MANGANESE-GROUP 11 ELEMENT AND MANGANESE-ZINC MIXED-METAL CLUSTERS DERIVED FROM THE BINUCLEAR DIANION -2(MU-P(OET)(2))(MU-ETA(2)-OP(OET)(2))(CO)(6)](2-) - X-RAY STRUCTURES OF T)(2))(MU-ETA(2)-OP(OET)(2))(CO)(6)(C10H8N2-N,N')] AND [MN2AU3(MU-P(OET)(2))(CO)(6)(PPH(3))(3)]

The binuclear dianion -2{mu-P(OEt)(2)}{mu-eta(2)-OP(OEt)(2)}(CO)(6)](2 -) (as the Na+ salt) reacts readily in tetrahydrofuran at room tempera ture with the chloro complexes [ZnCl2(bpy)] or [MCl(PR(3))](n) (bpy = C10H8N2-N,N'; M = Au, Cu, R = Ph, Et; M Ag, R = Ph) to give the corres ponding trinuclear clusters n{mu-P(OEt)(2)}{mu-eta(2)-OP(OEt)(2)}(CO)( 6)(bpy)] or mu-P(OEt)(2)}{mu-eta(2)-OP(OEt)(2)}(CO)(6)(PR(3))] in high yield. The latter have been isolated as the corresponding tetraphenyl arsonium salts after ion exchange with [AsPh(4)]Cl in dichloromethane. The trinuclear anions (as Na+ salts) react with a second equivalent o f [MCl(PR(3))](n) in toluene, but the expected tetranuclear clusters P (OEt)(2)}{mu-eta(2)-OP(OEt)(2)}(CO)(6)(PR(3))(2)] are formed only for M = Au, Ag and have a low thermal stability. In the case of copper, el ectron transfer rather than metal-metal bond formation occurs. Decompo sition of the digold manganese clusters in the presence of [AuCl(PR(3) )] gives the unsaturated pentanuclear clusters [Mn2Au3{mu-P(OEt)(2)}(C O)(6)(PR(3))(3)] (R = Ph, Et) in low yields (10-15% at best). The stru cture of the latter (8a; R = Ph) and that of the dimanganese zinc clus ter (2) have been determined by X-ray diffraction methods. The structu res of the new compounds as well as the dynamic behavior or ion-pairin g effects in some of them are discussed on the basis of the IR and NMR (H-1, P-31) data. It is concluded that the P-31 chemical shift of the bridging diethoxyphosphido ligand in these and related manganese syst ems cannot be used as a reliable probe for the presence of a manganese -manganese bond.