Addition of platinum and palladium tri-tert-butyl phosphine groups to open Pt-Fe and Pt-Ru metal carbonyl clusters

Two series of new compounds, Pt3Fe3(CO)(15)[M(PBu3t)] (M = Pt, 12; M = Pd, 14) and Pt3Fe2(CO)(12)[M(PBu3t)](2) (M = Pt, 13; M = Pd, 15), were synthesized from the reactions of Pt(PBu3t)(2) and Pd(PBu3t)(2) with Pt3Fe3(CO)(15), 9. All new compounds were characterized crystallographically. Compounds 12 and 14 are structurally similar and contain a M(PBu3t) group bridging a triangular Pt2Fe group of the starting complex 9. These compounds can be viewed as adducts of 9 because there was no loss of carbonyl ligands during the course of the addition reaction. Compounds 13 and 15 are also structurally similar and contain two mutually bonded M(PBu3t) groups. These metal atoms are part of a Pt2M2 tetrahedron that also contains an edge-bridging platinum atom and two Fe(CO)(4) groups that bridge the Pt-Pt bonds to this edge-bridging platinum. These compounds can be formed from 12 and 14 by replacement of one Fe(CO)3 group with a M(PBu3t group. The M-M bond is stabilized by a bridging carbonyl ligand. The reaction of Pt(PBu3t)(2) with Pt2Ru4(CO)(18), 11, afforded the complex Pt2Ru4(CO)(17)[Pt(PBu3t)], 16. Compound 16 contains an M(PBu3t) group that has formed a quadruple bridge across a Ru2Pt2 butterfly of the parent cluster 11.