Studies on Magnetic and Dielectric Properties of Antiferromagnetically Coupled Dinuclear Cu(II) in a One-Dimensional Cu(II) Coordination Polymer.

A one-dimensional Cu(II) coordination polymer with encapsulated antiferromagnetically coupled binuclear Cu(II) has been synthesized by using 5-nitroisophthalic acid (5-N-IPA) and 4-aminopyridine (4-APY) [Cu2(5-N-IPA)2(4-APY)4] n (1). Electrical properties are examined by complex impedance (Z*), dielectric permittivity (ε*), and ac conductivity studies at different frequencies (10 kHz-5 MHz) and temperatures (253-333 K). The contribution of grain and grain boundary has been explained by a different theoretical model. The variable temperature magnetic susceptibility data for compound 1 were recorded between 300 and 2 K. The shape of the curve (χM T vs T) indicates dominant antiferromagnetic coupling, which results from the interaction between the copper(II) atoms.

Three-Dimensional-Coordination Polymer of Zn(II)-Carboxylate: Structural Elucidation, Photoelectrical Conductivity, and Biological Activity.

A newly designed mixed-ligand coordination polymer [Zn4(bdc)4(ppmh)2(H2O)] n (1) (H2 bdc = 1,4-benzene dicarboxylic acid, ppmh = N-pyridin-2-yl-N'-pyridin-4-ylmethylene-hydrazine) has been characterized using different physicochemical techniques. The structure has been confirmed by single crystal X-ray diffraction measurements. There are two pyridyl-N and one hydrazino-imine-N donor centers in ppmh, where two pyridyl-Ns bind simultaneously to two Zn(II) to serve as a bridging agent to form a coordination polymer. The 1,4-benzene dicarboxylato (bdc) is ligated via the aromatic dicarboxylato-O to form a one-dimensional (1D) chain. These two 1D chains about Zn(II) constitute a two-dimensional structure, which undergoes noncovalent interactions (C-H···π and π···π) to generate a three-dimensional supramolecular assembly. Electrical conductivity of 1 is higher by 1 order (1.37 × 10-6 S/cm) than that of the free ligand, ppmh (6.2 × 10-7 S/cm). Especially, the responsivity of the compound 1 was 56.21 mA/W, which is 11 times higher than that of the ligand ppmh (5.12 mA/W). The specific detectivity of the compound was 2.17 × 1010 Jones, which is also almost 10 times higher with respect to the specific detectivity of the ligand-based device (4.53 × 109 Jones). The results show that the compound can be valuable for optoelectronic fields. The biological studies suggest that compound 1 is antibacterial as well as a promising anticancer agent (LD50, 42.2 µg/mL against HepG2 cells), while ligands remain silent. Investigation of the mechanism of the cell killing activity of compound 1 accounts the generation of intracellular reactive oxygen species.