Seemingly simple group 8 cyclopentadienyl dicarbonyl metal halides: From little things, interesting things grow†
Abstract
Single crystal X-ray studies are presented for the ‘piano-stool’ structures [CpRu,Os(CO)2Cl], [Cp′Ru(CO)2X] (X = Cl, Br, I (redetermination)), [Cp*Ru(CO)2Cl] (two phases), enabling the assembly of comparative geometric data for the [CpM(CO)2Cl] (M = Fe, Ru, Os), [Cp,Cp′Ru(CO)2X] (X = Cl, Br, I) and [CpxRu(CO)2Cl] (Cpx = Cp (η–C5H5), Cp′ (η–C5H4CH3), Cp* (η–C5CH3)5,CpPh (η–C5(C6H5)5)). In the [Cp′Ru(CO)2X] arrays, the methyl groups are found to consistently lie ‘eclipsed’ vis-a-vis the halogen substituents, with a concomitant tilt of the Cp ring; the reasons for this are explored theoretically.