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Amphetamine in fingerprints is predicted to be detectable using fingerprinting reagents by UV-vis spectroscopy and a visible colour change.

Multicobalt(II) two-dimensional layer coordination polymer {[Co(bitbu-OMe)2(NCS)2]·2MeOH}n (1) was synthesized using a bis-imidazole ligand having a steric hindrance, tert-butyl, and one methoxy group expressed by bitbu-OMe (bitbu-OMe = 1,1’-[(5-tert-butyl-2-methoxybenzene-1,3-diyl)dimethanediyl]bis(1H-imidazole). Since there are two methanol molecules trapped inside each void within 1, the investigation of small organic matters removal from organic wastewater was conducted in order to reveal its ability in the purification process. The research findings indicate that 1 has the ability to capture methanol, acetone, acetonitrile, and tetrahydrofuran in organic wastewater with removal ratios of 29.17%, 63.22%, 42.77%, and 21.24%, respectively.

In this research work, the extraction, characterization, device fabrication, and theoretical investigation of Hibiscus sabdariffa plant extract, for possible application in solid DSSCs, are reported. The plant extract was analyzed using FT-IR and UV–Vis spectrophotometry. Polyaniline on graphene was used as the counter electrode whereas titanium (IV) oxide was used as the photo anode for the fabricated DSSCs. The experimental results obtained for the open circuit voltage, short circuit current density, field factor, maximum power and conversion efficiency are 0.925 V, 0.073 A/cm2, 1.43, 1.04 W, and 0.044 % respectively. The excited states of anthocyanin (delphinidin) and quercetin, the most stable structures of Hibiscus sabdariffa plant extract, were studied using density functional theory method. In addition, the theoretical open circuit voltage, light harvesting efficiency, coupling constant, free energy change, and HOMO–LUMO energy gap were predicted for the photovoltaic properties. The theoretical results suggest that quercetin has relatively better photovoltaic properties and, hence, potentially a better dye for solar cell application.

One of the approaches adopted, as the first treatment method, in previous pandemic viruses before the production of new vaccines or drugs, is to evaluate the effectiveness of existing drugs. Sometimes, it is known that the combination of drugs provides better treatment by increasing the activity of the drugs due to mutual interactions. In this work, we used quantum theory of atoms in molecules and density functional theory to examine the structure and activity relationship between Favipiravir (FPV), a potential antiviral drug for ribonucleic acid viruses, and an inhibitor of influenza virus, and Ibuprofen (IBP), a nonsteroidal anti-inflammatory drug. The drug-likeness evaluations of IBP horizontal ellipsis FPV were also performed. It was observed that FPV and IBP interact in several ways via hydrogen bonding (HB) leading to changes in the activities of the combined drug and IBP horizontal ellipsis FPV is predicted to be orally bioavailable. It was also found that the highest occupied molecular orbital (HOMO) is located on IBP and the lowest unoccupied molecular orbital (LUMO) is distributed over FPV. The biological activity of the combined drug system is increased because of the small HOMO-LUMO energy gap value, partially covalent and non-covalent HB interactions. Communicated by Ramaswamy H. Sarma

Quantum chemical computations generate output files with data. The processing of these data generates results which are presented in a target document, such as a manuscript or supporting information (SI). Several tools and techniques can be employed to facilitate the transfer of data which, otherwise, can be time-consuming with a large number of files. However, depending on the user’s technical knowledge or expertise with the software, additional time has to be invested to set up the software or use the tools. In addition, to the best of the authors’ knowledge, the tools currently available do not provide an option to transfer the data from the output files directly to the target document without the use of custom scripts. The ExcelAutomat tool (Laloo et al., J. Comput. Aided Mol. Des. 2017, 31, 667 and Laloo et al., J. Comp. Chem. 2019, 40, 3) is spreadsheet-based and was developed in-house to facilitate the steps involved in the processing of computational files. The tool was adapted to facilitate the generation of SI in an update of ExcelAutomat 1.4. A graphical user interface was designed where the options for the generation of SI can be defined. ExcelAutomat 1.4 is compatible with Microsoft Excel and the open-source LibreOffice Calc. The extensible tool supports various software packages and parameters by interfacing with the cclib library and through built-in codes. The tool provides a method to transfer data from output files directly to a Microsoft Word or LibreOffice Writer document and can reduce the number of steps, tools or technical knowledge needed to generate SI, especially for users who are familiar with Microsoft Excel or LibreOffice Calc.

The proposed SN2 reactions of a hindered organophosphorus reactant with aliphatic and aromatic nucleophiles [Ye et al., Org. Lett., 2017, 19, 5384–5387] were studied theoretically in order to explain the observed stereochemistry of the products.

The thermodynamics and mechanisms of the atmospherically relevant reaction dimethyl sulphide (DMS) + atomic chlorine (Cl) were investigated in the absence and presence of a single water molecule, using electronic structure methods. Stationary points on each reaction surface were located using density functional theory (DFT) with the M06-2X functional with aug-cc-pVDZ (aVDZ) and aug-cc-pVTZ (aVTZ) basis sets. Then fixed point calculations were carried out using the UM06-2X/aVTZ optimised stationary point geometries, with aug-cc-pVnZ basis sets (n = T and Q), using the coupled cluster method [CCSD(T)], as well as the domain-based local pair natural orbitals coupled cluster [DLPNO-UCCSD(T)] approach. Four reaction channels are possible, formation of (A) CH3SCH2 + HCl, (B) CH3S + CH3Cl, (C) CH3SCl + CH3, and (C′) CH3S(Cl)CH3. The results show that, in the absence of water, channels A and C′ are the dominant channels. In the presence of water, the calculations show that the reaction mechanisms for A and C formation change significantly. Channel A occurs via submerged TSs and is expected to be rapid. Channel B occurs via TSs which present significant energy barriers indicating that this channel is not significant in the presence of water relative to CH3SCH2 + HCl and DMS·Cl adduct formation, as is the case in the absence of water. Channel C was not considered as it is endothermic in the absence of water. In the presence of water, pathways which proceed via (a) DMS·H2O + Cl, (b) Cl·H2O + DMS and (c) DMS·Cl + H2O were considered. It was found that under tropospheric conditions, reactions via pathway (b) are of minor importance relative to those that proceed via pathways (a) and (c). This study has shown that water changes the mechanisms of the DMS + Cl reactions significantly but the presence of water is not expected to affect the overall reaction rate coefficient under atmospheric conditions as the DMS + Cl reaction has a rate coefficient at room temperature close to the collisional limit.

Graphical abstract Hydroxychloroquine (HCQ) and favipiravir (FPV) are known to be effective antivirals, and there are reports about their use to fight the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) despite that these are not conclusive. The use of combined drugs is common in drug discovery, and thus, we investigated HCQ and FPV as a combined drug. The density functional theory method was used for the optimization of geometries, spectroscopic analysis and calculation of reactivity parameters. The quantum theory of atoms in molecules was applied to explain the nature of the hydrogen bonds and confirm the higher stability of the combined drug. We also evaluated the absorption, distribution, metabolism and excretion (ADME) parameters to assess their drug actions jointly using SwissADME. The preliminary findings of our theoretical study are promising for further investigations of more potent and selective antiviral drugs. Supplementary Information The online version contains supplementary material available at 10.1007/s11696-021-01946-8.

In order to understand the atmospheric implication of the chlorinated hydrofluoroolefin (HFO), the geometrical structures and the IR absorption cross sections of the stereoisomers 1-chloro-3,3-difluoropropene were studied using the B3LYP/6-31G(3df) and M06-2X/6-31G(3df) methods in the gas phase. The cis-trans isomerization was assessed using the M06-2X/6-311++G(3df,p)//6-31+G(3df,p) method. The latter method was also employed for thermochemistry and the rate coefficients of the reactions of •OH with the cis- and trans-isomers in the temperature ranging from 200 to 400 K. The computational method CCSD/cc-pVTZ//M06-2X/6-31+G(3df,p) was used to benchmark the rate coefficients. It turns out that, the trans-isomer is more stable than cis-isomer and the trans- to cis-isomerization is thermodynamically unfavorable. The rate coefficient follows the Gaussian law with respect to the inverse of temperature. At the global temperature of stratosphere, the calculated rate coefficients served to estimate the atmospheric lifetime along with the photochemical ozone creation potential (POCP). This yielded lifetimes of 4.31 and 7.31 days and POCPs of 3.80 and 2.23 for the cis- and trans-isomer, respectively. The radiative forcing efficiencies gave 0.0082 and 0.0152 W m−2 ppb−1 for the cis- and trans-isomer, respectively. The global warming potential approached zero for both stereoisomers at 20, 100, and 500 years time horizons.

In this study, a series of sulfonamide chalcones derivatives was synthesized and its chemical structures were confirmed by spectral characteristics. The synthesized compounds were evaluated for their tyrosinase inhibitory activities along with molecular docking study. The tyrosinase inhibitory results indicated that compounds 5b, 5c, 5f, 5g and 5h displayed the significant tyrosinase inhibitory activity and comparable to the standard drug (kojic acid). Compound 5c exhibits the most potent tyrosinase inhibition among the synthesized compounds with IC50 = 0.43±0.07 mM, L-DOPA as the substrate, and better than that of the standard kojic acid (IC50 = 0.60±0.20 mM). Molecular docking studies showed that the binding mode of some compounds is in the tyrosinase binding pocket surrounding the copper in the active site. The correlation between the docking results with IC50 values showed that the binding mode prediction of the test compounds would also be convincing. This comprehensive study allows for a possible mechanism for the antityrosinase activity of the sulfonamide chalcones. These sulfonamide chalcones bind to copper atoms of tyrosinase which responsible for the catalytic activity of tyrosinase. These compounds may be used as a lead for rational drug designing for the multi-functional tyrosinase inhibitor.

We present the results of the analysis of 2,2,6,6-tetramethyl-4-oxo-piperidinium nitrate isolated from the stem bark of

The coating industry is one of the most important consumers of water and chemicals and consequently is a major water polluter in Mauritius. The focus of this study was to characterise wastewater generated by a coating industry in Mauritius. The objectives were to develop a wastewater sampling strategy and to analyse the pollutant parameters as per Mauritian regulations. The wastewater samples were analysed for physicochemical properties and metal abundances over a period of 6 months. The physicochemical parameters analysed were pH, electrical conductivity (EC), true colour, total suspended solids (TSS), biological oxygen demand (BOD

The presence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HM) in wastewater is a major challenge to the environment as various approaches have been used to remediate these contaminants from the environment. Zerovalent iron-titanium oxide nanoparticle (ZVI-TiO2 NPs) was synthesized by wet reflux in an inert environment using nitrogen gas and sodium borohydride as reducing agents. Characterization was carried out using a scanning electron microscope (SEM) coupled with electron diffraction X-ray (EDX) and Fourier transform infrared spectrophotometer (FTIR). Assessments of the wastewater were carried out with atomic absorption spectrophotometer (AAS) for HM and a gas chromatography-mass spectrophotometer (GCMS) for PAHs to determine the initial concentration (C i) compared with permissible limits of surface water and adsorption capacity with ZVI-TiO2 NPs (C f), respectively. The results obtained indicate a percentage yield of 65.51 ± 0.01 of ZVI-TiO2 NPs, with a particle size of 100 nm, weight composition of iron, titanium, and oxygen at 49.69, 5.24, and 35.41 g, respectively. FTIR shows a vibrational change of 3465, 2929, and 1641 cm−1 of OH, CH, and CO group needed for metal binding and adsorption. Remediation of HM after acid digestion gave effective removal of zinc, copper, cadmium, cobalt, and lead at an adsorption capacity of 64.29, 54.83, 53.13, 48.39, and 42.66% respectively. The adsorptions of benzo[a]pyrene, fluoranthene, pyrene, benzo[b]fluoranthene, and perylene were 77.87, 67.85, 52.17, 29.50, and 25.45%, respectively. These results indicate that metal/metal oxide (ZVI-TiO2) nanoparticles have a high potential in the remediation of heavy metals and PAHs from the water ecosystem.