Syntheses and structures of highly hindered N-functionalised alkyl and amido group 12 complexes MR2 (M=Zn, Cd, and Hg), [MRCl]2 (M=Zn and Hg)

The reaction of MCl2 (M=Zn, Cd and Hg) with Li(2-(C(SiMe3)2)(6-Me–C5H3N)), [Li(MeR)], affords mononuclear metal(II) alkyls. These, in the solid state, show intramolecular M–N interactions in their four-membered chelate rings, which progressively weaken down the series, the C–M–C angles becoming more open (〈M–N〉= 2.30(2), 2.52(2), 2.913(4) Å, C–M–C=160.7(2), 168.5(2), 180(-)°). Alkylmercury chloride complexes have been prepared by the reaction of HgCl2 with [Li(MeR)], Li(2-(C(SiMe3)2)(C5H4N)), [Li(HR)], or Li(2-(NSiMe3)(6-Me–C5H3N)), [Li(mpsa)], or from the redistribution reaction of the dialkyl (or amido) mercury complex with HgCl2. The alkylmercury chloride complexes are dimeric or polymeric in nature with near-linear 2-coordination; (Hg–Cl=2.329(5), 2.318(4), 2.272(8) Å, Cl–Hg–C(N)=175.0(4), 174.7(4), 175.6(5)°). Cd(2-(CH(SiMe3))(6-Me-C5H3N))2(tmen), prepared from the reaction of Li(2-(CH(SiMe3))(6-Me–C5H3N)) and CdCl2 in the presence of tmen, has also been structurally authenticated as the rac isomer with the ipso protons directed towards the tmen.Treatment MCl2 (M = Zn, Cd and Hg) with two equivalents of Li(2-(C(SiMe3)2)(6-Me–C5H3N)), affords mononuclear metal(II) alkyls. These, in the solid state, show intramolecular M–N interactions in their four-membered chelate rings, which progressively weaken down the series. Similar treatment of HgCl2 with one equivalent of Li(2-(C(SiMe3)2)(6-Me–C5H3N)), Li(2-(C(SiMe3)2)(C5H4N)), or Li(2-(NSiMe3)(6-Me–C5H3N)), afford the corresponding alkyl- or amido mercury chloride. These, in the solid state are dimeric or polymeric in nature with near-linear 2-coordination.