Complexation of alkaline earth metals Mg2+, Ca2+, Sr2+ and Ba2+ with adrenaline hormone: Synthesis, spectroscopic and antimicrobial analysis

Adrenaline complexes with bivalent ions Mg2+, Ca2+, Sr2+ and Ba2+ in methanol at 60 oC were prepared. The prepared complexes were isolated and characterized using elemental analyses, conductivity measurements, mid infrared, Raman laser, UV-Vis., 1H–NMR spectra, X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). Upon the spectroscopic, conductivity and elemental analyses, the stoichiometric reactions indicated 1:2 (M:L) for Ca2+, Sr2+ and Ba2+ complexes [Ca(Adr)2(H2O)2](H2O)4Cl2, [Sr(Adr)2(H2O)2]Cl2 and [Ba(Adr)2(H2O)6]Cl2 while the molar ratio of 1:1 (M:L) for Mg2+ with a formula [Mg2(Adr)2(H2O)7]Cl4. The interpretation of Raman and infrared spectra confirmed the coordination mode, which was through the two-catechol moiety OH phenolic groups. The in vitro antibacterial activity of adrenaline chelates that have been tested against three gram-positive bacteria, two gram-negative bacteria, and two strains of fungus showed that antimicrobial activity of the metal chelates are more effective than the adrenaline free ligand. KEY WORDS: Adrenaline, heavy metals, infrared, biological outcomes Bull. Chem. Soc. Ethiop. 2023, 37(2), 357-372. DOI: https://dx.doi.org/10.4314/bcse.v37i2.9