Triazole-bridged magnetic M(II) assemblies (M = Co, Ni) capped with the end-on terephthalate dianion involving multi-intermolecular contacts

Two dimeric complexes [M₂(atrz)₃(H₂O)₄(tp)₂] · 11H₂O [M = Co(1 · 11H₂O), Ni(2 · 11H₂O); tp = terephthalate, atrz = 4-aminotriazole] were constructed from triply-bridged triazole ligands and terminal tp groups. Interestingly tp behaves as a capping group in an end-on fashion, which is a rare example for tp-related systems. Among the dinuclear assemblies, three types of intermolecular interactions (hydrogen bond, face-to-face π-π and edge-to-face CH-π contacts) as well as intramolecular hydrogen bonding are observed, eventually leading to the formation of a 3D network. Magnetic data show that moderate antiferromagnetic interactions between the two metal centers communicate through triazole groups, and non-negligible interdimer antiferromagnetic couplings are also involved in this system.