Synthesis, Characterization, and Antibacterial Activities of 1H-Imidazo [5, 6-f] [1,10] Phenanthroline-2(3H)-Thione and Its Ni(II) and Cu(II) Complexes

Radiet Anbessie Tirkeso,Gebru G/Tsadik Amdemichael,Tilahun Wubalem Tsega

doi:10.1155/2019/7145857

Radiet Anbessie Tirkeso, Gebru G/Tsadik Amdemichael + Show 1 more

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https://doi.org/10.1155/2019/7145857

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Abstract

As multidrug resistant pathogens are emerging, the search for novel potent drug candidates is ever going. Heterocycles are known by their broad spectrum of biological activities, so a search for a new drug from heterocycles can elevate the chance of success. The aim of this study was to obtain novel potent antimicrobial compounds. In line with this, 1H-imidazo [5, 6-f] [1,10] phenanthroline-2(3H)-thione and its complexes (Ni(II) and Cu(II)) were synthesized, characterized, and evaluated against bacterial strains. The compounds were characterized by elemental analyses (C, H, N, and S), FT-IR,1H-NMR,13C-NMR, AAS, UV-Vis spectra, and molar conductivity measurement. The results showed that the ligand is bidentate, and the molar conductivity measurement indicates that complexes are electrolytic. Electronic spectral study showed octahedral and distorted octahedral geometry for the Ni(II) and Cu(II) complex, respectively. The ligand and its complexes were screened against four bacterial strains using disk diffusion method. The result revealed that the Ni(II) complex showed more bioactivity than gentamicin againstStaphylococcus aureusandEscherichia coli, while the Cu(II) complex is more active than the Ni(II) complex againstBacillus subtilis.Both Cu(II) and Ni(II) complexes exhibit higher antibacterial activities than the free ligand.

Highlights

Heterocyclic chemistry is a branch of organic chemistry deals with two third of organic compounds, called heterocycles
A large number of antibiotics and chemotherapeutic agents are available, treatment of infectious diseases is still a challenging problem due to the outbreak of new infectious diseases as well as medicinal drug-resistant pathogens [5] which makes the search for a novel potent drug candidate an indispensable strategy to overcome the challenge of drug-resistant pathogens
Synthesis and Physical Characteristics of the Ligand and Its Complexes. e synthesis of the new ligand is illustrated in Scheme2

Summary

Introduction

Heterocyclic chemistry is a branch of organic chemistry deals with two third of organic compounds, called heterocycles. Heterocycles contain heteroatoms such as sulfur, oxygen, or nitrogen as part of their ring structure. 1,10-phenanthroline derivatives have attracted considerable interest from both synthetic and medicinal chemists being the structural pattern in several natural biologically important compounds [3] and molecular scaffoldings for supramolecular assemblies, building blocks for the synthesis of metallodendrimers, thin films of luminescent complexes, and ligands of synthesis of ring-opening metathesis polymerization (ROMP) monomer [4]. Reported literatures have suggested that heterocycles and their derivatives have excellent broad spectrum of biological activities [3, 6], so a search for a new drug from heterocycles is supposed to uplift the chance of success. It was observed that the Ni(II) complex of the new ligand was more active than gentamicin against S. aureus, E. coli, and P. aeruginosa

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