Crystal structure, vibrational spectroscopic characterization, thermal behavior and antifungal activity of a novel coordination polymer of indole-3-carboxylic acid with cobalt(II) and a comparison with the isostructural Zn(II) complex

A new cobalt(II) coordination polymer of indole-3-carboxylic acid (I3CAH(2))(2)[Co(I3CAH)(2)(H2O)](n) has been synthesized and characterized using single-crystal X-ray diffraction, infrared spectroscopy and thermal (TGA/DTG analysis). The crystal structure is monoclinic, space group Cc, with a = 33406(7), b = 5.9287(12), c = 8.2790(17) angstrom, beta = 91,52(3)degrees V = 1639.1(6) angstrom(3) and Z = 4. Each cobalt cation is five-coordinated by the bidentate chelating indole-3-carboxylato ligand, one bridging oxygen atom from the other ligand in the same independent unit, one water molecule, and one bridging oxygen atom of the indole-3-carboxylato group from an adjacent [Co(I3CAH)(2)(H2O)] unit. Infrared spectra and TGA/DTG analysis of [Co(I3CAH)(2)(H2O)](n) in the solid state support the results from X-ray analysis. Comparison of the X-ray data and the vibrational spectra of the title compound with those of the previously reported zinc(II) coordination polymer [Co(I3CAH)(2)(H2O)](n) has shown that these compounds are isostructural. The antifungal activity of [Co(I3CAH)(2)(H2O)](n) against Aspergillus niger and Candida albicans has been investigated. The new Co(II) compound is remarkably effective against Candida albicans.