Palladium-rhodium and platinum-rhodium heterobimetallic bridged dithiolate complexes of general formula [(P-P)M(&mgr;-S-S)Rh(COD)]ClO(4) (COD = 1,5-cyclooctadiene. For M = Pt: P-P = (PPh(3))(2) and S-S = EDT(2)(-) (1,2-ethanedithiolate) (1), PDT(2)(-) (1,3-propanedithiolate) (2), and BDT(2)(-) (1,4-buthanedithiolate) (3); P-P = dppb (1,4-bis(diphenylphosphino)butane) and S-S = EDT(2)(-) (4), PDT(2)(-) (5), and BDT(2)(-) (6); P-P = dppp (1,3-bis(diphenylphosphino)propane) and S-S = EDT(2)(-) (7), PDT(2)(-) (8), and BDT(2)(-) (9). For M = Pd: P-P = dppb and S-S = EDT(2)(-) (10), PDT(2)(-) (11), and BDT(2)(-) (12); P-P = dppp and S-S = EDT(2)(-) (13), PDT(2)(-) (14), and BDT(2)(-) (15)) have been prepared. The crystal structures for complexes 1-3, 6, 9, and 12 have been determined, and hinged structures were found with angles between local coordination planes MS(2)Rh ranging from 111.27 degrees for complex 1 to 151.34 degrees for complex 3. Metal-metal distances show nonbonding interactions between metals. X-ray data for 1: triclinic, P&onemacr;, a = 11.311(6) Å, b = 12.991(6) Å, c = 16.140(6) Å, alpha = 84.86(6) degrees, beta = 75.73(6) degrees, gamma = 86.43(6) degrees, Z = 2, R = 0.0427 (R(w) = 0.1151). X-ray data for 2: triclinic, P&onemacr;, a = 11.084(5) Å, b = 13.094(6) Å, c = 16.338(6) Å, alpha = 86.06(6) degrees, beta = 75.67(6) degrees, gamma = 88.55(6) degrees, Z = 2, R = 0.0470 (R(w) = 0.1264). X-ray data for 3: orthorhombic, Pbca, a = 14.439(6) Å, b = 19.807(6) Å, c = 38.156(6) Å, Z = 8, R = 0.0864 (R(w) = 0.2457). X-ray data for 6: monoclinic, P2(1)/c, a = 20.338(6) Å, b = 14.227(6) Å, c = 14.570(6) Å, beta = 100.94(6) degrees, Z = 4, R = 0.0536 (R(w) = 0.1449). X-ray data for 9: monoclinic, P2(1)/c, a = 20.326(6) Å, b = 14.109(6) Å, c = 14.368(6) Å, beta = 100.90(6) degrees, Z = 4, R = 0.0380 (R(w) = 0.0990). X-ray data for 12: monoclinic, P2(1)/c, a = 20.365(6) Å, b = 14.186(6) Å, c = 14.592(6) Å, beta = 101.04(6) degrees, Z = 4, R = 0.0507 (R(w) = 0.1500).

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Chiral 1,2-bis[tris(dimethylamino)phosphinimino]cyclohexane (7a, 80% yield), 1,2-bis[tris-(dimethylamino)phosphinimino]-1,2-diphenylethane (7b, 74% yield), 1,2-bis[triphenoxyphosphinimino]cyclohexane (9a, 85% yield), and 1,2-bis[triphenoxyphosphinimino]-1,2-diphenylethane (9b, 70% yield) have been prepared using (1R,2R)-1,2-diaminocyclohexane or (1R,2R)-1,2-diphenylethylenediamine and the corresponding phosphine dibromide derivatives (the Kirsanov route). 1,2-Bis[triphenylphosphinimino]cyclohexane (2), 1,2-bis[triphenylphosphinimino]-1,2-diphenylethane (3), and 1,2-diiminophosphoranes 7b and 9b reacted with [Pd(η 3 -C 3 H 5 )Cl] 2 in the presence of a silver salt in CH 2 Cl 2 at room temperature to afford the cationic complexes 10 (81% yield), 11 (84% yields), 15 (78% yield), and 16 (74% yield), respectively. According to the same general procedure, palladium complexes [(η 3 -PhCHCHCHPh)(2)Pd]TfO (13, 88% yield) and [(η 3 -PhCHCHCHPh)(3)Pd]TfO (14, 86% yield) have been prepared. Single-crystal X-ray diffraction studies of derivatives 10, 11, and 13 have been carried out. They revealed that C 2 symmetry was retained for derivative 3 upon coordination, but lost for 2 in the coordination sphere of the metal. 13 C NMR chemical shifts for the terminal C atoms of the allyl moiety of these complexes indicate that the donor ability of 1,2-diiminophosphoranes varies with the nature of the P-substituents and is comparable to that of other sp 2 -hybridized nitrogen ligands. 1,2-Diiminophosphoranes were evaluated as ligands for the Pd-catalyzed enantioselective allylic substitution reaction of rac-1,3diphenylprop-2-enyl acetate with the anion of dimethyl malonate. Ligands 3 and 7a,b induce good catalytic activities compared with other N,N-ligands but moderate ee's (10-77%) at 36 °C. Higher ee's (85%) were obtained at room temperature with ligand 3 but at the expense of the catalytic activity. This study revealed that 1,2-diimonophosphoranes are able to stabilize Pd(0) species during a catalytic process and to induce notable levels of enantioselectivity.