REACTIVITY OF [MN2(MU-H)2(CO)6(MU-TEDIP)] (TEDIP=(ETO)2POP(OET)2) WITH GROUP 11 ALKYNYL COMPOUNDS - X-RAY STRUCTURES OF [AG2MN4(MU-H)6(CO)12(MU-TEDIP)2] AND [AUMN4(MU-H)5(CO)12(MU-TEDIP)2]

The unsaturated dihydride [Mn2(mu-H)2(CO)6(mu-tedip)] (1; tedip = (EtO )2POP(OEt)2) reacts at room temperature with [M(C=CPh)]n (M = Cu, Ag) to give a mixture of the hydrido alkynyl complex [Mn2(mu-H)(mu-eta1:et a2-(C=CPh)(CO)6(mu-tedip)] (4) and the corresponding hexanuclear clust ers [M2Mn4(mu-H)6(CO)12(mu-tedip)2] (M = Cu (2), Ag (5)), all displayi ng fluxional behavior in solution. In contrast, reaction of 1 with [Au (C=CPh)]n yields the pentanuclear cluster [AuMn4(mu-H)5(CO)12(mu-tediP )2] (6), also fluxional, along with complex 4. The structures of clust ers 5 and 6 have been determined by X-ray diffraction methods. Crystal s of 5 are triclinic, space group P1BAR, with Z = 1 in a unit cell of dimensions a = 14.014(9) angstrom, b = 9.272(7) angstrom, c = 10.741(6 ) angstrom, alpha = 102.91(2)-degrees, beta = 107.01(2)-degrees, and g amma = 103.37(2)-degrees. The structure has been solved from diffracto meter data by Patterson and Fourier methods and refined by full-matrix least squares on the basis of 3027 observed reflections to R and R(w) values of 0.0547 and 0.0622, respectively. Complex 5 is centrosymmetr ic and exhibits a planar Ag2Mn4 core consisting of a Ag2Mn2 lozenge wi th two further Mn atom 'spikes' in the plane of the Ag atoms. The Ag-A g bond distance is 2.800(2) angstrom, whereas the three Ag-Mn bond dis tances are rather different, 2.751(2), 2.902(2), and 3.050(2) angstrom ; the Mn-Mn separations of 3.312(3) angstrom are rather long and are p robably indicative of a very small direct bonding interaction between manganese atoms. Even though an accurate location of the hydrides was not possible, there is substantial evidence that four of them bridge A g-Mn edges and two triply bridge the Mn2Ag faces. Crystals of 6 are tr iclinic, space group P1BAR, with Z = 2 in a unit cell of dimensions a = 18.356(7) angstrom, b = 11.952(5) angstrom ,c = 11.688(5) angstrom, alpha = 74.37(2)-degrees, beta = 78.86(2)-degrees, and gamma = 83.42)2 )-degrees. The structure has been solved from diffractometer data by P atterson and Fourier methods and refined by full-matrix least squares on the basis of 5266 observed reflections to R and R(w) values of 0.04 33 and 0.0471, respectively. The metal core of complex 6 consists of t wo AuMn2 triangles sharing the common Au vertex and tilted by 21.1(1)- degrees. The two Mn-Mn separations are different, 2.860(2) and 3.080(2 ) angstrom. There is strong evidence that three hydrides bridge the ed ges of the triangle with the longer Mn-Mn distance, whereas the other triangle supports a triply bridging hydride and an edge-bridging (Mn-M n) hydride. In contrast with the previous reactions, [Mn2(mu-H)2(CO)6- (mu-tedip)] and [Au(C=CR)(PR'3)) (R = Ph, R' = p-tol; R = (t)Bu, R' = Ph) give the trimetallic clusters {mu-Au(PR'3)}(mu-eta1:eta2-CH=CHR)(C O)6(mu-tedip)] in good yields, having trans-alkenyl ligands, as indica ted by NMR data.