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 ¹H and ³¹P NMR, IR, elemental analysis, conductivity, and single crystal X-ray diffraction analysis. The results show that the complexes are pseudo-tetrahedral containing coordinated chloride ions. Interestingly, the X-ray studies reveal that while the title ligands produce dinuclear complexes with Hg, their Cd and Zn complexes are mononuclear. The tetrahedral bond angles vary from 85.69(5)° to 126.25(4)° in dinuclear complexes 5 and 6 and from 93.51(3)° to 117.38(3)° in mononuclear species 2-4. The E = S 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.

Graphical Abstract

Keywords:

• Phosphine chalcogenides
• pyrrolidine
• metal complexes
• NMR spectroscopy

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We are grateful to the Tunisian Ministry of High Education and Scientific Research for support [grant number: LR99ES14] and to the French Service for Cooperation and Cultural Action (SCAC) in Nouakchott, Mauritania for a scholarship to KE.