactions. Reaction of L1/L2 with silver oxide in absence of light yielded silver-NHC complexes (1) and (2). When, the respective metal precursors were added to the silver-NHC complexes, transmetallation occurred with the possible isolation of the following cationic complexes: [(eta(6)-C6H6)Ru(L)Cl](2+) (L = L1 (3), L2 (5)}. [(eta(6)-P-(PrC6H4Me)-Pr-i)Ru(L)Cl](2+) {L = Li (4), L2 (6)}, [Cp*Rh(L)Cl](2+) {L = L1 (7), L2 (9)) and [Cp*Ir(L)Cl](2+) {L = L1 (8), L2 (10)]. All these complexes were stable in ambient atmosphere, and could be obtained in good yield. All these complexes were characterized by spectroscopic analyses. The molecular structure of the complex 9 was determined by single crystal X-ray diffraction studies. (C) 2011 Elsevier Ltd. All rights reserved.