Structural consequences of fluoride incorporation into oxovanadium-xylyldiphosphonates with charge compensating copper(II)-imine components

The hydrothermal reactions of V2O5, Cu(CH3CO2)2·H2O, an appropriate imine, a xylyl-diphosphonic acid and HF in low HF/V ratio yielded the bimetallic xylyldiphosphonate phases, [Cu(o-phen)VO2(1,2-HO3PC8H8PO3)] (1) and [Cu2(dpa)2V2O5(1,3-O3PC8H8PO3)] (2). When the HF/V ratio was increased to ca. 23:1, a series of materials of the VxFyOz/copper-imine/xylyldiphosphonate family were prepared. These include the one-dimensional [Cu2(o-phen)2V2F2O4(H2O)(1,3-O3PC8H8PO3)] (3), the two-dimensional [Cu2(o-phen)2V2F2O4(1,4-O3PC8H8PO3)] (4), [Cu2(dpa)2V2F2O4(1,2-O3PC8H8PO3)] (5) and [Cu2(dpa)2V2F2O4(1,3-O3PC8H8PO3)] (6·H2O), and the three-dimensional [Cu2(bpy)2V2F2O4(1,4-O3PC8H8PO3)] (7) and [{Cu2(tpyprz)(H2O)2}V2F2O4(1,3-O3PC8H8PO3)] (8·2H2O). The influences of structural determinants such as the xylyldiphosphonate geometry, the identity of the imine coligand and fluoride substitution for oxide are discussed.