Synthesis and characterization of metal carboxyalkylphosphonates hybrid materials

Several carboxyalkylphosphonate hybrid materials have been prepared under hydrothermal conditions: Mn-2(OH)(O3PCH2CO2).1/2H(2)O, Mn-2(OH)(O3PCH2CO2), Al-3(OH)(3)(O3PCH2CH2CO2)(2).3H(2)O, Pb-5(O3PCH2CH2CO2)(2)(O3PCH2CH2COOH)(2) and Pb-3(O3PCH2CH2CO2)(2). The influence of some variables in the syntheses such as pH or metal/phosphonic acid molar ratios have been examined. Mn-2(OH)(O3PCH2CO2).1/2H(2)O crystallizes in a triclinic cell with parameters a = 8.405 Angstrom, b = 8.789 Angstrom, c = 4.910 Angstrom, alpha = 90.71degrees, beta = 98.58degrees, gamma = 103.68degrees and V = 348.6 Angstrom(3). Its dehydration lead to Mn-2(OH)(O3PCH2CO2), which unit cell has also been determined: a = 8.307 Angstrom, b = 8.322 Angstrom, c = 4.940 Angstrom, alpha = 103.31degrees, beta = 98.81degrees, gamma = 80.79degrees and V = 325.6 Angstrom(3). The diffraction data suggest a layered structure. Al-3(OH)(3)(O3PCH2CH2CO2)(2.)3H(2)O crystallizes in a monoclinic unit cell with a = 10.534 Angstrom, b = 7.880 Angstrom, c = 10.320 Angstrom, beta = 109.86degrees and V = 805.7 Angstrom(3). Its X-ray powder pattern and the spectroscopic data are consistent with a pillared layered structure. Finally, Pb-5(O3PCH2CH2CO2)(2)(O3PCH2CH2COOH)(2) is monoclinic with a = 11.889(1) Angstrom, b = 12.746(1) Angstrom, c = 9.835(1) Angstrom, beta = 114.081(2)degrees, V = 1360.6(2) Angstrom(3), Z = 2, space group P2(1)/c. Its structure has been solved from single crystal data, R-1 = 0.069, and shows a pillared layered framework. There are two types of carboxyethylphosphonate chains, one being protonated which is pillaring the layers and the other chain is twisted and bonded to a unique inorganic layer through both carboxylate and phosphonate moieties. Thermal and IR data for these compounds are reported and discussed.