Gallium(III) organophosphonate adducts with the bidentate amines 2,2'-bipyridyl and 1,10-phenanthroline

摘要

A number of gallium(III) organophosphonates form adducts with the bidentate amines 2,2'-bipyridyl and 1,10-phenanthroline Ga(O_3PR)(O_2P(ON)R)(C_10H_8N_2) centre dot H_2O and Ga(O_3PR)(O_2P(OH)R)(C_12H_8N_2) centre dot H_2O (where R = CH_3, C_6H_5 and CH_2C_6H_5C_10H_8N_2 is 2,2'-bipyridyl and C_12H_8N_2 is 1,10-phenanthroline). Unlike the parent gallium(III) organophosphonates, which conform to the general formula Ga(OH)(O_3PR) centre dot xH_2O (X = 0 OR 1), the amine adducts lack the hydroxo group, but contain the organophosphonate ligand in the partially as well as fully deprotonated forms. All compounds were isolated from aqueous solutions as monohydrates, with the exception of the bipyridyl adduct of gallium(III) phenylphosphonate, which is anhydrous. TGA measurements suggest that for the hydrates, the water molecule is not coordinated to the metal. The bipyridyl adducts of gallium(III) phenylphosphonate and gallium(III) methylphosphonate, like the parent gallium(III) organophosphonates, are very likely layered, as indicated by the powder XRD patterns. In contrast, the corresponding phenanthroline adducts are ono-layered, and both the bipyridyl and phenanthroline adducts of gallium(III) benzylphosphonate are amorphous solids. FTIR. powder XRD, TGA, XPS, solid state ~31P/~13C MAS-NMR and BET surface area data are presented and discussed.