Novel aluminium phenyl, benzyl, and bromobenzylphosphonates: structural characterisation and hydration-dehydration reactions

Reaction of phosphonic acids RPO(OH)(2) (R = phenyl, benzyl, 4-bromobenzyl) with aluminium nitrate and sulfate under various hydrothermal conditions l ed to three novel aluminium phosphonates, Al(OH)(O3PCH2C6H4Br). H2O, Al(OH) (O3PCH2C6H5). H2O and Al-2(O3PC6H5)(3). H2O. All the compounds were charact erised by powder XRD, elemental analysis, TGA, Al-27 and P-31 MAS NMR and I R spectroscopy. The same tools were used to study the dehydration-rehydrati on reactions. Refinement of the structure of Al(OH)(O3PCH2C6H4Br). H2O by t he Rietveld method showed a lamellar arrangement similar to the methyl anal ogue zeta-Al(OH)(O3PCH3). H2O. Al(OH)(O3PCH2C6H4Br). H2O crystallises in th e monoclinic system, space group P2(1)/c with unit cell parameters a = 16.4 972(2) Angstrom, b = 7.0673(1) Angstrom, c = 9.4950(2) Angstrom and beta = 113.477(1)degrees. Based on the powder XRD, IR and NMR data the two benzyl compounds were found to be isostructural.