Syntheses, characterization, and antimicrobial studies of Ni(II), Cu(II), and Co(III) complexes with an N-pendant azamacrocyclic chelator

Condensation of 1,2-diamino propane with acetone in the presence of perchloric acid furnished a 14-membered octamethyl tetraazamacrocycle, Me-8[14]diene center dot 2HClO(4), which further produced a mixture of isomeric ligands, Me-8[14]anes (L-A, L-B, and L-C), on reduction with NaBH4 and subsequent extraction with CHCl3 (pH > 12). The isomers were separated by fractional crystallization from xylene. Interaction of L-C with excess acrylonitrile afforded an N-pendant derivative, L, in which two cyanoethyl L-CX,L- groups were attached to less crowded nitrogen atoms (N-4 and N-11). Upon the interaction of L-CX with Ni(CH3COO)(2)center dot 4H(2)O, Cu(ClO4)(2)center dot 6H(2)O, and Co(CH3COO)(2)center dot 4H(2)O, square planar [Ni(L-CX)](ClO4)(2) and [Cu(L-CX)](ClO4)(2) and octahedral trans-[Co(L-CX)Cl-2](ClO4), respectively, were produced. Axial substitution reactions of trans-[Co(L-CX)Cl-2](ClO4) with KCNS, KM (M = NO3, Br, or I), and NaNO2 afforded substituted trans-[Co(L-CX)(NCS)(2)](SCN), trans-[CoLCX(X)(2)](ClO4), and trans-[Co(L-CX)(NO2)(2)](ClO4), respectively. The ligand and corresponding metal complexes were characterized based on the analytical, spectroscopic, magnetic moment, and molar conductivity data. Gram-positive and gram-negative bacteria and different fungi were used to evaluate the antibacterial and antifungal activities of the ligand and its metal complexes. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study involved the synthesis and characterization of a series of ligands and metal complexes using various chemical methods. The antibacterial and antifungal activities of these compounds were evaluated on gram-positive and gram-negative bacteria as well as different fungi through experiments.