The activation and transformations of vinyl acetate at a dirhenium carbonyl center

The reaction of Re-2(CO)(8)(mu-C6H5)(mu-H), 1 with vinyl acetate in methylene chloride by heating at 40 degrees C yielded three new products: Re-3(CO)(13)(mu-eta(2)-C2H3), 3, (24% yield), Re-2(CO)(8)(mu-eta(2)-O2CCH3)(mu-H), 4, (9% yield) and Re-2(CO)(8)(mu-eta(2)-CHCHO2CCH3)(mu-H), 5, (13% yield). Compound 3 was also obtained in a similar yield from the reaction of Re-2(CO)(8)(mu-H)[mu-eta(2)-C(H) = C(H)Bu-n], 2 with vinyl acetate, but compounds 4 and 5 were not obtained. All of the products were characterized structurally by single-crystal X-ray diffraction analysis. Compound 3 consists of an open trirhenium cluster containing two rhenium - rhenium bonds. One of the rhenium - rhenium bonds contains a mu-eta(2)-(sigma+pi)-coordinated C2H3 (vinyl) ligand. Compound 4 contains two rhenium atoms with a bridging eta(2)-acetate ligand and a bridging hydrido ligand. Compound 5 contains two mutually bonded Re-Re atoms with a bridging (sigma+pi)-coordinated acetate-substituted vinyl group and a bridging hydrido ligand by the cleavage of one of the CH bonds on the beta-carbon atom of the vinyl group of the vinyl acetate. The reaction of compound 3 with I-2 resulted in cleavage of the Re(CO)(5) group to yield the known complex Re(CO)(5)I and the new dirhenium complex Re-2(CO)(8)I(mu-eta(2)-C2H3), 6 containing a mu-eta(2)-(sigma+pi)-coordinated vinyl group. (C) 2019 Elsevier B.V. All rights reserved.