Hydrothermal synthesis of (C5H14N2)[CoCl4]⸳0.5H2O: Crystal structure, spectroscopic characterization, thermal behavior, magnetic properties and biological evaluation

The organic-inorganic compound (C5H14N2)[CoCl4]center dot 0.5H(2)O, I, was characterized by various physicochemical techniques. The X-ray diffraction analysis revealed that the compound crystallizes in the centrosymmetric space group C2/c of the monoclinic system. The atomic arrangement the Co(II) complex is built from isolated [CoCl4](2-) Anions, 1-methylpiperazine-1,4-diium [C5H14N2](2+) cations and free water molecules. The crystal structure study showed that the cohesion of I is assured through N-H center dot center dot center dot Cl and N-H center dot center dot center dot O hydrogen bonds giving birth to a 3-D architecture. Hirshfeld surface analysis revealed that Cl center dot center dot center dot H/H center dot center dot center dot Cl and H center dot center dot center dot H (58.5 and 36.4%, respectively) are the most significant interactions between species. Minor O center dot center dot center dot H/H center dot center dot center dot O interactions are also present. The compound was characterized by thermal analysis, TGA-DTA showed the removal of the co-crystallized water before 100 degrees C and a first mass loss at around 120 degrees C. Magnetic measurements are in good agreement with isolated, S = 3/2, tetrahedral [CoCl4](2-) anions. The negative Weiss constant of -1.35 indicates single-ion anisotropy and very weak antiferromagnetic interactions. UV-visible spectroscopy reveals three weak absorp tion bands in the visible range due to the d-d electronic transitions typical of the Co(II) tetra-coordinated. A bioassay showed antibacterial activity against the gram negative Klebsiella pneumonia and gram positive Bacillus ceureus, Listeria monocytogenes, and Micrococcus lutues.