Synthesis and structure of the mercury hydride compound, [TismPriBenz]HgH: a complete series of congeneric terminal hydride compounds of zinc, cadmium and mercury.

The terminal mercury hydride compound, [TismPriBenz]HgH, which features the tris[(1-isopropylbenzimidazol-2-yl)dimethylsilyl]methyl ligand, has been synthesized via the reaction of the triphenylsiloxide compound, [TismPriBenz]HgOSiPh3, with PhSiH3. The molecular structure of [TismPriBenz]HgH has been determined by X-ray diffraction in two crystalline forms, thereby completing the congeneric series of monomeric terminal hydride compounds of zinc, cadmium and mercury. NMR spectroscopic evidence for the terminal mercury hydride compound is provided by signals at δ 10.55 and δ -680 ppm in the 1H and 199Hg NMR spectra, respectively. Significantly, these signals exhibit a 1 J 199Hg-H coupling constant of 4546 Hz, which is considerably larger than the values that have been reported for other compounds. [TismPriBenz]HgH is also characterized by an absorption that is attributable to ν Hg-H at 1928 cm-1 in the IR spectrum.