Synthesis, characterization, and reactivity of sulfided hexanuclear molybdenum cluster compounds

摘要

Hexanuclear molybdenum clusters with mixed chloride and sulfide bridging ligands were prepared by reacting (alpha)-MoCl(sub 2) with sodium hydrosulfide in the presence of sodium butoxide. The resulting species, Mo(sub 6)Cl(sub (8-x))S(sub x)(center dot)npy(x (congruent) 3.6, n (congruent) 4, py = pyridine), was pyrophoric and insoluble. The mixed sulfide chloride cluster species Mo(sub 6)S(sub 4)Cl(sub 4)(center dot)6OPEt(sub 3) and Mo(sub 6)S(sub (approximately)5)Cl(sub (approximately)3)(center dot)6PEt(sub 3) and Mo(sub 6)S(sub 8)(center dot)6PEt(sub 3) were isolated and characterized. Phosphorus-31 nuclear magnetic resonance, electron paramagnetic resonance, and UV/visible spectra were obtained for each fraction. The completely sulfided cluster, Mo(sub 6)S(sub 8)(center dot)6PEt(sub 3), was prepared similarly and used in various experiments as a possible precursor to Chevrel phase materials of the type Mo(sub 6)S(sub 8)or M(sub n)Mo(sub 6)S(sub 8). With the goal of removing all of the triethylphosphine ligands, Mo(sub 6)S(sub 8)(center dot)6PEt(sub 3) was reacted with the transition metal carbonyls molybdenum hexacarbonyl and dicobalt octacarbonyl. Reaction on the molecular sulfide cluster with copper(I) chloride in toluene gave a completely insoluble product. The reaction of Mo(sub 6)S(sub 8)(center dot)6PEt(sub 3) with propylene sulfide gave a product whose infrared spectra showed only very weak peaks associated with coordinated triethylphosphine. The elemental analysis of this product fit the formula Mo(sub 6)S(sub 8)(center dot)5SPEt(sub 3). Reactivity of the outer ligands of the Mo(sub 6)S(sub 8)(center dot)npy and Mo(sub 6)S(sub 8)(center dot)(6(minus)x)PrNH(sub x) clusters were investigated. Crystalline Mo(sub 6)S(sub 8)(center dot)6THT was recovered from the reaction of the n-propylamine derivative with THT. A crystal structure determination was done. 87 refs., 12 fig., 15 tabs.