Hydrothermal synthesis and crystal structure of Zn4(PO4)2(HPO4)2•0.5(C10H28N4)•2H2O, a new layered zinc phosphate with 12-ring cavities

Using 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) as a template, a new layered zinc phosphate Zn-4(PO4)(2)(HPO4)(2).0.5(C10H28N4). 2H(2)O (defined as ZnPO-cyclam) with 12-ring cavities was synthesized under hydrothermal conditions in a molar ratio ZnO:P2O5:cyclam:H2O = 1:2.2:0.5:284.7 at 140 degreesC for 3 days. The gel had a pH 4 at the starting period. The ZnPO-cyclam crystal structure is solved using single-crystal X-ray diffraction data at 293 K. It crystallizes in monoclinic space group P2(1)/c (no.14) with lattice parameters a 15.758(3) Angstrom, b = 9.0292(15) Angstrom, c = 15.543(3) Angstrom, beta = 111.070 (16). V = 2063.7(7) Angstrom (3), Z = 4, R = 0.0392, wR = 0.0472, 4166 collected reflections, 2794 observed reflections with I > 2 sigma (I). The structure of ZnPO-cyclam consists of alternating inorganic and organic layers. The inorganic layers are built up from ZnO4, ZnO3(H2O)(2), PO4, and HPO4 with Zn-O-Zn and Zn-O-P bonds. The protonated cyclam molecules in which the four nitrogen atoms are all protonated form the organic layers. Strong hydrogen bonding exists between the inorganic-organic layers, and there are 12-ring cavities in the inorganic layers, in which the template cyclam molecules reside, (C) 2000 Academic Press.