Isolation of a stable precursor for [Pt0(P-P)] and its reductive addition to Ru3(CO)9(μ3-S)2 giving square heterometallic clusters supported by two face-capping μ4-sulfides [P-P = (C5H4PPh2)2M;: M = Fe, Ru]

Two labile but air-stable Pt(0) complexes Pt(eta(2)-P-P)(eta(2)-dba) [dba = dibenzylideneacetone; P-P = 1,1'-bis(diphenylphosphino)ferrocene (dppf) (3a) or 1,1'-bis(diphenylphosphino)ruthenocene (dppr) (3b)] were prepared from Pt-2(dba)(3) (1) and the corresponding metallocenyl diphosphine. Reductive addition of 3 to Ru-3(CO)(9)(mu(3)-S)(2) (4) gave good yields of two novel square clusters PtRu3(CO)(6)(mu-CO)(2)(eta(2)-P-P)(mu(4)-S)(2) [P-P = dppf (5a) or dppr (5b)]. A one-pot reaction mixture containing 1, 4, and the diphosphine (2) gave Ru-3(CO)(7)(mu-P-P)(mu(3)-S)(2) [P-P = dppf(6a) or dppr (6b)] along with 5a and 5b. All products have been characterized by IR, H-1, and P-31{H-1} NMR. In addition, X-ray crystal analyses were also performed on complexes 3a, 5a, 5b, and 6a. 3a is a planar Pt(0)-olefin complex stabilized by chelating dppf and a trans,trans-dba moiety coordinated via a C=C functionality. Compounds Sa and 5b are rare examples of almost regularly octahedral heterometallic square clusters with two mu(4)-S ligands above and below the PtRu3 plane.