Synthesis, characterization, and structures of zinc(II) and cadmium(II) complexes with phosphoramides bearing cyclic amino groups

Abstract

Twelve new zinc(II) and cadmium(II) complexes with symmetric ligands, [MCl₂((R₂N)₃PO)₂] (M = Zn, R₂N = pyrrolidinyl (1), piperidinyl (2); M = Cd, R₂N = pyrrolidinyl (3), piperidinyl (4)), and differently substituted ligands of the general formula [MCl₂(R₂N)PO(R’₂N)₂] (M = Zn or Cd; R₂N = Pyrr, Pip or Mor; R’₂N = Pyrr, Pip or Mor (5–12) have been synthesized from reaction of zinc(II) or cadmium(II) chlorides with the ligands, giving yields of 43–76%. The complexes were characterized with multinuclear (¹H, ¹³C and ³¹P) NMR, conductivity, IR spectroscopy, and X-ray analyses. Complexes 1, 3, 11, and 12 are comprised of two ligands coordinated to the metal center in a distorted monomeric tetrahedral arrangement. The P = O bond lengths of 1.490(3) (1), 1.497(4) (3), 1.480(4) (11), and 1.479(5) Å (12) are in the order observed for analogous phosphoramide complexes. The results are compared with those reported for related chalcogen counterparts.

Graphical Abstract

Keywords:

• Phosphoramides
• zinc(II)
• cadmium(II)
• metal complex
• NMR
• X-ray analysis

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 financial support (LR99ES14), to the French Service for Cooperation and Cultural Action and Agence Universitaire de la Francophonie (AUF) in Nouakchott, Mauritania for a scholarship to MM.