CuII Frameworks from Di-2-pyridyl Ketone and Benzene-1,3,5-triphosphonic Acid

In our effort to develop new synthetic strategies for the isolation of new phosphonate frameworks, we exploited the possibility of simultaneously utilizing benzene-1,3,5-triphosphonic acid (H(6)btp) and di-2-pyridyl ketone (py(2)CO), which is a major player in the field of polynuclear metal complexes. This ligand blend in Cu-II chemistry afforded a 2D framework comprising tetranuclear [Cu-4(II)] secondary building units. A thorough investigation of the Cu-II/di-2-pyridyl ketone/benzene-1,3,5-triphosphonic acid reaction system also revealed a hydrogen-bonded framework. The structure of the latter comprises the cationic [Cupy(2)C(OH)(2)(2)](2+) complex [py(2)C(OH)(2) is the hydrate of py(2)CO], the dianion of benzene-1,3,5-triphosphonic acid (H(4)btp(2-)) and water solvates. The magnetic properties of the coordination polymer were rationalized on the basis of magnetically isolated [Cu-4(II)] units dominated by antiferromagnetic interactions.