HYDROLYSIS OF TETRACHLORO(PENTAMETHYLCYCLOPENTADIENYL)NIOBIUM(V) - CRYSTAL-STRUCTURE OF [NB2(ETA-5-C5ME5)2CL2(MU-2-O)(MU-CL)](MU-2-O)2(MU-3-O)[NB(ETA-5-C5ME5)CL]

NbCp*Cl4 (1; Cp* = η5-C5Me5) is directly isolated as a crystalline solid by reacting NbCl5 with SiMe3(C5Me5) in dichloromethane-toluene (3:1). Complex 1 reacts with H2O in the presence of NHEt2 to give the mononuclear hydroxo complex NbCp*Cl3(OH) (2), which reacts with 1, losing HCl to give the μ-oxo complex [NbCp*Cl3]2(μ-O) (3), also formed by exposure of solid samples of 1 to the ambient atmosphere. 2 also reacts with H2O in solution to form the μ-oxo hydroxo complex [NbCp*Cl2(OH)]2(μ-O) (4), which is also formed from 3 by exposure to air. When the dinuclear complex 4 is heated, it yields the trinuclear niobium oxide cluster Nb3Cp*3-(μ2-O)3(μ3-O)(μ2-Cl)Cl3 (5). The crystal structure of 5 is reported. The compound crystallizes in the monoclinic space group P21/n, with Z = 4, a = 11.357 (6) Å, b = 19.685 (10) Å, and c = 15.797 (6) Å. Anisotropic refinement of all atoms except hydrogen atoms converged to the residuals R = 0.069 and Rw = 0.030 for 2722 reflections. © 1990, American Chemical Society. All rights reserved.