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

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.