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

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((mu)-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((mu)-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((mu)-X)2L2] with the syn arrangement of the phosphorus donor ligands L.