147281-45-6Relevant academic research and scientific papers
Cyclopentadienone Complexes of Molybdenum: Synthesis of Carbonyl, Acetonitrile, Phosphine and Phosphido-bridged Derivatives
Adams, Harry,Bailey, Neil A.,Hempstead, Paul D.,Morris, Michael J.,Riley, Sarah,et al.
, p. 91 - 100 (2007/10/02)
Reaction of with 2 equivalents of tetraphenylcyclopentadienone (tetracyclone) in refluxing toluene gives 4-C4Ph4CO)2> 1a in ca. 95percent yield.With 1 equivalent of tetracyclone in boiling heptane, 4-C4Ph4CO)>2> 2 is produced as well as 1a.This dimeric complex has been crystallographically characterised (no. 2), a = 8.980(3), b = 11.332(4), c = 13.526(5) Angstroem; α = 77.55(3), β = 71.94(3), γ = 81.02(3) deg, Z = 2 monomer units>; each molybdenum is in a distorted-octahedral environment, co-ordinated by the η4-diene ligand, three carbonyl ligands, and the ketonic carbonyl of the other centrosymmetrically related tetracyclone.Another convenient route into the chemistry of tetracyclone molybdenum complexes is provided by 4-C4Ph4CO)> 5 which is formd in high yield by treating with tetracyclone.One (but only one) of the tetracyclone ligands of complex 1a can be displaced by chelating phosphines to give 4-C4Ph4CO)> (L-L = Ph2PCH2PPh2 or Ph2PCH2CH2PPh2); the stereochemistry and fluxionality of these complexes is briefly discussed.Thermal reaction of 1a with monodentate phosphines (L = PPh3 or PPh2Me) yields 4-C4Ph4CO)> 7 by a carbonyl redistribution process; the same compounds can be prepared from 5 by displacement of the labile acetonitrile ligand, as can an analogous species with L = PPh2H.Thermolysis of 4-C4Ph4CO)> or thermal reaction of 1a with PPh2H gives the phosphido-bridged complex 5-C4Ph4CO)(η5-C4Ph4COH)> 8.The crystal structure of 8 has also been determined (C1i, no. 2), a = 12.806(10), b = 14.173(8), c = 17.958(7) Angstroem, α = 83.75(4), β = 86.92(5), γ = 71.57(5) deg, Z = 2> and reveals a formal Mo=Mo double bond bridged by a diphenylphosphido group and a tetracyclone ligand bonded in a ?-η5 manner.The other tetracyclone is bonded as an η5-hydroxytetraphenylcyclopentadienyl ligand, having taken up the proton released by oxidative addition of the P-H bond.
