Group 13 ligand supported heavy-metal complexes: First structural evidence for gallium-lead and gallium-mercury bonds

Heavy-metal complexes of lead and mercury stabilized by Group 13 ligands were derived from the oxidative addition of Ga(ddp) (ddp = HC(CMeNC ₆H₃2,6-iPr₂)2, 2-diisopropylphenylamino-4- diisopropyl phenylimino-2-pentene) with corresponding metal precursors. The reaction of Me₃PbCl and Ga(ddp) afforded compound' [{(ddp)Ga(Cl)}PbMe₃] (1) composed of Ga-Pb^Iv bonds. In addition, the monomeric plumbylene-type compound [{(ddp)Ga(OSO ₂CF₃)}:Pb(thf)] (2a) with an unsupported GaPb ^II-Ga linkage was obtained by the re-action of [Pb(OSO ₂CF₃)₃] with Ga(ddp) (2 equiv). Compound 2a falls under the rare example of a discrete plumbylene-type compound supported by a nonclassical ligand. Interesting structural changes were observed when [Pb(OSO₂CF₃)₃]·2H₂O was treated with Ga(ddp) in a 1:2 ratio to yield [{(ddp)Ga(μ-OSO ₂CF₃)}₂(OH₂)Pb] (2b) at below -10°C. Compound 2b consists of a bent Ga-Pb-Ga backbone with a bridging triflate group between the Ga-Pb bond and a weakly interacting water molecule at the gallium center. Similarly, the reaction of mercury thiolate Hg(SC ₆F₅) with Ga(ddp) (2 equiv) produced the bimetallic homoleptic compounds anti-[{(ddp)Ga(SC₆F₅)}₂Hg] (3a) and gauche[{(ddp)Ga(SC₆F₅)}₂Hg] (3b), respectively, with a linear Ga-Hg-Ga linkage. Compounds 1-3 were structurally characterized and these are the first examples of compounds comprised of GaPb^II, Ga-Pb^Iv, and Ga-Hg bonds.