Pentacarbonyl(4-phenylpyridine)-tungsten(0) and pentacarbonyl-(2-phenylpyridine)chromium(0)

In pentacarbonyl(4-phenylpyridine)tungsten(0), [W(C₁₁H₉N)-(CO)₅], the molecules have mm site symmetry and the pyridine ligand, with m symmetry, is completely planar. In pentacarbonyl(2-phenylpyridine)chromium(0), [Cr(C₁₁H₉N)-(CO)₅], the molecules are in general positions and the phenyl and pyridine rings of the ligand are twisted by 67.7 (3)° with respect to one another by rotation about the C-C bond joining them. In both compounds, the axial M-C_carbonyl bond trans to the M-N_ligand bond is significantly shorter than the equatorial M-C_carbonyl bonds.