Heterometallic Osmium-Mercury Chain Structures Linking Two {Os(3)(CO)(10)(&mgr;-X)} Subunits (X = Cl, Br, I): Syntheses and Molecular Structures of [{Os(3)(CO)(10)(&mgr;-X)}(2)(&mgr;(4)-Hg)] (X = Cl, I), [{Os(3)(CO)(10)(&mgr;-Cl)}(2){&mgr;-HgOs(CO)(4)}(2)], and cis-[Os(CO)(4){(&mgr;-Hg)Os(3)(CO)(10)(&mgr;-Cl)}(2)].
Treatment of RHgCl (R = Me, Et, Ph, Fc) with the activated cluster [Os(3)(CO)(10)(NCMe)(2)] produces the osmium-mercury mixed-metal clusters [{Os(3)(CO)(10)(&mgr;-Cl)}(2)(&mgr;(4)-Hg)] (1a) and [{Os(3)(CO)(10)(&mgr;-Cl)}(2){&mgr;-HgOs(CO)(4)}(2)] (2a) in low yields. Cluster 1a bears a central wingtip mercury atom simultaneously bridging two {Os(3)(CO)(10)(&mgr;-Cl)} units. Cluster 2a comprises an unprecedented decanuclear osmium-mercury framework in which there is a central linear "Hg-{Os(CO)(4)}(2)-Hg" molecular backbone with the two Os(CO)(4) fragments arranged in a staggered conformation. Cluster 2a is thermally unstable and converts slowly to cis-[Os(CO)(4){(&mgr;-Hg)Os(3)(CO)(10)(&mgr;-Cl)}(2)] (4a) via the extrusion of an Os(CO)(4) moiety under ambient conditions. Cluster 4a comprises two {(&mgr;-Hg)Os(3)(CO)(10)(&mgr;-Cl)} subcluster units bonded to a central Os(CO)(4) moiety in a cis configuration. Similar reactions with PhHgBr and MeHgI have also been investigated. Cluster 1a crystallizes in the triclinic space group P&onemacr; with a = 9.112(2) Å, b = 12.314(2) Å, c = 15.501(4) Å, alpha = 84.92(2), degrees beta = 88.26(3), degrees gamma = 79.52(2) degrees and Z = 2. Cluster 2a crystallizes in the triclinic space group P&onemacr; with a = 13.306(2) Å, b = 20.768(5) Å, c = 9.771(4) Å, alpha = 96.36(3), degrees beta = 90.50(2), degrees gamma = 98.81(2) degrees and Z = 2. Cluster 4a crystallizes in the triclinic space group P&onemacr; with a = 18.356(2) Å, b = 19.100(3) Å, c = 14.478(2) Å, alpha = 89.783(2), degrees beta = 113.19(2), degrees gamma = 113.70(2) degrees and Z = 4.
Au
Yat-Kun
YK
Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
Wong
Wing-Tak
WT