Phosphino-Stibine Ligands for the Synthesis of Heterometallic Complexes

Abstract

The phosphino-stibine ligands (o-PPh2C6H4)2SbR [R = o-PPh2C6H4 (L1), Ph (L2), Cl (L3)] were incorporated into tungsten and molybdenum carbonyl complexes leading to the formation of cis-[W(CO)4{(o-PPh2C6H4)2SbR}] [R = o-PPh2C6H4 (1), Ph (2), Cl (3)], fac-[W(CO)3{(o-PPh2C6H4)3Sb}] (4), fac-[W(CO)3{(o-PPh2C6H4)2SbCl}] (5), fac-[(W(CO)3{(o-PPh2C6H4)2Sb})2] (6), fac-[Mo(CO)3{(o-PPh2C6H4)2SbR}] [R = o-PPh2C6H4 (7), Ph (8), Cl (9)]. Compounds 1 and 4 were allowed to react with MX salts with M = Cu, Ag, Au and X = Cl–, [PF6]–, respectively. These reactions yielded cis-[W(CO)4{(o-PPh2C6H4)3Sb}{MCl}] [M = Cu (10), Ag (11)], cis-[W(CO)4{(o-PPh2C6H4)2Sb}{AuCl(o-PPh2C6H4)}{AuCl}] (12) cis-[(W(CO)4{(o-PPh2C6H4)2Sb})2AuCl] (13), cis-[W(CO)3(μ-CO){(o-PPh2C6H4)3Sb}{Cu}][PF6] (14), cis-[W(CO)4{(o-PPh2C6H4)3Sb}{AgMeCN}][PF6] (15), cis-[W(CO)4{(o-PPh2C6H4)3Sb}{Au}][PF6] (16) cis-[W(CO)2(μ-CO){(o-PPh2C6H4)3Sb}{Cu2(μ-Cl)2}] (17), fac-[W(CO)3{(o-PPh2C6H4)3Sb}{AuCl}] (18), and fac-[W(CO)2(μ-CO){(o-PPh2C6H4)3Sb}{ML}][PF6] [M = Cu, L = MeCN (19), M = Ag, L = MeCN (20), M = Au (21)]. Complexes 10–21 all show metal-metal distances below the sum of the corresponding van der Waals radii. The proximity of the two metal centers is especially significant in 19–21, indicating the presence of metal-metal bonding.