Synthetic pathway to new vanadyl carboxyphosphonates

In a previous work, we showed that intercalated vanadyl phosphonates were obtained from phosphonic acid HOOCCH2PO3H in alcoholic medium, whereas no intercalation occurred when carboxyethylphosphonic acid HOOC(CH2)2PO3H2 was used in the same medium, because the carboxylic acid functions were partially esterified in the interlamellar domain. The present work deals with the synthesis of new functionalized vanadyl phosphonates by choosing the appropriate precursors. These materials, the general formula of which is VORPO3·nH2O, were prepared from phosphonic acids where R consisted of a reactive ending −COOH and an alkyl chain such as in HOOC(CH2)nPO3H2 (n = 1, 2, 3) or a ramified chain such as in HOOCCH(CH3)PO3H2 and HOOCCH(C2H5)PO3H2. Different synthesis methods were used depending on the organic component of the phosphonic acid used.