Abstract

A series of new layered gallium(III) and indium(III) phosphonates, phenylarsonates and phenylphosphinates have been prepared and characterised. The methylphosphonate, phenylphosphonate and phenylarsonate derivatives of gallium(III) possess a metal to ligand ratio of 1 ∶ 1 and properties consistent with the formulation Ga(OH)(O₃XR) (where X = P or As for R = C₆H₅, and where X = P for R = CH₃), whereas the benzylphosphonate derivative forms the monohydrate Ga(OH)(O₃XCH₂C₆H₅)·H₂O. The corresponding phosphinate derivative of gallium(III) has a metal to ligand ratio of 1 ∶ 2 with the formulation Ga(OH)(O₂P(H)C₆H₅)₂. The gallium compounds all contain a hydroxo group bonded to the metal, unlike the corresponding indium(III) compounds. The phenylphosphonate and phenylarsonate derivatives of indium(III) have a 1 ∶ 2 metal to ligand ratio and formula In(O₃XR)(O₂X(OH)R)·H₂O (where R = C₆H₅ or CH₂C₆H₅ when X = P and R = C₆H₅ when X = As), where the ligand is present as both a mono- and di-anion. The methylphosphonate of indium(III) has the unexpected formulation In₂(O₃PCH₃)₃·2H₂O whereas the indium(III) phenylphosphinate compound is In(O₂P(H)C₆H₅)₃. These compounds were characterized by elemental analysis, thermal gravimetry, X-ray powder diffraction (XRD) and solid state ³¹P/¹³C MAS NMR spectroscopy. Powder XRD measurements indicate these compounds contain layered solid state structures.