Synthesis and characterization of a novel layered zinc phosphate

摘要

The syntheses and crystal structures of a novel layered zinc phosphate and its high temperature variant are described. Both structures were solved from powder diffraction data using both synchrotron and conventional X-ray radiation. The as-synthesized material (UiO-27-as) with composition (C_6H_(17)N_3)~(2+) (Zn_3(HPO_4)(PO_4)_2)~(2-) centre dot H_2O crystallizes in the space group P2_1/c with a = 12.67072(15), h = 8.24293(8), C = 18.48425(l9) A, #beta# = 109.1346(7)o and V = 1823.904(35) A~3. The zinc phosphate layers are built from corner sharing hexameric secondary building units. In the interlamellar space there are organic cations and water molecules. A high temperature variant exists around 200 deg C (UiO-27-200). This compound (C_6H_(17)N_3)~(2+)(HZn_3(PO_4)_3)~(2-) crystallizes in the monoclinic space group P2_1/C with a = 12.29010(23), b = 8.39995(13), C= 18.49914(30) A, #beta# = 114.2504(11) deg and V = 1741.261(51) A~3. The transformation to UiO-27-200 involves removal of the interlamellar water molecules. The atomic arrangement within the zinc phosphate layers is maintained; however, the layers are brought closer which leads to inter-layer hydrogen bonding interactions.