Treatment of (EBTHI)MCl2 [M = Zr, 1; M = Hf, 2; EBTHI = ethylene-1,2-bis(eta-5-4,5,6,7-tetrahydro-1-indenyl)] with 2 equiv of NaEt3BH in C6H6 produces the hydride dimers [(EBTHI)MH(mu-H)]2 (M = Zr, 3; M = Hf, 4). The dimethylhafnium complex (EBTHI)HfMe2 (5) is formed when 2 is treated with MeLi in C6H6. Complexes 3 and 4 can be protonated with the weak acid [PhMe2NHT[Co(C2B9H11)2] to give monomeric cationic hydrides [(EBTHI)M(H)(NPhMe2)][Co(C2B9H11)2] (M = Zr, 6; M = Hf, 7), in which the N,N-dimethylaniline ligand is very weakly coordinated to the metal. Improved syntheses of the dichloride complexes 1 and 2 are also described.
“Syntheses of [ethylene-1,2-bis(.eta.5-4,5,6,7-tetrahydro-1-indenyl)]zirconium and -hafnium hydride complexes. Improved syntheses of the corresponding dichlorides”, Organometallics, 1991, 10(5), 1501-1505.