Synthesis and Crystal Structural Characterization of Mixed-Ligand Cadmium(II) Complexes of 3-Triphenylphosphoniopropanoate and N ,N ,N′ ,N′-Tetramethylethylenediamine (tmen)

Abstract

Two mixed-ligand cadmium(II) complexes have been synthesized from the reaction of 3-triphenyl- phosphoniopropanoate, Ph₃P⁺ (CH₂)₂CO₂¯, and Me₂N(CH₂)₂NMe₂ (abbreviated as tmen) with Cd(ClO₄)₂.x H₂O and CdI₂, and structurally characterized by single-crystal X-ray analysis: [Cd { Ph₃P(CH₂)₂CO₂ } ₂(tmen)(H₂O)] (ClO₄)₂.2H₂O (1), space group P ^-1 with a 13·461(5), b 13·694(5), c 18·229(4) Å, α 92·34(2), β 110·51(2), γ 117·44(2)° and Z 2; [CdI₂ { Ph₃P(CH₂)₂CO₂ } (tmen)] (2), space group P 2₁/c with a 16·768(6), b 11·741(3), c 16·915(5) Å, β 112·28(2)° and Z 4. In complex (1), the cadmium(II) atom is in a distorted pentagonal bipyramidal environment with two chelated betaine ligands and one nitrogen atom of the chelated tmen ligand defining the equatorial plane, and an aqua ligand and the other tmen nitrogen atom occupying the axial positions. One of the betaine ligands acts in the symmetric and the other in the asymmetric chelate mode. In complex (2), the distorted octahedral coordination environment about the cadmium(II) atom involves a chelated tmen ligand, an asymmetrically chelated betaine ligand, and two cis-related iodo ligands.