Simple and Mixed Ligand Complexes of Ag(I) Involving Substituted Dithiocarbamic Acids, Triphenylphosphine and the Chelating Phosphine Diphos-A Synthetic and Spectrophotometric Study

Abstract

Silver(I), being a soft acid shows a preference for P and S containing ligands. In the present study, simple and mixed ligand complexes of Ag(I) involving mono-and diethanoldithiocarbamates, Ag(MEADTC) and Ag(DEADTC), with triphenylphosphine and 1,2-bis(diphenylphosphino)ethane (diphos) were synthesized. For a comparison, Ag(DEDTC), the diethyl analogue, was also synthesized and the properties studied with IR, UV-visible, TG, DT techniques. The mixed ligand complexes involving PPh₃ and diphos viz., Ag(DEDTC)(PPh₃)₂, Ag(DEDTC)(diphos), Ag(DEADTC)(PPh₃)₂ and Ag(DEADTC)(diphos) (DEDTC⁻ = diethyldithiocarbamate anion, DEADTC⁻ = diethanoldithiocarbamate anion) showed very low conductivity indicating non-ionic character and ruled out possible ion pair formation such as [(PPh₃)₂Ag]⁺DEDTC⁻ or [(diphos)Ag]⁺DEDTC⁻ proposed earlier. In addition, the isolated Ag(MEADTC) complex was found to be highly unstable and, hence, an equilibrium study was made and the stability constant was determined to be 6.1 ± 0.2 by the Harvey and Manning method.