The crystal and molecular structure of cis-1,2-difluorovinylpentacarbonylmanganese

Abstract

Crystals of cis-1,2-difluorovinylpentacarbonylmagnanese, CFHCF·Mn(CO)₅, are monoclinic, a 6·32, b 13·94, c 10·89 Å, β 90·5°, space group P2₁/n. The structure was refined by least-squares methods, the final R being 0·17 for 696 reflexions. The structure contains discrete cis-CFHCF·Mn(CO)₅ molecules, the manganese atom being co-ordinated octahedrally to five carbonyl groups and one difluorovinyl group. The plane of the CFHCF– group is perpendicular to the adjacent square-plane of carbonyl groups, and is staggered with respect to the Mn–C bonds. Deviations from octahedral regularity are discussed. The Mn–C distance to the CFHCF– group (1·95 Å) is significantly longer than the Mn–CO lengths, and the apical Mn–carbonyl bond (1·73 Å) is possibly a little shorter than the other four (1·77–1·83, mean 1·79 Å). The C–F bonds (1·48 Å) are longer than normal. The intermolecular distances correspond to van der Waals interactions, most of the shorter contacts involving fluorine atoms.