Two 3-D Cluster-Based Frameworks: Highly Eight-Connected Molecular Topology and Magnetism

Abstract

A couple of metal-organic frameworks (MOFs) constructed from rigid bicarboxylates are presented herein, namely, Co3(ndc)3(bbi)(CH3CN)2 (1) and Dy2Mn3(ndc)6(bipy)2 (2), where H2ndc = 2,6-naphthalenedicarboxylic acid, bipy = 2,2′-pyridine, and bbi = 1,1′-(1,4-butanediyl)bis(imidazole). These two coordination polymers have been prepared through solvo/hydrothermal reactions and characterized by single-crystal X-ray study, TG, IR, and elemental analysis. Polymer 1 features a novel self-penetrating network mediated by flexible long-chain ligand and well defines a unique 416·58·64 topology with the treatment of Co3 unit as an 8-connected node, which equals the highest connectivity for monometallic self-penetrating system so far. Polymer 2 represents the first example of a MnII−DyIII (3d-4f) heteropentanuclear complex showing an intriguing 3-D 36·418·53·6 framework upon the assignment of Dy2Mn3 cluster to an 8-connected node. In addition, magnetic studies of 1 reveal that the antiferromagnetic behavior is operative within the trimeric Co3 cluster and 2 demonstrates dominant ferromagnetic coupling interactions between DyIII and MnII ions.