trans-Acetyl-dicarbon-yl(η(5)-cyclo-penta-dien-yl)(methyl-diphenyl-phosphane)molybdenum(II).

The title compound, [Mo(C(5)H(5))(C(2)H(3)O)(C(13)H(13)P)(CO)(2)], was prepared by reaction of [Mo(CH(3))(C(5)H(5))(CO)(3)] with methyl-diphenyl-phosphane. The Mo(II) atom exhibits a four-legged piano-stool coordination geometry with the acetyl and phosphane ligands trans to each other. There are several inter-molecular C-H⋯O hydrogen-bonding inter-actions involving carbonyl and acetyl O atoms as acceptors. A close nearly parallel π-π inter-action between the cyclo-penta-dienyl plane and the phenyl ring of the phosphane ligand is present, with an angle of 6.4 (1)° between the two least-squares planes. The centroid-to-centroid distance between these groups is 3.772 (3) Å, and the closest distance between two atoms of these groups is 3.449 (4) Å. Since each Mo complex is engaged in two of these inter-actions, the complexes form an infinite π-stack coincident with the a axis.