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

In pentacarbonyl(4-phenylpyridine)tungsten(0), [W(C11H9N)-(CO)(5)], the mol ecules have mm site symmetry and the pyridine ligand, with m symmetry, is c ompletely planar. In pentacarbonyl(2-phenylpyridine)chromium(0), [Cr(C11H9N )-(CO)(5)], the molecules are in general positions and the phenyl and pyrid ine rings of the ligand are twisted by 67.7 (3)degrees with respect to one another by rotation about the CDC bond joining them. In both compounds, the axial M-C-carbonyl bond trans to the M-N-ligand bond is significantly shor ter than the equatorial M-C-carbonyl bonds.