Syntheses, characterization and molecular structures of monomeric selenolato complexes of mercury with nitrogen-containing chelating ligands

Abstract

Intramolecularly stabilized divalent mercury selenolates of empirical formula Hg(SeR)₂[R=2-Me₂NCH₂C₆H₄1, (S)-2-Me₂NCHMeC₆H₄2, (R,S)-(C₅H₅)Fe(2-Me₂NCHMeC₅H₃)3 and (S,R)-(C₅H₅)Fe(2-Me₂NCHMeC₅H₃)4] have been synthesized in high yield by treating the corresponding diselenides with elemental mercury. The compounds show excellent solubility in non-polar solvents. They were characterized by elemental analysis, ¹H, ¹³C, ⁷⁷Se NMR, IR, Fourier-transform Raman and mass spectral techniques. The single-crystal structures of 1 and 4 were determined. Both are monomeric and the Hg atom is four-co-ordinate, being bound to a pair of chelating aminoselenolate ligands with both the six-membered rings having Se-Hg-N co-ordination adopting an envelope conformation. The bond configuration about Hg in 1 can be approximated to distorted tetrahedral, while in 4 it is more square planar with the two Se atoms being mutually trans and the Se-Hg-Se angle 168.6(2)°. Compounds 1 and 2 vaporize without decomposition at atmospheric pressure and decompose at higher temperatures to give HgSe while 3 decomposes to HgSe.