Mixed-solvothermal syntheses, structures and luminescence properties of two new Zn(II) phosphonates with layered and 3D framework structures

Two new zinc phosphonates with 2-hydroxyphosphonoacetic acid (HPAA) and 1-hydroxyethylidenediphosphonic acid (hedpH(4)), [Zn-2{HO3PCH(OH)CO2}(3)]center dot 2NH(2)(CH3)(2)center dot 3H(2)O (1) and [Zn-3{CH3C(OH) (PO3)(2)}(2)]center dot 2NH(2)(CH3)(2)center dot H2O (2) have been synthesized under mixed-solvothermal conditions at 160 degrees C and structurally characterized by X-ray single-crystal diffraction, X-ray powder diffraction, infrared spectroscopy and elemental analysis. The structure of compound 1 comprises Zn1O(6) and Zn2O6 octahedra connected by [HO3PCH(OH)CO2](2) to form a 2D layered structure with one-dimensional channel system along c-axis direction, and the protonated dimethylamine cations are being located between two adjacent layers. Interestingly the layers of 1 arranged in an alternative sequence (ABAB). Compound 2 features a 3D framework structure with channels along the b- and c-axis, respectively. The charge-compensating protonated Hdma(+) cations and solvate water molecules are located inside the channels along the c-axis. A notable feature for compound 2 is the presence of the alternate left-and right-handed helical chains in the structure. The luminescence properties of compounds 1 and 2 have also been studied. (C) 2011 Elsevier B.V. All rights reserved.