Preparation of imido pentamethylcyclopentadienyl molybdenum(IV) complexes. X-ray molecular structure of cis-[MoCp*CI(η-NtBu)]2·C6H6

Abstract

The reduction of [MoCp * Cl2(NtBu)] 1 with 1 equiv. of 10% sodium amalgam in the presence of CN(2,6-Me2C6H3) yields the green crystalline compound [MoCp * Cl(NtBuCN(2,6-Me2C6H3)] 2 which can be alkylated by MgClMe to give [MoCp * Me(NtBu)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)(NtBu)]24 which are slowly and irreversibly transformed into cis-[MoCp * Cl(μ-NtBu)]25 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-NtBu)]26, and react with ethylene to yield the adduct [MoCp * Cl(NtBu)(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-NtBu)]25 was determined by X-ray diffraction methods.