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

• Hydrothermal syntheses of Cu(II)-imine/VxOyFz/xylyldiphosphonate compounds.
• Structural influence of the positional isomers of the xylyldiphosphonate ligand.
• Structural comparisons to previously reported classes of oxyfluorovanadates.
• Identification of recurring structural types and secondary building units.

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.

Hydrothermal synthesis provides two novel materials of the Cu(II)-imine/VxOy/xylyldiphosphonate family and six oxyfluorovanadates of the Cu(II)-imine/VxOyFz/xylyldiphosphonate class. The 2D structure of [Cu2(dpa)2V2F2O4(1,3-xylyldiphos)] is shown.Figure optionsDownload as PowerPoint slide