Transition metal dithiophosphate complex
Transition metal dithiophosphate complexes are coordination compounds containing dithiophosphate ligands, i.e. ligands of the formula 2PS. The charge-neutral complexes tend to be soluble in organic solvents, especially when R is branched. Dithiophosphates are available with a wide variety of alkoxy groups. The range of complexes is similar to those for dithiocarbamate complexes.
Preparation
Dithiophosphate ligands are prepared by alcoholysis of phosphorus pentasulfide:Dialkoxydithiophoric acids react with many metal oxides, chlorides, and acetates:
Alternatively, salts, such as ammonium diethyldithiophosphate, can be used to prepare complexes by salt metathesis reactions:
Oxidation of dithiophosphoric acid gives the disulfide. Dithiophosphate complexes have also be prepared by oxidative addition of these disulfides:
Ligand properties
Dithiophosphates, when bidentate, are classified as L-X ligands in the Covalent bond classification method. In the usual electron counting method, they are three-electron ligands. With respect to HSAB theory, dithiophosphates are classified as soft ligands. In addition to the conventional representation, they are also described by a zwitterionic resonance structure. Phosphorus is tetrahedral.Selected homoleptic complexes
Homoleptic complexes have formulas,, and M2.- 3, red-brown,
- , violet
- , red
- pink, paramagnetic
- violet
- yellow, diamagnetic
- poly-