Cu II 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 II 4 ] 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 [Cu{py 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 II 4 ] units dominated by antiferromagnetic interactions.