Rheological phase synthesis and characterization of a series of metal diphosphonate compounds

Three new transition metal diphosphonate compounds have been successfully obtained by a rheological phase reaction method at 80 °C, namely Co(phen)(AEDPH3)2·4H2O (1), Cu(2,2′-bipy)(H2O)(HEDPH2)·2H2O (2), and Cu(phen)(H2O)(HEDPH2)·2H2O (3) (AEDPH4 = 1-aminoethylidenediphosphonic acid, HEDPH4 = 1-hydroxyethylidenediphosphonic acid, phen = 1,10-phenanhroline, 2,2′-bipy = 2,2′-bipyridine). All compounds were structurally characterized by single-crystal diffraction method, EA, IR and TG analysis. In all cases, the compounds illustrate 3D supramolecular structure linked by hydrogen bonds and strong aromatic-aromatic interactions. The further magnetic study shows compound 1 exhibits weak antiferromagnetic interaction via the hydrogen bond and strong π-π stacking interactions.