SYNTHESIS AND CRYSTAL-STRUCTURE OF THE COMPLEX [MOW(OET)(MU-CH2)(MU-C(C6H4ME-4)C(ME)O)(ETA-7-C7H7)(ETA-5-C2B9H10ME)]

The complex ]MoW(mu-CC6H4Me-4)(CO)2(eta-7-C7H7)(eta-5-C2B9H10Me)[ reacts with diazomethane in Et2O containing EtOH to afford the dimetal compound ]MoW(OEt)(mu-CH2){mu-C(C6H4Me-4)C(Me)O}(eta-7-C7H7)(eta-5-C2B9H10Me)[. The structure of this product was established by X-ray diffraction. The Mo-W bond ]2.778(4) angstrom[ is bridged by a CH2 group ]mu-C-Mo 2.14(3), mu-C-W 2.02(3) angstrom[ and by a C(C6H-4Me-4)C(Me)O fragment ]Mo-O 2.11(3), W-O 2.18(2), Mo-C(C6H4Me-4) 2.41(3), W-C9C6(C6H4Me-4) 2.09(3), Mo-C(Me) 2.26(3) 2.256(3) angstrom]. The molybdenum atom is eta-7-coordinated by the C7H7 ring and the tungsten atom is eta-5-coordinated by the open pentagonal face of the nido-icosahedral C2B9H10Me cage. The tungsten atom also carries a terminally bound OEt group [W-O 1.88(3) angstrom]. The H-1 and C-13{H-1} NMR data for the dimetal compound are reported and discussed.