Synthesis and structural characterization of Zn²⁺, Cd²⁺ and Hg²⁺ complexes with tripyrrolidinophosphine chalcogenides

Abstract

Six new complexes of zinc(II), cadmium(II) and mercury(II) chlorides with tripyrrolidinophosphine chalcogenides of the types [MCl2(Pyrr3PE)2] (M = Zn, E = S (1) or E = Se (2); M = Cd, E = S (3) or E = Se (4)) and [{HgCl(Pyrr3PE)}2(µ-Cl)2] (E = S (5) or Se (6)) have been prepared in yields of 66-92% by reaction of the ligands with metal chloride in ethanol and characterized by 1 H and 31 P NMR, IR, elemental analysis, conductivity, and single crystal X-ray diffraction analysis. The results show that the complexes are pseudo tetrahedral containing coordinated chloride atoms. Interestingly, the X-ray studies reveal that whilst the title ligands produce dinuclear complexes with mercury, their Cd and Zn complexes are mononuclear. The tetrahedral bond angles vary from 85.69(5)° to 126.25(4)° in the dinuclear complexes 5 and 6 and from 93.51(3) o to 117.38(3) o in mononuclear species 2-4.The P=E bond lengths are in the range 1.999(9)-2.198(2) Å. The coordination properties of the title ligands are discussed and compared to those obtained for their bulkier counterparts.