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Abstract: Comparison of experimental and theoretical parameters pertaining to structural and spectral properties of two nickel(II) complexes containing triphenylphosphine and 5-methyl-N-(2-mercaptophenyl)salicylideneimine (1) or 5-chloro-N-(2-mercaptophenyl)salicylideneimine (2) are presented. The calculated structural results of these complexes show that the DFT can well reproduce the structure of title compounds. The UV, IR and NMR spectra of the title compounds are determined using both experimental and theoretical methods. The optical absorption properties of the title compounds are calculated using time-dependent density functional theory method (TD-DFT). The IR spectra are calculated from the harmonic vibrational frequencies at the ground-state geometry of the title-compounds. The NMR spectra are calculated using the gauge-independent atomic orbital (GIAO) method. The results calculated using theoretical methods coincide well with the experimental results. [Copyright &y& Elsevier]

Two heterocyclic azole compounds, 3-(2,3-dihydrobenzo[d]thiazol-2-yl)-4H-chromen-4-one ( SVS1 ) and 5-(1H-indol-3-yl)-4-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione ( SVS2 ) were obtained unexpectedly from 2-aminothiophenol and 4-oxo-4H-chromene-3-carbaldehyde (for SVS1 ), and ( E )-2-((1H-indol-3-yl)methylene)-N-methylhydrazine-1-carbothioamide in the presence of anhydrous FeCl 3 (for SVS2 ), respectively. The compounds were well characterized by analytical and spectroscopic tools. The molecular structures of both the compounds were determined by single crystal X-ray diffraction (XRD) study. The results obtained from density functional theory (DFT) study revealed the molecular geometry and electron distribution of the compounds, which were correlated well with the three-dimensional structures obtained from the single crystal XRD. DMol 3 was used to calculate quantum chemical parameters [chemical potential ( µ ), global hardness ( η ), global softness ( σ ), absolute electronegativity ( χ ) and electrophilicity index ( ω )] of SVS1 and SVS2 . Molecular docking study was performed to elucidate the binding ability of SVS1 and SVS2 with SARS-CoV-2 main protease and human angiotensin-converting enzyme-2 (ACE-2) molecular targets. Interestingly, the binding efficiency of the compounds with the molecular targets was comparable with that of remdesivir (SARS-CoV-2), chloroquine and hydroxychloroquine. SVS1 showed better docking energy than SVS2 . The molecular docking study was complemented by molecular dynamics simulation study of SARS-CoV-2 main protease- SVS1 complex, which further exemplified the binding ability of SVS1 with the target. In addition, SVS1, SVS2 and cisplatin were assessed for their cytotoxicity against a panel of three human cancer cells such as HepG-2 (hepatic carcinoma), T24 (bladder) and EA.hy926 (endothelial), as well as Vero (kidney epithelial cells extracted from an African green monkey) normal cells using MTT assay. The results showed that SVS2 has significant cytotoxicity against HepG-2 and EA.hy926 cells with the IC 50 values of 33.8 μM (IC 50  = 49.9 μM-cisplatin and 8.6 μM-doxorubicin) and 29.2 (IC 50  = 26.6 μM-cisplatin and 3.8 μM-doxorubicin), respectively., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 Elsevier B.V. All rights reserved.)