Zinc(II) complexes bearing N,N,S ligands: Synthesis, crystal structure, spectroscopic analysis, molecular docking and biological investigations about its antifungal activity

In the present work, the synthesis, characterization, antifungal activity, molecular docking study and in silico approach of five thiosemicarbazone derivatives and their corresponding zinc(II) complexes are described. The compounds were characterized by elemental analysis, IR, UV-Vis and NMR spectroscopic measurements, molar conductivity measurements, emission spectra, high-resolution mass spectrometry and X ray study. The antifungal activity of the free ligands and synthesized compounds was preliminarily evaluated against Candida albicans (ATCC 90028), Candida tropicalis (ATCC 13803) and Candida glabrata (ATCC 2001), by the minimum inhibitory concentration (MIC) assay. Two complexes, 4 (MIC = 3.18 to 6.37 mu M) and 5 (MIC = 25.95 mu M for all) showed promising results, being highly active against all strains evaluated. The X-ray analyses shown that the complex 2 crystallizes in the centrosymmetric space group P2(1)/c of the monoclinic system and the coordination sphere around zinc(II) atom is better described as slightly distorted octahedral. The Hirshfeld surface (HS) analysis showed that non-classical H center dot center dot center dot H and C center dot center dot center dot H/H center dot center dot center dot C contacts contribute with 65.9% while the S center dot center dot center dot H and N center dot center dot center dot H (21%) and Cl center dot center dot center dot H and O center dot center dot center dot H interactions (12%) complete the HS area. The molecular docking results, performed against CYP51 enzyme (sterol 14 alpha-demethylase) of C. albicans and C. glabrata shows that the complexes 4 (Delta G = 10.75 and 12.90 kcal/ mol) and 5 (Delta G = 11.12 and 14.53 kcal/ mol) showed the highest binding free energies of all compounds. The ADME-Tox (absorption, distribution, metabolism, excretion and toxicity) in silico parameters evaluated showed promising results for all compounds.