Syntheses and structures of Zr4 tetrahedral clusters containing direct Zr-Zr bonds: the missing cluster in the series Zr(n) (n = 2-6).

The reduction of [(μ(2)-H)( μ(3)-H)(Cp*ZrCl)](4) by excess Na/Hg led to the isolation of the mixed-valence Zr(III)/Zr(IV) Zr(4) cluster [(μ(2)-H)(8)(μ(2)-Cl)(2)(Cp*Zr)(4)], 1, and the Zr(II)/Zr(III) Zr(4) cluster [(μ(2)-H)(6)(Cp*Zr)(4)], 2. The proton NMR data supports the diamagnetic property of both clusters in solution and the solid state structure of each cluster revealed a distorted tetrahedral skeleton comprised of four Zr atoms and the presence of direct Zr-Zr bonds. The hydride-bridged Zr-Zr bond distances are in the range of 3.

Novel micro3-oxo complexes prepared from Cp*Zr(B(3R)3 (R = H, CH3) and B(C6F5)3 in diethyl ether.

From the reactions of Cp*ZrCl(3) with 3 equiv. of LiBH(3)R (R = CH(3), Ph), the organotrihydroborate complexes, Cp*Zr(BH(3)CH(3))(3), 1, and Cp*Zr(BH(3)Ph)(3), 2, were isolated. One of the Zr-H-B bonding interactions in 2 could be described as an intermediate case between the bidentate and tridentate modes.