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• Structure elucidation and optimization were accomplished using spectral data and the DFT technique. • Solute-Solvent interactions reported on UV–Visible investigation, using TD-DFT, comprehension of stability, and biological activity. • Multiwave function analysis, such as ELF, LOL, and RDG, were performed to better understand surface electron density, delocalization, localized orbital, and weak interaction. • The FMO, MEP, and Hirshfeld charges of the molecule, as well as one electron transport pathway, were discovered. • The antioxidant activity and anti-inflammatory impact were investigated, and the in-vitro bioassay results were verified. Eremostachys vicaryi Benth. Ex Hook. f. (Labiatae), a Pakistani (Baluchistan) herbal medicinal plant commonly known as "Stagh," which has a sharp taste and smell. It acts as an antiseptic and antimicrobial agent and is used for fish poisoning, treating skin diseases, and holding a cooling effect. Following the assessment of the plant extract's cytotoxic and phytotoxic assays using phytochemical screening, the antioxidant and anti-inflammatory properties of the pure ingredients that were separated from the ethyl acetate soluble fractions have been evaluated. The bioassay-guided fractionation and purification of E. vicaryi B. crude methanol extract yielded two isoflavones (1–2) that showed promising antioxidative activities with DPPH and cytochrome-c-reduction assays. Compounds 1 and 2 have shown considerable anti-inflammatory efficacy, 1 being a good inhibitor of the superoxide within the living system. Initial assumptions on the one-electron transfer process indicated that Compound 1 has a smaller ionization potential value compared to Compound 2 and so has greater antioxidant potential than its predecessor, isoflavone. Moreover, the anti-inflammatory and antioxidant activity of isoflavones was also probed by first-principles calculations. Based on the findings, it has been concluded that the crude extract of E. vicaryi B. and its organic components exhibit noteworthy phytotoxic and cytotoxic properties. The isolated pure isoflavones 1 and 2 showed significant antioxidant and anti-inflammatory activities. Solute-solvent interactions were studied and reported for both compounds. An analysis was conducted on the UV–Vis electronic transition for different solvents. Using a Multiwave function analyzer the topological findings such as ELF, LOL, and RDG were done to comprehend the surface electron density, delocalization, localized orbital, and weak interaction in the compounds. The antioxidant activity is evaluated by radical methods using DPPH, and cytochrome-c-reduction assays using ascorbic acid as a standard. Through cell-based respiratory burst testing, the anti-inflammatory activity of standard indomethacin was examined. The ground state geometries of isoflavones and reference compounds were optimized by Density Functional Theory- (DFT) by computing various electronic properties. In-vitro bioassay results were validated by first-principles calculations. [ABSTRACT FROM AUTHOR]

A new highly selective fluorescent turn-on probe (RS4) possessing indolinium moiety has been designed and synthesized for the detection of cyanide ion. The probe RS4 displays instantaneous, highly selective and sensitive recognition of cyanide ion over other common anions via change in color and enhancement in fluorescence. Nucleophilic addition of cyanide to the indolinium C-atom leads to the enhancement in fluorescence (λ em 481 nm; Blueish-green emission) and decolourization due to different intramolecular charge transfer (ICT) process. The binding constant of the 1:2 RS4 /CN¯ adduct is determined to be 2.3 × 104 M−1. The limit of detection of cyanide by RS4 is estimated to be 21 nM. Density functional theory (DFT) based calculations strongly substantiate the results of the experimental investigations. Importantly, the probe detects cyanide ion in agro-products (cassava powder and bitter almond), which demonstrates its value to practical application. • The probe senses cyanide with color change and fluorescent enhancement. • The detection mechanism involves nucleophilic addition of CN− at indolinium C-atom. • Sensing mechanism was delineated using spectral and DFT studies. • The probe successfully sensed CN− of cyanogenic glycoside in agro-products. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein, two new thiazole derivatives: ethyl2-(2-benzylidenehydrazinyl)thiazole-4-carboxylate (3) and ethyl2-(2-(2-hydroxybenzylidene)hydrazinyl)thiazole-4-carboxylate (4) were synthesized by cyclization of 1-benzylidenethiosemicarbazide with ethyl bromopyruvate. The synthesis was validated by spectroscopic techniques like FTIR, 1H- NMR, 13C-NMR and chemical structure of title compounds 3 and 4 has been determined using SC-XRD. Ancillary to experimental analysis, DFT calculations with B3LYP/6-311 + G (d,p) level were performed for comparative analysis of FT-IR spectroscopic data, optimized geometry, frontier molecular orbitals (FMOs), natural bond orbital (NBO) analysis and nonlinear optical (NLO) properties. Overall, experimental findings were supported by corresponding DFT computed results. TDDFT calculations were executed at M06/6-311 + G (d,p) level of theory to calculate the vertical electronic transition states. NBO analysis disclosed that intramolecular charge transfer and hyper-conjugative interactions among bonds provide stability to the investigated compounds 3 and 4. The global reactivity parameters calculated from energy of FMOs indicates that 3 and 4 enclose larger softness and fewer hardness values. NLO results of 3 and 4 were observed better than standard molecule recommended the NLO activity of said compounds. We hope that this joint experimental and computational insight may provide new ways for the utilization of title molecules as NLO material for optoelectronic applications. Image 1 • Two novel ethyl 2-(2-(2-substitutedbenzylidene)hydrazinyl)thiazole-4-carboxylate crystals were synthesized. • XRD, 1H NMR, 13C NMR, FT-IR and UV–Vis were performed for the characterization. • Computational study was done at B3LYP/6-311 + G (d,p) level for comparative analysis. • Comparative study reveals a good agreement between experimental and DFT results. • FMOs, NBO analysis and nonlinear optical (NLO) properties were calculated. [ABSTRACT FROM AUTHOR]

The pyrimidine ring is significantly distributed in nature due to its existence in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) as nitrogenous bases. The heterocyclic aromatic compounds have become an important pharmacophore due to promising applications in medicine and nonlinear optics (NLO) fields. Keeping in view of the significance of 4-thiopyrimidines derivatives, we selected phenyl pyrimidine derivatives namely: ethyl 4-((3-chlorobenzyl)thio)-6-methyl-2-phenylpyrimidine-5-carboxylate (1), (4-((4-chlorobenzyl)thio)-6-methyl-2-phenyl-pyrimidin-5-yl)methanol (2) and 4-((4-chlorobenzyl)thio)-5,6-dimethyl-2-phenylpyrimidine (3) for NLO study and comparative analysis. Overall, density functional theory (DFT) findings of structural parameters at B3LYP/6-311G(d,p) level show excellent concurrence with the experimental data which confirms the purity of 1 , 2 and 3. The vibrational analysis of 1 , 2 and 3 have been carried out by DFT calculations based on B3LYP/6-311G(d,p) level of theory. The natural bonding orbital (NBO) analysis has been used to get insight into non-covalent interactions. From DFT calculations, various parameters such as natural population analysis (NPA) atomic charges, HOMO–LUMO energies and global reactivity parameters have been obtained. The molecular electronic potential (MEP) and parametric molecular electrostatic potential (PMEP) have also been derived for 1 , 2 and 3. The photophysical properties of investigated molecules were estimated using time dependent DFT (TDDFT) at B3LYP/6-311G(d,p) level of theory. Nonlinear optical (NLO) analysis has also been carried out by DFT calculations with B3LYP/6-311G(d,p) functional. The NLO properties of 1 , 2 and 3 were observed larger as compared to the standard molecule indicating the considerable NLO character of all molecules especially recommended the NLO activity of 1 for optoelectronic associated hi-tech applications. Image 1 • Three novel phenyl pyrimidine derivatives 1 , 2 and 3 were studied. • Computational study was done at B3LYP/6-311G(d,p) level for comparative study. • Comparative study reveals a good agreement between XRD and DFT results. • FMO, NBO, global reactivity parameter, NPA, MEP, PMEP and NLO analysis were performed. • All studied compounds hold considerable NLO character and recommended for optoelectronic associated hi-tech applications. [ABSTRACT FROM AUTHOR]