The synthesis and X-ray structure of five co-ordinate imidodiphosphinate complexes of indium(III)

We report the synthesis and structural characterisation of three five co-ordinate indium(III) bis-chelate complexes of imidodiphosphinates with general formula InCl{N(PR₂X)₂}₂, (R=Ph or Prⁱ, X=S or Se), formed from the 1:2 reaction of indium(III) trichloride and the potassium or sodium salt of the ligand in methanol/THF. The complexes consist of discrete monomeric, molecules and show a trigonal–bipyramidal co-ordination pattern. These are the first examples of five co-ordinate complexes containing this type of ligand, in contrast to other indium(III) and main group element complexes of similar ligands in which only the six co-ordinate tris-chelates are known.