Structural Diversity, Luminescence, and Magnetic Property: Series of Coordination Polymers with 2,2′-Bipyridyl-4,4′-Dicarboxylic Acid

Abstract

Eight coordination polymers associated with the organic ligand 2,2′-bipyridyl-4,4′-dicarboxylic acid (abbreviated H2BPDC): {[Zn(BPDC)(H2O)3]·3H2O}n (1), [Zn(BPDC)(H2O)2]n (2), [Co(BPDC)(H2O)3]n (3), [Co(BPDC)(H2O)2]n (3a), [Cu(BPDC)(H2O)]n (4), {[Cu(BPDC)(H2O)2]·2H2O}n (4a), [Mn(BPDC)(H2O)2]n (5), and {[Mn(BPDC)]·2H2O}n (5a) were prepared by hydrothermal methods and structurally characterized. The structure analyses reveal that 1 exhibits a one-dimension chain, and 2, 3a, 5, and 5a are complicated 3D structures. 2 displays a 2-fold interpenetrating chiral 3D framework with the rare (12,3) topology and 5 is a chiral 3D framework. 4 and 4a are two-dimensional networks, and 3 is a chiral 1D chain. The structural contrasts between 1 and 2, 3 and 3a, 4 and 4a, and 5 and 5a display the transformations from low to high dimensional motif, and/or from achiral to chiral structures. Interestingly, the large structure divergences mainly originated from the different reaction temperature (It should be noted that 3a, 4a, and 5a were also obtained independently by us, although they had been reported. Herein, they were only used to discuss the structural comparison investigations). The luminescent properties of 1 and 2 have been explored and compared with that of the ligand. The Cotton effect in solid circular dichroism (CD) spectra of 2 was significantly observed, indicative of the chirality of 2. Magnetic properties analyses for 3 and 5 were performed.