THE REACTION OF Ru3(CO)12 AND Os3(CO)12 WITH PH2Ph; THE X-RAY CRYSTAL STRUCTURES OF HRu3(CO)10(PHPh) AND H2Ru3(CO)9(PPh)

Article abstract of DOI:10.1016/S0022-328X(00)93959-7

Twelve new trinuclear complexes containing terminal PH2Ph, edge-bridging PHPh and/or capping PPh ligands have been isolated from the reaction of M3(CO)12 (M=Ru or Os) with PH2Ph in refluxing solvents.HRu3(CO)10(PHPh) (IIIa) crystallises in the monoclinic space group P2₁/c with a=8.761(3), b=11.402(4), c=22.041(7) Angstroem, β=98.89(2)deg, and Z=4.The structure was solved by a combination of direct methods and Fourier difference techniques, and refined by blocked-cascade least squares to R=0.027 for 3676 unique observed intensities.The X-ray analysis shows that one edge of the Ru3 triangle is bridged by a hydride and the PHPh ligand, and that the phosphorus-bound hydrogen atom lies over the metal triangle and the phenyl group away from it.This provides an explanation for the ready formation of the capped species H2Ru3(CO)9(PPh) (Va) on pyrolysis of the edge-bridged complex as opposed to the previously reported conversion of HOs3(CO)10(NHPh) to an orthometallated derivative under similar conditions.An X-ray analysis of H2Ru3(CO)9(PPh) (Va) confirms the capped geometry.The complex crystallises in the monoclinic space group P2₁/n with a=9.323(4), b=15.110(6), c=45.267(15) Angstroem, β=91.84(3) deg, and Z=12.The structure was solved and refined using the same techniques as described previously.The final residual R is 0.061 for 4839 reflections.Some reactions of Va show that the phosphorus cap is difficult to displace and stabilises the molecule with respect to decomposition to non-cluster species.