Reactions of Group 4 Metallocene Alkyne Complexes with Azobenzene: Formation of Diazametallacyclopropanes and N═N Bond Activation

The alkyne complex Cp 2 Zr(py)(η 2 -Me 3 SiC 2 SiMe 3 ) ( 1 ) (Cp = η 5 -cyclopentadienyl, py = pyridine) reacts with azobenzene to give the known diazene complex Cp 2 Zr(py)(N 2 Ph 2 ) ( 2 ). The same method was used to synthesize the new complexes rac -(ebthi)M(N 2 Ph 2 ) (ebthi = 1,2-ethylene-1,1′-bis(η 5 -tetrahydroindenyl), M = Ti ( 5 ), Zr ( 6 )) by alkyne exchange. The reaction of Cp* 2 Ti(η 2 -Me 3 SiC 2 SiMe 3 ) ( 7 ) (Cp* = η 5 -pentamethylcyclopentadienyl) and azobenzene gave the analogous diazene complex 8 and two different dinuclear complexes, 9 and 10, with two or three bridging phenylimido groups, respectively. The molecular structures of 6, 8, 9, and 10 were confirmed by X-ray crystallography and compared to former structural data shown in the literature.