Mixed-metal cluster chemistry 25 Mixed ligand derivatives of MoIr3(mu-CO)(3)(CO)(8)(eta-C5R5) (R = H, Me) and Mo2Ir2(mu-CO)(3)(CO)(7)(eta-C5H5)(2); X-ray crystal structures of MoIr3(mu-CO)(3)(CO)(6)(PPh3)(2)(eta-C5Me5) and Mo2Ir2(mu(4)-eta(2)-PhC2Ph)

摘要

Reactions of MoIr3(mu-CO)(3)(CO)(8)(eta-C5Me5) (1) with stoichiometric amounts of the isocyanide Bu'NC afford the ligand substituted clusters MoIr3(mu-CO)(3)(CNBu')(n)(CO)(8-n)(eta-C5Me5) (n = 1 (2), 2 (3), 3 (4)) in fair to good yields (13-58%). In contrast, 1 reacts with PPh3 to afford a single unexpected product, namely MoIr3(mu-CO)(3)(CO)(6)(PPh3)(2)(eta-C5Me5) (5). A single-crystal X-ray study of 5 reveals that the phosphines occupy coordination sites adjacent to the plane of bridging carbonyls in a radial-radial-axial conformation previously unobserved in structural studies of molybdenum-tri-iridium or tungsten-tri-iridium clusters. Reactions of Mo2Ir2(mu-CO)(3)(CO)(7)(eta-C5H5)(2) (6) with Bu'NC or diphenylacetylene proceed cleanly in high yield to afford Mo2Ir2(mu-CO)(2)(CNBu')(2)(CO)(6)(eta-C5H5)(2) (7) or Mo(2)IrA(mu(4)-eta(2)-PhC2Ph)(mu-CO)(4)(CO)(4)(eta-C5H5)(2) (8), respectively; reacting 7 with diphenylacetylene or 8 with Bu'NC results in a more complex mixture of products from which Mo2Ir2(mu(4)-eta (2)-PhC2Ph)(mu-CO)(4)(CNBu')(CO)(3)(eta-C5H5)(2) (9) can be isolated in low yield. (C) 2003 Elsevier B.V. All rights reserved. [References: 22]