Metal-organodiphosphonate chemistry: Hydrothermal syntheses and structures of Zn(II) and Cd(II) coordination polymers with xylyldiphosphonate ligands

•Hydrothermal syntheses of twelve novel Zn(II) and Cd(II)-diphosphonate materials.•Influence of ancillary ligands on structures of metal-diphosphonate materials.•Structural consequences of xylyldiphosphonate isomers on metal-diphosphonates.•Identification of recurring structural types and secondary building units.

Hydrothermal reactions of zinc(II) acetate dihydrate or cadmium(II) nitrate tetrahydrate with xylyldiphosphonic acid isomers in the presence of an organonitrogen chelating ancillary ligand provided a series of materials of the (M(II)-organonitrogen chelate)/xylyldiphosphonate family. One-dimensional structures were observed for [Zn(H2O)(bpy)(1,2-HO3PC8H8PO3H)] (1), [Zn(bpy)(1,3-HO3PC8H8PO3H)]·H2O (2·H2O), [M(o-phen)(1,3-HO3PC8H8PO3H)] (M = Zn (5·H2O), M = Cd (11), and [Zn(tpyprz)(1,2-HO3PC8H8PO3H)] (7), while the phases [M(bpy)2(1,4-H2O3PC8H8PO3H2)(1,4-HO3PC8H8PO3H)] (M = Zn (3) and Cd(9)) exhibited virtual layered structures constructed from {M(bpy)2(1,4-H2O3PC8H8PO3H2)}n2n+ chain hydrogen-bonded to the {HO3PC8H8PO3H}2- charge compensating anions. The two-dimensional structures are represented by [M(o-phen)(1,2-HO3PC8H8PO3H)] (M = Zn (4) and Cd (10)) and [Cd(bpy)(1,3-HO3PC8H8PO3H)] (8). Expansion into three-dimensions occurs only with the spatially extended 1,4-xylyldiphosphonate ligand in [Zn4(o-phen)4(1,4-HO3PC8H8PO3)2(1,4-HO3PC8H8PO3H)]·3H2O (6·3H2O) and [Cd(o-phen)(1,4-HO3PC8H8PO3H)] (12).

Graphical abstractHydrothermal reaction conditions were used to prepare a series of materials of the M(II)-imine/xylyldiphosphonate family where M is Zn(II) or Cd(II). The structural chemistry and the luminescence properties of the materials are discussed. The structure of the three dimensional material [Zn4(o-phen)4(1,4-HO3PC8H8PO3)2(1,4-HO3PC8H8PO3H)]3·H2O (6·3H2O) is illustrated.Figure optionsDownload full-size imageDownload as PowerPoint slide