Tetraphosphinitoresorcinarene complexes: a new structural form for diphosphine mercury(ii) halide complexes

Abstract

Mercury(II) halide derivatives of tetrakis(diphenylphosphinite) ligands derived from a resorcinarene have been characterized, in both the solid and solution states. The complexes have the general formula [Resorcinarene(O₂CR)₄(OPPh₂HgX₂)₄], with Resorcinarene = (PhCH₂CH₂CHC₆H₂)₄; R = OCH₂Ph, C₆H₁₁, 4-C₆H₄Me, OCH₂CCH; X = Cl, Br, I, and each contains two Hg₂X₂(μ-X)₂(PP) units, in which PP represents a bis(diphenylphosphinite) group of the ligand. This is a new structural form for the much-studied mercury(II) halide complexes with phosphine ligands and it arises since the resorcinarene-derived ligands act as if they contain two separate diphosphinite bidentate ligands, each having a long bite distance that can span the Hg₂(μ-X)₂ unit. In particular, this work provides the first structural characterization of mercury(II) halide diphosphine complexes with 1 ∶ 1 Hg ∶ P stoichiometry, and the first examples of complexes [Hg₂X₂(μ-X)₂L₂] with the syn arrangement of the phosphorus donor ligands L.