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.