Disubstituted diphenyldithiophosphates of cadmium: synthesis, characterization, and single-crystal X-ray structure

Abstract

A series of new disubstituted diphenyldithiophosphate complexes of cadmium [{(ArO)2PS2}2Cd] (9–12) have been isolated in aqueous media while their donor stabilized adducts [{(ArO)2PS2}2Cd·2C5H5N] (13–16) [(Ar = 2,4-(CH3)2C6H3, 2,5-(CH3)2C6H3, 3,4-(CH3)2C6H3 and 3,5-(CH3)2C6H3)] have been isolated in chloroform. These newly synthesized complexes were characterized by elemental analyses, IR and NMR (1H, 13C and 31P) spectroscopic analyses. The dithiophosphate ligands are coordinated bidentate to the cadmium ion via the two thiolate sulfurs. The compounds [{(3,5-CH3)2C6H3O}2PS2HNEt3] (4) and [{(3,5-CH3)2C6H3O}2PS2]2Cd(NC5H5)2 (16) crystallize in the monoclinic system with space group P21/c. Single-crystal X-ray analysis of 4 reveals that phosphorus of the anion is tetrahedrally bonded to two S and two O atoms. The structure is stabilized by cation–anion N–H⋯S intermolecular hydrogen bond interactions. In 16, two diphenyldithiophosphate ions are bidentate with both sulfurs coordinated to cadmium. Each forms a four-membered chelate ring in the equatorial plane. Two pyridines are axially coordinated to cadmium leading to octahedral geometry. The thermal properties of this complex have also been examined by combined DTA/DTG thermal analyses.