Synthesis and Characterization of the Homologous M-M Bonded Series Ar'MMAr' (M = Zn, Cd, or Hg; Ar' = C6H3-2,6-(C6H3-2,6-Pri2)2) and Related Arylmetal Halides and Hydride Species.

The synthesis and structural characterization of the first homologous, mol. M-M bonded series for the group 12 metals are reported. The compds. Ar'MMAr' (M = Zn, Cd, or Hg; Ar' = C6H3-2,6-(C6H3-2,6-Pri2)2) were synthesized by redn. of the corresponding arylmetal halides by alkali metal/graphite (Zn or Hg) or sodium hydride (Cd). These compds. possess almost linear C-M-M-C core structures with two-coordinate metals. The obsd. M-M bonds distances were 2.3591(9), 2.6257(5), and 2.5738(3) Å for the zinc, cadmium, and mercury species, resp. The shorter Hg-Hg bond in comparison to that of Cd-Cd is consistent with DFT calcns. which show that the strength of the Hg-Hg bond is greater. The arylmetal halides precursors (Ar'MI)1 or 2, and the highly reactive hydrides (Ar'MH)1or2, were also synthesized and fully characterized by x-ray crystallog. (Zn and Cd) and multinuclear NMR spectroscopy. The arylzinc and arylcadmium iodides have iodide-bridged dimeric structures, whereas the arylmercury iodide, Ar'HgI, is monomeric. The arylzinc and arylcadmium hydrides have sym. (Zn) or unsym. (Cd) μ-H-bridged structures. The Ar'HgH species was synthesized and characterized by spectroscopy, but a satisfactory refinement of the structure was precluded by the contamination of monomeric Ar'HgH by Ar'H. It was also shown that the decompn. of Ar'Cd(μ-H)2CdAr' at room temp. leads to the M-M bonded Ar'CdCdAr', thereby supporting the view that the redn. of the iodide proceeds via the hydride intermediate. [on SciFinder(R)]