FACILE CONVERSION OF AN APPENDED SILYLAMIDO TO A SILYLOXY LIGAND VIA ISOCYANATE ELIMINATION - SYNTHESIS OF )ME(4))SIME(2)O]ZR(ETA(2)-O(2)CME)(MU-O(2)CME))(2) VIA THE CARBOXYLATION OF [(C(5)ME(4))SIME(2)(N-T-BU)]ZRME(2)

The reaction of 2 equiv of CO2 with [(C(5)Me(4))SiMe(2)(N-t-Bu)]ZrMe(2 ) proceeds with the formation of SiMe(2)(N-t-Bu)]Zr(eta(2)-O(2)CMe)(mu -O(2)CMe)}(2) (2), which reacts with additional CO2 to afford {[(C(5)M e(4))SiMe(2)O]Zr(eta 2-O(2)CMe)(mu-O(2)CMe)}(2) (3) with the concomita nt elimination of OCN-t-Bu. The formation of OCN-t-Bu was confirmed by a combination of GC/MS and IR measurements; the molecular structures of 2 and 3 were determined by X-ray crystallography.