Cyclopentadienyl replacement by trispyrazolylborate and the syntheses of M(η5-C5H5){HB(C3H3N2)3}X2 (M = Hf, X = Cl; M = Zr, X = Cl, OPh, OC6H4-4-NO2, OC6H4-4-OMe, OC6H4-2-Ph)

Abstract The reactions between M{C 5 H 5 } 2 Cl 2 (M = Zr, Hf) and HB(C 3 H 3 N 2 ) 3 H afford M (η 5 -C 5 H 5 ){HB(C 3 H 3 N 2 ) 3 }Cl 2 . These compounds undergo halide substitution reactions with phenols and the new complexes Zr(η 5 -C 5 H 5 ){HB(C 3 H 3 N 2 ) 3 }X 2 (X = Cl, OC 6 H 4 Z; Z = H, 4-NO 2 , 4-OMe, 2-Ph) have been isolated and characterized.