STRUCTURAL CHARACTERIZATION OF CO2(CO)5[P(C6H5)3](MU-P2) - TRICYCLIC COMPLEX CONTAINING A BRIDGING P-2 LIGAND

A three-dimensional single-crystal X-ray structural determination of Co2(CO)5[P(C6H5)3](p-P2), a mono(triphenylphosphine)-substituted derivative of Co2(CO)6(μ-P2), has revealed the first known example of a transition-metal complex with a diphosphide ligand symmetrically bonded to two metal atoms. Crystals of Co2(CO)5[P(C6H5)3](μ-P2) are triclinic with space group P1 and lattice constants a = 10.467 (3) Å, b = 12.785 (3) Å, c = 10.186 (3) Å, α = 108.76 (2)°, β = 99.80 (2)°, and γ = 82.10 (2)°; pobsd = 1.50 g/cm3 vs. pcalcd = 1.53 g/cm3 for Z = 2. Least-squares refinement gave R1(F) = 6.7% and R2(F) = 7.4% for 1532 independent reflections with I > 2.5σ(I). The Co2P2 core of the molecule possesses an idealized C2v geometry with a Co-Co bond distance of 2.574 (3) Å, a P-P bond length of 2.019 (9) Å, and an average Co-P bond length of 2.264 (5) Å. The molecular configuration of Co2(CO)5[P(C6H5)3](μ-P2) is compared with those of Fe2(CO)6(μ-S2) and Co2(CO)5[P(C6H5)3](μ-As2). © 1979, American Chemical Society. All rights reserved.