Interaction of mercury(II) halides with tertiary phosphine betaines: synthesis and structural characterization of [HgX2{Ph3P(CH2)2CO2}] (X=Cl, I) and [HgCl(μ-Cl)-{Ph3P(CH2)3CO2}

Abstract

Three new mercury(II) complexes containing tertiary phosphine betaine ligands Ph3P+(CH2)2CO2 − and Ph3P+(CH2)3CO2 − have been synthesized and fully characterized by single-crystal X-ray analysis: [HgCl2{Ph3(CH2)2CO2}],1, space groupP21/n,a=9.819(2),b=14.966(4),c=14.973(5) A, β=105.67(2)° andZ=4; [HgI2{Ph3(CH2)2CO2}],2,P21/n,a=10.206(2),b=14.807(3),c=15.557(3) A, β=107.11(2)° andZ=4; [HgCl(μ-Cl){Ph3P(CH2)3CO2}]2,3, $$P\bar 1$$ ,a=10.813(2),b=11.975(3),c=11.180(2) A, α=87.04(2), β=75.14(1), γ=81.95(1)° andZ=1. The isomorphous complexes1 and2 contain discrete mononuclear molecules in which the mercury(II) atom is unsymmetrically chelated by a Ph3P+(CH2)2CO 2 − ligand and coordinated by a pair of terminal halo ligands in a distorted tetrahedral environment, while3 consists of discrete centrosymmetric dinuclear molecules in which the betaine ligand Ph2P+(CH2)3CO 2 − acts in the chelate mode and the mercury(II) atoms are unsymmetrically bridged by a pair of chloro ligands.