Preparation of imido pentamethylcyclopentadienyl molybdenum(IV) complexes X-ray molecular structure of cis-[MoCp* Cl(mu-(NBu)-Bu-t)](2)center dot C6H6

The reduction of [MoCp*Cl-2((NBu)-Bu-t)] 1 with 1 equiv. of 10% sodium amalgram in the presence of CN(2,6-Me2C6H3) yields the green crystalline compound [MoCp*Cl((NBu)-Bu-t{CN(2,6-Me2C6H3)}] 2 which can be alkylated by MgClMe to give [MoCp*Me((NBu)-Bu-t){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*(mu-Cl)((NBu)-Bu-t)](2) 4 which are slowly and irreversibly transformed into cis-[MoCp*Cl(mu-(NBu)-Bu-t)](2) 5 by heating a toluene solution at 90 degrees C. Compounds (cis + trans)-4 and cis-5 are alkylated by MgClMe leading to the same final methyl derivative [MoCp*Me(mu-(NBu)-Bu-t)](2) 6, and react with ethylene to yield the adduct [MoCp*Cl((NBu)-Bu-t)(C2C4)]. 7. All new complexes were characterized by their analytical composition, IR and NMR spectroscopy, and the structure of the benzene solvate of cis-[MoCp*Cl(mu-(NBu)-Bu-t)](2) 5 was determined by X-ray diffraction methods.