Syntheses and structures of metallocene methyltrihydroborate derivativies: Cp2ZrCl[(mu-H)2BHCH3], Cp2Zr[(mu-H)2BHCH3]2, and Cp2Ti[(mu-H)2BHCH3

In reactions of zirconocene dichloride, Cp(2)ZrCl(2), with 1 equiv and an excess amount of LiBH(3)CH(3), the methyltrihydroborate complexes, Cp(2)ZrCl(mu-H)(2)BHCH(3)], 1, and Cp(2)Zr(mu-H)(2)BHCH(3)](2), 2, were isolated. The reaction of titanocene dichloride, Cp(2)TiCl(2), with an excess amount of LiBH(3)CH(3) produced the monosubstituted methyltrihydroborate complex, Cp(2)Ti(mu-H)(2)BHCH(3)], 3. The titanium was reduced from Ti(IV) to Ti(III), producing a 17-electron, paramagnetic titanocene complex. Under a dynamic vacuum at room temperature, compound 2 decomposed and produced the zirconium hydride compound Cp(2)ZrH(mu-H)(2)BHCH(3)]. Single crystal X-ray structures of 1, 2, and 3 were determined. Crystal data for 1: space group P2(1)/c, a = 13.7921(3) A, b = 13.4227(3) A, c = 13.0868(3) A, beta = 91.6448(12) degrees, Z = 8. Crystal data for 2: space group Pna2(1), a = 15.2949(4) A, b = 9.3417(2) A, c = 9.3211(2) A, Z = 4. Crystal data for 3: space group Fmm2, a = 9.1795(3) A, b = 13.0993(5) A, c = 8.8520(3) A, Z = 4.