Synthesis, structural characterization, and optical properties of two Co(II)-based coordination compounds

Two new Co(II)-based coordination compounds, [Co(Hmctrz)2(H2O)2] (1) and [Co(Hdctrz)(H2O)2]n (2), were synthesized via routine or hydrothermal reactions using cobalt salts, triazole derivatives, and auxiliary reagents. Characterizations, including single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, TGA, and PXRD, confirmed their formation. UV-Vis and fluorescence studies revealed distinct optical properties, with 1 and 2 exhibiting UV absorption peaks at 353 and 370 nm, respectively, and concentration-dependent fluorescence emission, indicating potential for optoelectronic and biological imaging applications. Additionally, adsorption studies showed excellent dye removal capabilities, with 1 achieving 98% removal of methylene blue (MB) and 93% of methyl orange (MO), outperforming 2, which removed 95% of MB and 87% of MO. These results highlight the compounds’ potential in both environmental remediation and advanced material applications.