A (ETA-1-IMINOACYL)ZIRCONOCENE COMPLEX FORMED BY ALKYL ISOCYANIDE INSERTION INTO THE METAL TO CARBON BOND OF (ETA-2-FORMALDEHYDE)ZIRCONOCENE

The (eta-2-formaldehyde)zirconocene complex (Cp2ZrOCH2)2 (1) reacts with alkyl isocyanides CN-R (2a-c) (R = -CH2SiMe3, -CH2CMe3, -CMe2CH2CMe3) to give the insertion products [Cp2ZrOCH2C(= NR)]2 (3a-c). The doubly oxygen bridged C2h-symmetric metallatricyclic complexes 3 contain (eta-1-imioacyl)zirconocene moieties. The (trimethylsily)methyl isocyanide insertion product 3a was characterized by X-ray diffraction. It crystallizes in space group P1BAR with cell parameters a = 7.977 (1) angstrom, b = 10.162 (1) angstrom, c = 11.753 (1) angstrom, alpha = 64.53 (1)-degrees, beta = 85.27 (1)-degrees, gamma = 79.89 (1)-degrees, Z = 1, R = 0.024, and R(w) = 0.035. The C = N bond length in 3a is 1.274 (2) angstrom; the Zr-C distance of the (eta-1-iminoacyl)zirconocene moiety is 2.374 (1) angstrom.