A bibliographic survey of the structural chemistry of the Group 13 dithiophosphates and dithiophosphinates

A survey of the crystallographically determined structures of the Group 13 dithiophosphates and dithiophosphinates is presented with a focus upon both the molecular structures and supramolecular association involving the heavy element. Only small numbers of aluminium(III) (two) and gallium(III) (one) structures are known and these along with the 10 indium(III) examples have a preponderance towards homoleptic species with most coordination geometries based on an octahedron owing to the presence of symmetrically or almost symmetrically chelating phosphorodithiolato ligands; the notable exception is the gallium species which has an approximately tetrahedral geometry as two of the dithiophosphinate ligands coordinate in a monodentate mode. Diverse molecular structures are noted for the four heteroleptic examples of the lighter Group 13 elements which assemble in their crystals employing intermolecular interactions that do not involve the central element, as with the homoleptic structures. A completely different situation is evident for the thallium(I)/(III) structures which display a diverse array of coordination geometries and which usually assemble via Tl⋯S triel-bonding interactions; in the supramolecular assembly of thallium(I) crystals, Tl(lone-pair)⋯π(aryl) interactions are often observed.