Synthesis, Spectroscopic, Antimicrobial Activity and Computational Studies of Some Homoleptic and Heteroleptic Metal(II) Complexes of 2-Furoic Acid Hydrazone

Homoleptic Co(II), Cu(II) and Ni(II) complexes of a hydrazone derived from 3-acetyl-2-hydroxy-6-methyl-4H-pyran-4-one (dehydroacetic acid) and 2-furoic acid hydrazide, and their heteroleptic analogues with 2,2'-bipyridine were synthesized. The complexes were characterized by spectroscopic methods (ESI-MS, IR and NMR), elemental analysis, magnetic susceptibility and molar conductance measurements. The homoleptic complexes adopted octahedral geometry, while the heteroleptic analogous had four-coordinate tetrahedral (Co and Cu complexes) and square-planar (Ni complex) geometries. The homoleptic complexes were non-electrolytes, while the heteroleptic complexes were 1:1 electrolytes in DMSO. Antimicrobial experiments indicated that [Cu(L)2] and [Cu(L)(bipy)](CH3COO) had the best antibacterial activities, with MIC of 31.2 and 61.5 µg/ml against Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212, respectively. Molecular docking determined that [Cu(L)(bipy)]·CH3COO had the highest binding energy and hydrogen bonding interactions with one of the active sites of amino acid residue (LEU73). Density functional theory (DFT) calculations of the complexes revealed that [Cu(L)(bipy)]·CH3COO possessed low energy gap, suggesting a higher activity and ability to donate electrons to electron-accepting species of biological targets. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimInyuvesi Yakwazulu-Natali University Of Nigeria NsukkaAuthors thank the University of Nigeria, Nsukka, Zonguldak Bulent Ecevit University, Zonguldak, Coal City University, Enugu, CHPC (www.chpc.ac.za) and University of KwaZulu-Natal, Durban for operational and infrastructural support. We are also grateful to Ekele Dinneya-Onuoha of the Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka for technical support

Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a benzohydrazone derivative: Spectroscopic, DFT, antipathogenic and DNA binding studies

Co(II), Ni(II) and Cu(II) complexes of a benzohydrazone derivative, obtained by the reaction of dehydroacetic acid and benzohydrazide, have been synthesized and characterized by conventional spectroscopic techniques, elemental analyses, magnetic susceptibility and conductivity methods, and screened for antibacterial, DNA binding and cleavage properties. Spectroscopic, magnetic and elemental analyses indicated a square planar and a tetrahedral geometries with formula, [M(L) 2 ], for the Ni(II) and Co(II) complexes, respectively, while a tetrahedral geometry of formula, [ML(H 2 O) 2 ]·CH 3 COO - , was adopted for the Cu(II) complex. The Ni and Co complexes were non-electrolytes with molar conductance within the range of 11.46–14.01 ? -1 cm 2 mol -1 , while the copper complex was a 1:1 electrolyte in DMSO with a value of 55.11 ? -1 cm 2 mol -1 . The copper complex had the highest antibacterial activity against Staphylococcus aureus (ATCC 29213). DNA cleavage activities of the compounds, evaluated on pBR322 DNA by agarose gel electrophoresis in the presence and absence of peroxide oxidant (H 2 O 2 ) and free radical scavenger (DMSO), indicated no activity for the ligand, and a moderate activity for the complexes, with the copper complex cleaving more efficiently in the presence of H 2 O 2 . Upon evaluating the complexes for antimicrobial and A-DNA activities using molecular docking technique the copper complex was found to be most effective against Gram-positive (S. aureus) bacteria. [CuL(H 2 O) 2 ] + showed good interaction with hydrogen bonding with the major-groove (C 2 .G 13 base pair) of A-DNA. Density functional theory (DFT) calculations of structural and electronic properties of complexes revealed that [CuL(H 2 O) 2 ] + had a smaller HOMO-LUMO gap, suggesting a higher tendency to donate electrons to electron accepting species of biological targets. © 201