Synthesis and structure of the phosphonocarboxylic acid H2O3PCH2-NC5H9-COOH center dot 2H2O and the manganese phosphonocarboxylate Mn[O3PCH2-N(H)C(5)H9-COO]

The phosphonocarboxylic acid H2O3PCH2-NC5H9-COOH(.)2H(2)O (1) was synthesized by a Mannich-type reaction. Recrystallization from hydrochloric acid yields large single crystals (crystal data 1: monoclinic, P2(1)/n, a = 6.4011(3), b = 25.633(2), c = 7.2496(4) Angstrom, beta = 95.473(7)degrees, V = 1184.1(2) Angstrom(3), Z = 4). In an aqueous solution two isomers of I were unambiguously detected by NMR-spectroscopy. The reaction of I with manganese chloride under hydrothermal conditions at pH 5 yields the new manganese phosphonocarboxylate Mn[O3PCH2-N(H)C5H9-COO] (2) that was characterized by single crystal X-ray diffraction (crystal data 2: monoclinic, P2(1)/a, a = 10.2784(2), b = 9.0649(2), c = 11.0712(2) Angstrom, beta = 107.280(1)degrees, V = 984.97(3) Angstrom(3), Z = 4). In I zwitter-ions HO3PCH2-N(H)C5H9-COOH and H2O molecules are interconnected by O-(HO)-O-... and N-(HO)-O-... hydrogen bonds to form a three-dimensional network. In 2, corner-linked MnO5 and PO3C polyhedra form four- and eight-rings which are connected to a two-dimensional net. The coordination of the carboxylate ions, which act as chelating ligands, leads to a pillared structure.