Chromium trioxide-amino acid complexes: Synthesis, characterization, and computational calculations

In this work, six different amino acids, including L-Leucine (Leu), L-Isoleucine (Ile), L-Methionine (Met), L-Histidine (His), L-Arginine (Arg), and L-Tryptophan (Trp), reacted with chromium trioxide (CrO3) in a methanol solvent. The synthesis of the Amino acid-CrO3 products was carried out through several steps, including the preparation of individual solutions of amino acids in methanol, the addition of the methanolic CrO3 solution, refluxing the two components (CrO3 and amino acid) for 3 hours at 70 °C, separating the precipitates, and purifying the final Amino acid-CrO3 products. The amino acids captured CrO3 through both amino and carboxylate groups, as indicated by the FT-IR spectra of the synthesized products. The synthesized products underwent thermal decomposition via two-stage decomposition steps, as evidenced by their thermograms. Finally, the density functional theory (DFT) method was applied to calculate the energy parameters and encompassing geometry optimization of the synthesized products. Computational calculations indicated that the synthesized Amino acid-CrO3 products have lower total energy and are more stable compared to their corresponding free amino acids. The lower total energy and increased stability of the Amino acid-CrO3 products suggest their potential applications in various fields, including catalysis, materials science, and biomedical engineering. KEY WORDS: Amino acids, Metal complexes, CrO3, Geometry optimization, Computational calculations Bull. Chem. Soc. Ethiop. 2025, 39(10), 1989-2004. DOI: https://dx.doi.org/10.4314/bcse.v39i10.9