Syntheses, structures, and bonding of CP2M(ER)2 compounds (CP = C5H5; M = Ti, Zr; E = Ga, In; R = C6H3-2,6-(2,4,6-i-Pr3C6H2)2)

Sodium or magnesium metal reduction Of Cp2MCl2 (Cp = C5H5; M = Zr, Ti) with RECl6 (E = Ga. In; R = C6H3-2,6-(2,4,6-i-Pr3C6H2)(2)) affords heteronuclear organometallic compounds, Cp2M(ER)(2), With new types of group 4-group 13 M-E bonds (Zr-Ga (1), Ti-Ga (2), Zr-In (3), Ti-In (4)). These compounds have been characterized by elemental analyses, H-1 and C-13 NMR spectroscopy, and single-crystal X-ray diffraction analyses. The structures of 1-4 have V-shaped E-M-E trimetallic linkages with quite short M-E bonds (Zr-Ga, 2.6350(8) angstrom; Ti-Ga, 2.492](7) angstrom; Zr-In, 2.7916(5) angstrom. Ti-In, 2.6685(8) angstrom). The transition metal (M = Zr. Ti) centers adopt a pseudo-tetrahedral coordination geometry, while the main group metal (E = Ga, In) atoms reside in a two-coordinate, almost linear environment. Density functional theory (DFT) computations oil the model compounds Cp2M(EPh)(2) (1Ph-4Ph) suggest significant pi-back-bonding from the group 4 metals (Zr, Ti) to the group 13 metals (Ga, In) in these compounds.