Crystal structure, spectral characterization, photophysical properties, Hirshfeld surface analysis, and antimicrobial activity of homopiperazinium dichromate(VI).

This work presents a comprehensive study of the crystal structure, spectral properties (IR and UV-Vis), thermal behavior, and antimicrobial activity of homopiperazinium dichromate (C5H14N2)Cr2O7(VI). X-ray diffraction reveals that the compound crystallizes in the monoclinic space group P21/c, with unit cell dimensions a=8.7275(8)Å, b=10.5769(11)Å, and c=14.7467(10)Å and β=122.941(4)°. The crystal packing is stabilized by intermolecular N-H…O and C-H…O hydrogen bonds, with Hirshfeld surface analysis revealing dominant O…H/H…O interactions contributing 80.5% to the overall crystal cohesion. UV-Vis absorption bands are observed at 279, 354, and 446nm, with an estimated band gap energy of 3.019eV, indicating high stability and moderate optical activity. Thermal analysis shows an intense endothermic fusion peak followed by continuous decomposition, leading to chromium oxide formation. Antimicrobial tests demonstrate significant inhibition activity against tested pathogens, including notable antifungal effects against Candida albicans. These results highlight the potential of this hybrid material in antimicrobial development and photochemical applications.