Synthesis, antimicrobial test and theoretical study of 3-((6-hydroxy- [1,1′-biphenyl]-3-yl)diazenyl)-4h-thieno[3,4-c]chromene-4-one and its Ni(II) complex

Background: For a long time, men have faced two major problems. The pollution linked to the use of fossil energies and the proliferation of microbes. To deal with these two problems, researchers are constantly looking for new molecules with extraordinary properties. It is in this perspective that we will study the influence of complexation on the biological, structural and electronic properties of 3- ((6-hydroxy- [1,1′-biphenyl]-3-yl)diazenyl)-4h-thieno[3,4-c]chromene-4-one (1). Methodology: The ligand (1) was synthesized by diazotation reaction and by insitu copulation of the diazonium salt with 2-phenylphenol. The complex (4) was prepared by reflux complexation reaction and for 6 hours of the ligand with Ni.Cl2.6H2O. The structural, electronic and optical properties of the compounds were evaluated using the Density Functional Theory method with the Becke 3-parameter Lee-Yan-Par (B3LYP) functional, in the pople basis and Los Alamos National Laboratory Two Double Zeta. The in vitro antimicrobial activity of the synthesized compounds was evaluated against four bacterial strains. Results : Biological results showed that the compound (1) with MIC values between 32 and 64 μg/mL has moderate activity against Escherichia coli ATCC25922, Salmonella typhi ATCC1408 and Enterococcus faecalis ATCC 29212. On the other hand, the compound (4) with MIC between 16 and 64 μg/mL also has moderate activity vis-à-vis all strains of bacteria tested and the greatest activity was observed on Escherichia coli ATCC25922 (MIC = 16). Theoretical simulations have shown that the complexation to create a more reactive entity than the starting ligand with the appearance of new nucleophilic sites. Conclusion: the complex obtained had a higher activity, a lower energy gap and the greater nucleophilic character than the ligand. The complexation of azo derivatives with metal salts could be an alternative for preparing new antimicrobial and photosensitizer compounds