Preparation of imido pentamethylcyclopentadienyl molybdenum(IV) complexes: X-ray molecular structure of cis-[MoCp * Cl(μ-NtBu)]2C6H6

Article abstract of DOI:10.1016/S0022-328X(96)06855-6

The reduction of [MoCp * Cl₂(N^tBu)] 1 with 1 equiv. of 10% sodium amalgam in the presence of CN(2,6-Me₂C₆H₃) yields the green crystalline compound [MoCp * Cl(N^tBu{CN(2,6-Me₂C₆H₃)}] 2 which can be alkylated by MgClMe to give [MoCp * Me(N^tBu){CN(2,6- Me₂C₆H₃)}] 3. The same reduction in the absence of ligands leads to an almost equimolar mixture of compounds identified as cis- and trans-[MoCp * (μ-Cl)(N^tBu)]₂ 4 which are slowly and irreversibly transformed into cis-[MoCp * Cl(μ-N^tBu)]₂ 5 by heating a toluene solution at 90°C. Compounds (cis + trans)-4 and cis-5 are alkylated by MgClMe leading to the same final methyl derivative [MoCp * Me(μ-N^tBu)]₂ 6, and react with ethylene to yield the adduct [MoCp * Cl(N^tBu)(C₂H₄)] 7. All new complexes were characterized by their analytical composition, IR and NMR spectroscopy and mass spectrometry, and the structure of the benzene solvate of cis-[MoCp * Cl(μ-N^tBu)]₂ 5 was determined by X-ray diffraction methods.