Syntheses, structures, and reactivity of a series of (Pentamethylcyclopentadienyl)molybdenum(V) and -tungsten(V) imido complexes

Reactions of the (pentamethylcyclopentadienyl)molybdenum(V) and -tungsten(V) tetrachlorides ({eta}{sup 5}C{sub 5}Me{sub 5})MCl{sub 4}(M=Mo, W) with the primary amines RNH{sub 2}(R=t-Bu, i-Pr, C{sub 6}F{sub 5}, and 2,6-(i-Pr){sub 2}C{sub 6}H{sub 3}) lead to the formation of the imido complexes [({eta}{sup 5}-C{sub 5}Me{sub 5})M(NR)Cl{sub 2}] (3a-h). X-ray structure analyses of 3a, 3c and 3e reveal their monomeric nature. 3c and 3e crystallize in the monoclinic space group. ({eta}{sup 5}-C{sub 5}Me{sub 5})W(NC{sub 6}F{sub 5})Cl{sub 2} (3g) decomposes in the presence of air to the half-sandwich tungsten (VI) imido complex ({eta}{sup 5}-C{sub 5}Me{sub 5}W(NC{sub 6}F{sub 5})Cl{sub 3}(4) and a green solid. Further hydrolysis of 3g results in the dinuclear tungsten(VI) oxo complex [({eta}{sup 5}-C{sub 5}Me{sub 5})WO{sub 2}]{sub 2}{mu}-O){center_dot}C{sub 6}F{sub 5}NH{sub 2}(5) with a linear W-O-W bridge. The complexes have been characterized by X-ray diffraction. 4 crystallizes in the triclinic space group; 5 crystallizes in the monoclinic space group.