Synthesis of bis(2-pyridylmethyl)selenide and solid-state structural characterization of bis-tridentate zinc triad perchlorate chelates

Bis-tridentate chelates of Cd(ClO4)2 and Hg(ClO4)2 with N4Se2 metal coordination environments were isolated by slow evaporation from methanol/n-butanol solutions containing two equivalents of bis(2-methylpyridyl)selenide (L). The ligand L was obtained through a previously unexplored pathway to symmetric selenoethers involving selenoacetamide. Although no structurally characterized complexes of the harder group 12 metal ions Zn(II) or Cd(II) with selenoether ligands have had M–SeR2 bonds and numerous attempts to crystallize a bis-tridentate chelate of Zn(II) were unsuccessful, the distorted trans facial octahedral complex [CdL2](ClO4)2 was characterized. In addition, X-ray crystallographic characterization of [HgL2](ClO4)2 revealed a mononuclear structure with distorted trigonal prismatic coordination geometry, the highest coordination number Hg(II) complex with selenoether ligands yet reported.

The bis-tridentate chelates obtained from the first metal coordination studies of bis(2-methylpyridyl)selenide provided the first structurally characterized complex with a Cd–SeR2 bond and the highest coordination number Hg(II) complex of a selenoether ligand yet reported.Figure optionsDownload as PowerPoint slide