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The current viral pandemic, coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), creates health, mental, economic, and other serious challenges that are better to say global crisis. Despite the existence of successful vaccines, the possible mutations which can lead to the born of novel and possibly more dangerous variants of the virus as well as the absence of definitive treatment for this potentially fatal multiple-organ infection in critically ill patients make us keep searching. Theoretically targeting human and viral receptors and enzymes via molecular docking and dynamics simulations can be considered a wise, rational, and efficient way to develop therapeutic agents against COVID-19. In this way, The RNA-dependent RNA polymerase (RdRP), main protease, and spike glycoprotein of SARS-CoV-2 as well as the human angiotensin-converting enzyme 2 receptor and transmembrane serine protease 2 are the most discussed and studied targets that play essential roles in the viral life and infection cycle. In the current in silico investigation, the guanidine functionality containing drugs and medicinal substances such as metformin, famotidine, neuraminidase inhibitors, antimalarial medications, anticancer drug imatinib, CGP compounds, and human serine protease inhibitor camostat were studied against the above-mentioned therapeutic targets and most of them (especially imatinib) have revealed an incredible spectrum of free docking scores and MD results. The current in silico investigation that its novel perspective of view is corroborated by the different experimental and clinical evaluations, confirms that the guanidine moiety can be considered as a missing promising pharmacophore in drug design and development approaches against SARS-CoV-2. Considering the chemical potency of this polyamine group in chemical interaction creation, the observed outcomes in this virtual screening were not surprising. On the other hand, the guanidine functional group has unique physico-chemical properties such as basicity that can make the target cells intracellular pH undesirable for the virus entry, uncoating, and cytosolic lifecycle. According to the obtained results in the current study that are interestingly confirmed by the previously reported efficacy of some the guanidine carrying drugs in COVID-19, guanidine as a potential multi-target anti-SARS-CoV-2 functional scaffold deserves further comprehensive investigations.The online version contains supplementary material available at 10.1007/s11696-022-02528-y.

Objective: This study focused on the application of wearable technology in the safety monitoring and early warning for subway construction workers. Methods: With the help of real-time video surveillance and RFID positioning which was applied in the construction has realized the real-time monitoring and early warning of on-site construction to a certain extent, but there are still some problems. Real-time video surveillance technology relies on monitoring equipment, while the location of the equipment is fixed, so it is difficult to meet the full coverage of the construction site. However, wearable technologies can solve this problem, they have outstanding performance in collecting workers’ information, especially physiological state data and positioning data. Meanwhile, wearable technology has no impact on work and is not subject to the inference of dynamic environment. Results and Conclusion: The first time the system applied to subway construction was a great success. During the construction of the station, the number of occurrences of safety warnings was 43 times, but the number of occurrences of safety accidents was 0, which showed that the safety monitoring and early warning system played a significant role and worked out perfectly.

Background: In WDM networks, there is a crucial need to monitor signal degradation factors in order to maintain the quality of transmission. This is more critical in dynamic optical networks as non-linear impairments are network state dependent. Moreover, PLIs are accumulative in nature, so the overall impact is increased tremendously as the length of signal path is increased. The interactions between different impairments along the path also influence their overall impact. Objective: Among the different impairments, the present work focuses on phase modulations owing to the intensities of signals themselves as well as the neighboring signals. It includes the influence of SPM, SPM and XPM, system parameters like signal power, wavelength and fiber parameters like attenuation coefficient, dispersion coefficient and their influence on Q-value and BER. Methods: The analysis is done through a single and two-channel transmitter system with varied power, wavelengths and system parameters. The corresponding optical spectrums are analysed. Results & Conclusion: It has been found that SPM and XPM pose broadening effect on spectrum without any effect on temporal distributions. The magnitude of signal power is among the parameters significantly influencing the broadening of spectrum. The higher the power, the more the magnitude of broadening. It has been found that in order to neglect the impact of input power; its magnitude must be kept below 20 mW. Also, the dispersion and attenuation value need to be carefully as they pose counteracting effect to SPM and XPM for certain values and hence can be used as compensation measures without any additional cost.

This study presents a novel material for highly efficient adsorption of sulforaphane based on SBA-15. The SBA-15 nanoparticles were synthesized using natural silica by hydrothermal method and functionalized with thiol and amine groups by the post-synthesis grafting procedure. All adsorbents were characterized by various techniques including BET, LAXRD, FT-IR, FE-SEM, and CHNS. The batch adsorption experiments revealed that the adsorption efficiency of SBA-15 for sulforaphane can be mainly influenced by the introduction of functional groups and the best adsorption performance was observed for amine-functionalized SBA-15 (SBA-15-NH2) compared to pure SBA-15 and thiol-functionalized SBA-15 (SBA-15-SH) with the highest adsorption efficiency of about 97%. Preliminary adsorption studies of sulforaphane onto SBA-15-NH2 were performed in aqueous solutions with different pH values and various organic solvents. Also, the effects of adsorbent dosage, contact time, and initial sulforaphane concentration on sulforaphane adsorption using SBA-15-NH2 were studied. Langmuir and Redlich-Peterson isotherm models were the best-fitting models for the experimental data, followed by Temkin, Freundlich, and Dubinin-Radushkevich models. The adsorption process could be well described by the pseudo-first-order kinetic model based on kinetic parameters, correlation coefficient, and error functions. Meanwhile, the intra-particle diffusion model showed a multi-linear plot with three steps demonstrating slow diffusion into mesopores as a rate-limiting step.

A novel quinazoline-based colorimetric sensor (probe 1) that detected Fe

The sensitivity and reactivity of a B36 borophene were inspected with regard to the drub cisplatinum, in the gas phase and in aqueous solution, applying density functional theory calculations. In the gas phase, the adsorption energy (Ead) was predicted to be −19.6 kcal/mol, and the drug adsorbed via its Cl and H atoms on the edge of the B36 borophene. We found that the B36 electronic properties are meaningfully sensitive to the cisplatinum drug, and so may be a potential sensor for cisplatinum detection. Because of a large HOMO destabilization upon the drug adsorption, the HOMO–LUMO gap (Eg) of the B36 borophene significantly decreased from 1.11 to 0.62 eV, increasing its electrical conductance. A short recovery time of 0.023 s was predicted for desorption of the cisplatinum drug from the B36 borophene surface at room temperature. Unlike the Eg, the Fermi level and work function of the B36 borophene were not changed detectibly by the process of drug adsorption. The adsorption of cisplatinum on the B36 sheet weakens in aqueous solution, and the Ead is −12.3 kcal/mol.

A practical and an efficient Schiff base fluorescent chemosensor, salicylidene-4-aminoantipyrinyl-4-aminophenol (A2) has been synthesized through the condensation procedure of 1-phenyl-2,3-dimethyl-4-(N-2-hydroxybenzylidene)-3-pyrazoline-5-one and 4-aminophenol. Compound A2 has displayed a considerable fluorescence enhancement with high selectivity and sensitivity toward Al3+ ion and exhibited an emission band at 484 nm, which contained a low detection limit (LOD) of 1.06 × 10−7 M. In accordance to the experimental study, DFT, TDDFT calculations, and the enhancement of fluorescence intensity might be attributed to the inhibition of Photoinduced Electron Transfer (PET) along with the Excited-State Intramolecular Proton Transfer (ESIPT). As it has been specified by Job's plot and DFT calculations, the binding stoichiometries of A2 with Al3+ are 1:1, while the association constant (Ka) of Al3+ has been calculated and observed to be 2.67 × × 105 M−1. Furthermore, the binding behavior and sensing mechanism of A2 with Al3+ have been confirmed through the experiments of 1H NMR titration.

An efficient, green, one-pot, and three-component protocol has been reported for the stereoselective synthesis of a new class of spiro thiazolidines. A series of spiro-heterocycle derivatives were produced stereoselectively in high yields by the reaction of 5-arylidene thiazolidine-2,4-diones, isatin, and secondary amino acids in the presence of MnCoCuFe2O4@L-proline (MCCFe2O4@L-proline) magnetic nanorods as a novel nanocatalyst. The synthesized catalyst was fully characterized for thermal stability, magnetic properties, and other physicochemical properties via numerous techniques. It was applied as an efficient and reusable catalyst for the synthesis of endo-isomers of spirocyclic pyrrolidine/pyrrolizidine/pyrrolothiazolidine derivatives in high yield. The regioselectivity and stereochemistry of these heterocyclic spiro-compounds were established by 1H, 13C, HMBC, HSQC, and COSY NMR spectroscopy techniques. The main attractive characteristics of the presented protocol are high yield, high level of diastereoselectivity, and easy recovery of catalyst without significant loss of its catalytic activity.

The highly contagious Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which is a newborn infectious member of the dangerous beta-coronaviruses (β-CoVs) following SARS and MERS‐CoVs, can be regarded as the most significant issue afflicting the whole world shortly after December 2019. Considering CoVs as RNA viruses with a single-stranded RNA genome (+ssRNA), the critical viral enzyme RNA dependent RNA polymerase (RdRp) is a promising therapeutic target for the potentially fatal infection COVID-19. Nicotinamide riboside (NR), which is a naturally occurring analogue of Niacin (vitamin B3), is expected to have therapeutic effects on COVID-19 due to its super close structural similarity to the proven RdRp inhibitors. Thus, at the first phase of the current molecular docking and dynamics simulation studies, we targeted SARS-CoV-2 RdRp. On the next phase, SARS-CoV RdRp, human Angiotensin-converting enzyme 2, Inosine-5’-monophosphate dehydrogenase, and the SARS-CoV-2 Structural Glycoproteins Spike, Nonstructural viral protein 3-Chymotrypsin-like protease, and Papain-like protease were targeted using the docking simulation to find other possible antiviral effects of NR serendipitously. In the current study, the resulted scores from molecular docking and dynamics simulations as the primary determinative factor as well as the observed reliable binding modes have demonstrated that Nicotinamide Riboside and its active metabolite NMN can target human ACE2 and IMPDH, along with the viral Spro, Mpro, PLpro, and on top of all, RdRp as a potential competitive inhibitor., Graphical Abstract Image, graphical abstract

A novel fluorescent chemosensor calix[4]arene L, containing two fluorogenic coumarin units at the lower rim has been synthesized via click reaction. The structure of this chemosensor, was characterized by IR, NMR spectra and elemental analysis. Ion-binding properties of L were investigated in acetonitrile with different metal ions and the recognition process was monitored by fluorescence, UV-Vis and 1H NMR spectral changes. In comparison with other metal ions, chemosensor L showed a specific selectivity toward copper ions‏. The Job plot analysis revealed that the binding between L with Cu2+ is in 1:1 stoichiometry. The association constant (Ka) for the complex L.Cu2+ was found to be 1.6 × 105 M−1. The limit of detection of the sensor L was determined to be 5.4 × 10−7 M. This sensitive and selective chemosensor was successfully applied for the detection of Cu2+ ions in human blood serum with 90–100% recovery.

Using density functional theory calculations, we investigated the potential application of Al12N12 and B12N12 nanoclusters as an electronic or work function type sensor for acetylsalicylic acid (ASA) drug detection. The drug tends to be adsorbed on the surface of both AlN and BN clusters via its –COOH group with adsorption energies about − 62.8 and − 21.9 kcal/mol, respectively. The AlN nanocluster is neither electronic nor work function based sensor for ASA because of a low sensitivity, and a huge recovery time (~ 9.8 × 1038 s). But the response of BN nanocluster is completely different, and its electrical conductivity is largely increased in the presence of ASA drug due to the large stabilization of LUMO level. We concluded that the BN nanocluster may be a promising candidate to detect the ASA drug with a short recovery time about 109 s and a high electronic sensitivity. As the work function of the BN nanocluster is not affected by the ASA adsorption, it cannot be used as a work function type sensor.

A novel Schiff base fluorescent sensor N,N′-bis(salicylidene)-2,6-bis(4-aminophenyl)-4-phenylpyridine (P3) was synthesized through condensation of 2,6-bis(4-aminophenyl)-4-phenylpyridine and 2-hydroxybenzaldehyde. The obtained results from fluorescence analysis revealed that by excess of Cr3+ to P3, a remarkable increase was observed in the fluorescent intensity of the Schiff base at 663 nm with the ratio of CH3CN/H2O (95/5%), even though the other cations would likely have no impact on the fluorescence intensity. The cause of this trend might be ascribed to the formation of a 1:1 stoichiometric P3-Cr3+ complex, confirmed by Job's plot, which is resulted in preventing the photo-induced electron transfer (PET) process. From fluorescence titration, the association constant Ka was gained 2.28 × 105 M−1 and the limit of detection (LOD) was determined to be 1.3 × 10−7 M. Furthermore, the optimized structure together with the electronic spectra of the proposed complex was determined by DFT and TDDFT calculations.

Background: Bioremediation of groundwater and soil contamination is more economical than physicochemical remediation. The present study focused on the bioremediation capability of two bacterial species (Klebsiella planticola and Enterobacter cloacae) from the family Enterobacteriaceae. These bacteria have been identified as new species with capability of degrading methyl tertiary-butyl ether (MTBE). In order to enhance their degradation capability, selected concentrations and retention time were investigated. Methods: The bacteria were cultured on the nutrient agar (NA) medium at room temperature. pH of the medium was adjusted to 7. The medium was autoclaved at 121°C for 15 minutes and incubated for 24 hours at 35°C. After 24 hours, the mixture was inoculated into 50 mL of Luria Bertani (LB) liquid medium containing 50 and 150 ppm MTBE. The cultures were incubated for 2 and 5 days at 35°C and shacked on a shaker at 150 rpm. Cell concentrations of the bacteria in pure culture were determined from the optical density at 600 nm using a UV–VIS spectrophotometer. Then, the culture was centrifuged at 3800 rpm for 20 minutes. In the next step, the MTBE concentration in the supernatant was measured by gas chromatography/mass spectrometry (GC/MS, Agilent Technologies, 5975, US10304411, 5.02.07). Results: The results showed that both strains are able to grow in the presence of 50 and 150 ppm MTBE. In the best conditions, when cell density was 3×108 CFU/mL during 5 days, the highest rate of MTBE degradation for K. planticola and E. cloacae, was 43% and 40%, respectively. It was also revealed that Escherichia coli can degrade 50 and 150 ppm MTBE about 19.8% and 13.65%, respectively. Conclusion: It seems that E. coli can be a good candidate for MTBE degradation at high concentrations for a time longer than that in the present study. It was also found that the species have high performance at 50 ppm than 150 ppm. So, these bacteria can remove MTBE from the environment.

In 2015, phagraphene was introduced as a novel nanostructure, opening a new avenue in carbonaceous nanomaterial research. Herein, we investigated the potential application of phagraphene as a drug delivery system for anti-cancer adrucil, based on the density functional theory calculations. Results indicate that adrucil drug very weakly interacts with the phagraphene with adsorption energy about −2.9 kcal/mol. This makes the phagraphene inappropriate for the drug delivery. To overcome this problem, the phagraphene is doped with different impurity atoms including B, Al, and Si. It was found that the reactivity of the studied systems is as follows: Al-doped > Si-doped > B-doped > pristine phagraphene. Although doping of phagraphene with B atom increases the reactivity, the electronic properties of the B-doped phagraphene considerably change at the presence of the drug which makes it unsuitable for drug delivery. Also, the Al-doped phagraphene suffers from a large desorption time because of a large negative adsorption energy (−41.8 kcal/mol). Among the all systems, we predicted that Si-doped phagraphene is more appropriate for adrucil delivery because of a moderate adsorption energy (−14.0 kcal/mol), a short recovery time (0.02 s), and electronically harmless adsorption property.

We inspected the possibility of using a synthesized boron nitride nanocluster (B12N12) as a potential chemical sensor for anticancer α-cyano-4-hydroxycinnamic acid (CHC) drug by performing density functional theory calculations. It was found that CHC drug is mainly adsorbed via its acidic group on the BN nanocluster with adsorption energy about − 23.7 kcal/mol. In view of the high decrease of HOMO–LUMO energy gap (Eg) of the BN nanocluster after the adsorption process, it is expected that this process induces a significant increase in its electrical conductivity. Thus, the BN nanocluster is suggested as a potential sensor for CHC drug detection. We predicted that the BN cluster benefits from a short recovery time (~ 22.7 s) and high sensitivity (55.2% decrease in the Eg). Also, it is interesting that the BN nanocluster can be used as a sensor in the pristine form without needing to the functionalization, doping, decoration, etc. Finally, we showed that by increasing the percentage of Hartree–Fock exchange of the functional, the adsorption energy, and sensitivity are increased and decreased, respectively. Also, the sensitivity of the BN nanocluster is predicted to decrease in water solution.

2-((9H-fluoren-2-ylimino) methyl)phenol (F3) was synthesized by condensation reaction of 9H-fluoren-2-amine and 2-hydroxybenzaldehyde in EtOH and characterized by its melting point, 1H-,13C NMR and molecular mass. F3 exhibits a high selectivity for detection of Cr3 + and Al3 + ions as a fluorescent chemosensor and showed a single emission band at 536 nm upon excitation at 333 nm according to fluorescence emission studies. The addition of Cr3 + and Al3 + make a significant increase in fluorescent intensity at 536 nm in CH3CN, while other metal ions have almost no influence on the fluorescence. The fluorescence enhancement was attributed to the inhibited C N isomerization and the obstructed excited state intra-molecular proton transfer (ESIPT) of compound F3. Job's plot and DFT calculations data showed that the binding stoichiometries of F3 with Cr3 + and Al3 + are 2:1. The association constants (Ka) for Cr3 + and Al3 + were calculated and found to be 8.33 × 104 M− 1 and 5.44 × 104 M− 1, respectively. The detection limits were also calculated for Cr3 + and Al3 + and found to be 2.5 × 10− 7 mol/L and 3.1 × 10− 7 mol/L, respectively.

Cathinone (CT) is a psychoactive drug which its abuse is linked to several deaths worldwide. Here, we investigated the electronic response of BC 2 N nanotubes to the CT drug, using density functional theory calculations. Our results indicate that the CT drug is adsorbed on the pristine tube from its –NH 2 group with ad adsorption energy about −14.6 kcal/mol with no electronic response. To overcome this problem, we doped the tube with Al or Si atom. Both of the Al and Si dopants increase the tube sensitivity and strengthen the interaction. Our calculations demonstrate that despite the high sensitivity of the Al-doped BC 2 N nanotube to the CT drug, it suffers from a very long recovery time which makes it unsuitable for application in CT sensors. But the calculated recovery time for the Si-doped BC 2 N nanotube is predicted to be about 0.27 s , which is short and desirable. Also, we showed that the Si-doped tube can be used in the humidity condition and at the presence of some gases including H 2 , O 2 , N 2 , and CO 2 . It was concluded that Si-doped BC 2 N nanotubes may be promising candidate for application in the CT sensors which benefit form a short recovery time, high sensitivity, and selectivity.

Cathinone is an organic stimulant which is classified as psychoactive drug and its abuse has been linked to many deaths worldwide. Here, we studied the electronic sensitivity of a BN cage, a zigzag (6, 0) BN nanotube, and a BN nanosheet toward cathinone using density functional theory calculations. The B3LYP-D functional predicts that the order of magnitude of electrical conductivity of BN nanostructures is as follows tube > sheet > cage. The cathinone drug prefers to be adsorbed on the BN nanostructures via its NH2 group rather than O-head with adsorption energy about −16.1, −14.0 and −5.0 kcal/mol for cage, tube, and sheet, respectively. Our results indicate that by increasing the p-character of the hybridization of the adsorbing B atom in the BN nanostructures, the interaction is strengthened. Based on the density of states analysis, it was demonstrated that the electrical conductivity of the BN nanostructures is decreased by the drug adsorption, indicating that they can be used in the cathinone sensors. The order of magnitude of the sensitivity is as follows: SCage > STube > SSheet. This trend corresponds to the decrease of the structural curvature in the BN nanostructures. Finally, a short recovery time of about 0.54 s, 0.02 s and 4.4 ns is predicted for cage, tube and sheet, respectively, at 298 K.

We investigated the interaction of benzoylethanamine (BEA) drug with the AlN nanostructures including nanotube, nanocage, and nanosheet using density functional theory calculations. We predicted that the BEA molecule tends to be mainly adsorbed from its N-head on the Al atom of the AlN nanostructures with adsorption energy of − 66.0, − 126.2, and − 147.1 kJ/mol for nanosheet, nanotube, and nanocage, respectively. This indicates that by increasing the structural curvature, the interaction is strengthened. Also, it seems that by decreasing the structural curvature of the AlN nanostructures from nanocage to the nanosheet, the kinetic stability is increased which leads to an increase in the gap. When a BEA molecule is adsorbed on the AlN nanostructures, their electrical conductivity is increased, demonstrating that they can yield an electronic signal at the presence of this molecule and can be employed in chemical sensors. The order of magnitude of the sensitivity is as follows: S Nanosheet > S Nanotube > S Nanocage . We concluded that among the AlN nanostructures, the AlN nanosheet may be promising candidate for detection of BEA drug which benefits from a short recovery time of 0.33 s.

Using density functional theory calculations, we investigated the stability, solubility, structural, electronic, and optical properties of C30X15Y15 (X = B, and Al; Y = N, and P) heterofullerenes. The C30B15N15 is found to be the most stable heterofullerene with standard formation enthalpy (ΔH°f) of 222.2 kcal/mol, followed by C30Al15N15 (ΔH°f = 891.6 kcal/mol). The relative stability of fullerenes are as follows: BN > C60 > AlN ∼ BP > AlP, indicating that the BN doping makes the C60 more stable. The XY doping process significantly increases and decreases the solubility of C60 fullerene in water and benzene solvents, respectively. The standard Gibbs free energy of solvation (ΔG°solv) of C60 in water is increased from −0.7 to −33.5 kcal/mol by AlN doping process. The dopant X atoms are mainly contributed in generation of occupied states but the Y ones largely create the virtual states. Compared to the pristine C60, the electrical conductivity of the XY doped fullerenes are higher, and the order is as follows: AlP > BP > BN ∼ AlN >> C60. This indicates that the Al atoms destabilize and P ones stabilize the HOMO and LUMO levels, respectively. The optical gap of these fullerenes is smaller than the HOMO-LUMO gap by about 0.44–0.55 eV.

Magnetite nanoparticles (MNPs) have proved to be a useful support for heterogeneous catalysis. We have synthesized Fe3O4 MNPs functionalized with a copper(II) complex, and tested the resulting material as a heterogeneous nanocatalyst. The catalyst was tested for aldol condensation reactions between aliphatic/aromatic aldehydes and rhodanine or thiazolidine-2,4-dione (TZD) derivatives under reflux in ethanol, giving the target products in high yield. Environmentally benign chemistry, short reaction times, simple work-up, excellent yields, and the reusability of the new nanocatalyst are beneficial features of the present study. The nanocatalyst was characterized by scanning electron microscopy, vibrating sample magnetometery, thermogravimetry, X-ray diffraction, and energy-dispersive X-ray analyses. The data showed that the magnetic nanoparticles are super-paramagnetic with a size range of 10–20 nm.

Penetration of most of the polar drugs through the cell membrane is a challenging problem. It has been indicated that carbonaceous nanostructures can penetrate into biological cells. Here, we investigated the potential application of a C24 fullerene as a carrier for anti-cancer 5-fluorouracil (5-FU) drug using density functional theory calculations. It was found that the 5-FU interaction with the pristine fullerene is very weak with adsorption energy of about −3.2 kcal/mol which is not suitable for drug delivery. To overcome this problem, one carbon atom is substituted by a boron atom which increases the adsorption energy to −27.2 kcal/mol. The B-doping makes the electronic properties of the fullerene sensitive to the drug. Finally, we proposed a drug release based on the low pH in the cancer cells. It was indicated that attacking protons to the interaction area between the drug and fullerene separates the drug from the carrier.

The adsorption behavior and electronic sensitivity of the pristine, and Al-doped B24N24 (Al-BN) nanoclusters toward two carbonyl halides (F2CO, and Cl2CO (phosgene)) were investigated using density functional calculations. It was found that the carbonyl halides interact with the pristine cluster very weakly while by replacing a B atom of the cluster with an Al atom, the adsorption energy is significantly increased. The electronic properties of the pristine BN nanocluster are not sensitive to F2CO but after the Cl2CO adsorption, its HOMO-LUMO gap (E g) is significantly decreased. Despite this decrease, the BN cage is still insulator and cannot be used as a sensor. The Al-doping overcomes this problem by a primarily reduction in the E g (from 6.45 to 4.88 eV). Our calculations indicate that by F2CO and Cl2CO adsorptions, the Al-BN cluster is transformed from insulator to a semiconductor. This phenomenon largely increases the electrical conductivity of Al-BN and can produce electrical noise which is responsible for the gas detection. Also, it is shown that the Al-BN selectively responses to F2CO and Cl2CO gases.

N , N′ -bis(salicylidene)-2-(6-(2-aminophenyl)-4-phenylpyridin-2-yl) ( 3 ) was synthesized by condensation reaction of 2,6-bis(2-aminophenyl)-4-phenylpyridine and 2-hydroxybenzaldehyde in EtOH and characterized by its melting point, 1 H, 13 C NMR and molecular mass. The addition of Cr 3+ ion makes the significant increase of its fluorescent intensity at 537 nm in CH 3 CN/H 2 O (95/5%), however, other metal ions have almost no influence on the fluorescence. The reason for this phenomenon might be attributed to the formation of a 1:1 stoichiometric 3 -Cr 3+ complex which inhibits photo-induced electron transfer (PET) process. The 1:1 binding stoichiometry between 3 and Cr 3+ was established using Job’s plot, and the complex structure was proposed by DFT calculation. The association constant ( K a ) was determined to be 8.77 × 10 4 M −1 and the limit of detection (LOD) was calculated to be 2.2 × 10 −7 M.

Never agent identification and disposal is vital for both civilian and military defense resources. Herein, using density functional theory calculations, the reactivity and electronic sensitivity of pristine, Stone Wales (SW) defected, and Si-doped BN (Si-BN) nanosheets toward cyclosarin nerve agent were investigated. It was found that the interaction of cyclosarin with the pristine BN sheet is very weak and also that is not energetically favorable with SW defected one. Unlike the SW defect, replacing a B atom by Si atom significantly makes the cyclosarin adsorption energetically favorable. Calculations show that the carbonyl and etheric oxygen atoms of cyclosarin attack the Si atom of Si-BN with the adsorption energies of −73.5 and −136.9 kJ/mol, respectively. The cyclosarin nerve agent can be decomposed by the Si-BN sheet which is thermodynamically highly favorable. Upon this process, the HOMO and LUMO levels are significantly unstabilized and the HOMO-LUMO gap significantly changed by about 24.2%. The cyclosarin presence and its decomposition by Si-BN sheet can be recognized because of the electrical conductivity change of the sheet.

It has been recently indicated that the Li-ion batteries may be replaced by Na-ion batteries because of their low safety, high cost, and low-temperature performance, and lack of the Li mineral reserves. Here, using density functional theory calculations, we studied the potential application of B12N12 nanoclusters as anode in Na-ion batteries. Our calculations indicate that the adsorption energy of Na+ and Na are about -23.4 and -1.4kcal/mol, respectively, and the pristine BN cage to improve suffers from a low cell voltage (∼0.92V) as an anode in Na-ion batteries. We presented a strategy to increase the cell voltage and performance of Na-ion batteries. We showed that encapsulation of different halides (X=F-, Cl-, or Br-) into BN cage significantly increases the cell voltage. By increasing the atomic number of X, the Gibbs free energy change of cell becomes more negative and the cell voltage is increased up to 3.93V. The results are discussed based on the structural, energetic, frontier molecular orbital, charge transfer and electronic properties and compared with the performance of other nanostructured anodes.

This review article surveys literature methods for the carboxylative cyclization of N -propargylamines with CO 2 to provide 2-oxazolidinones. We have classified these reactions based on the type of catalysts.

Nanographenes are definite segments of graphene whose end atoms are saturated with hydrogens and their properties are different from those of the graphene because of size confinement. Herein, we investigated the structural properties, reactivity and electronic sensitivity of a newly synthesized borazine-like ring doped nanographene (BNG) to NO2 gas by means of density functional theory. We found that the central and peripheral rings of BNG are aromatic, while the middle ones are non-aromatic, revealing that this pattern follows the Clar’s sextet rule of aromaticity. Different thermodynamically stable NO2/BNG complexes are predicted, but most of them cannot be formed at room temperature because of the high transition barrier energies. The most favorable complex is that in which one oxygen atom of NO2 molecule is located above the center of B3N3 doped ring with adsorption energy of about −5.1 kcal/mol. It was found that the electronic properties of BNG are highly sensitive to the presence of NO2 molecules so that after the NO2 adsorption, the BNG is converted from a semiconductor to a semimetal compound. Thus, it was concluded that the BNG may be used in the NO2 sensor devices. Also, a short recovery time is predicted for the NO2 desorption process.

We studied the effect of Hartree-Fock (HF) exchange percentage of a density functional on the adsorption properties and electronic sensitivity of the B 12 N 12 nanocluster to CO molecule. It was found that by an increase in the %HF, the LUMO level is nearly constant while the HOMO level is strongly stabilized, expanding the HOMO-LUMO gap (E g ). Also, the volume of the all structures decreased and the sensitivity of the B 12 N 12 is slightly increased to CO molecule. For the pristine B 12 N 12 cluster, the B66 and B64 bonds are about 1.43 and 1.49 A at 10% HF, and 1.23 and 1.26 A at 100% HF, respectively. The HF exchange between 10–20% may predict an accurate E g for the B 12 N 12 system. We concluded that functionals with a large %HF such as M06-HF, and M06-2X may significantly overestimate the E g , and bond strength. We obtained a parabolic relationship between the %HF and the adsorption energy of CO molecule on the B 12 N 12 cluster. Also, an increase in the %HF predicts a larger charge transfer from the CO molecule to the cage.

Detection of illicit drugs is of increasing interest for police and drug communities because of their abuse. Using density functional calculations, we investigated the interaction of amphetamine (AA) drug with the pristine, B, Al, Ga (group IIIA), Si, and Ge (IIV group) doped C60 fullerenes. The AA cycloaddition from its phenyl ring to the [6–6] bonds of C60 is more favorable than that to the [5–6] bonds, in good agreement with experiment. When an AA molecule is adsorbed from its –NH2 group on the C60 fullerene, its work function is significantly decreased, showing a good sensitivity but the adsorption energy (−0.4 kcal/mol) is very small. Replacing a carbon atom of C60 by the impurity atoms, the interaction between the AA and the C60 is largely improved (adsorption energy ∼ −38.6 to −65.6 kcal/mol). Upon the adsorption of AA on the doped fullerenes, the Fermi level is largely shifted to higher energy, especially in the case of Si and Ge-doped fullerenes, and thus, the work function decreases by about 22.7 and 24.9%, respectively. The electron emission largely increases which can be converted to an electronic noise. However, the Si and Ge-C60 fullerenes are work function-type sensors for AA drug.

We investigated the reactivity and sensitivity of pristine, and Al-doped boron nitride (Al-BN) nanosheets to nerve agents including cyclosarin (GF) and tabun (GA) by means of density functional calculations. A weak interaction is predicted for both GF and GA with the pristine BN sheet with adsorption energies of − 12.0 and − 10.9 kcal/mol, respectively. Calculations show that the carbonyl oxygen atom of both GF and GA are the most nucleophile active site. The electronic sensitivity of the BN nanosheet is predicted to be negligible to these nerve agents. To overcome this problem, we have replaced a B atom of the sheet by an Al atom and investigated the adsorption process. It was found that the reactivity of the sheet in significantly increased to these agents after the Al-doping while the electronic sensitivity is improved only for GA gas. By adsorbing the GA on the Al-BN, its electrical conductivity is largely increased because of a decrease about 32.6% in the HOMO-LUMO energy gap. We have concluded that the Al-doping process helps the BN sheet to detect the GA gas and may be used in its sensor devices.

The electronic, optical, energetic, and structural properties of a HBC (hexa-peri-hexabenzocoronene) nanographene and its central benzene- and coronene-like BN substituted forms, and also full BN analogue were investigated using density functional theory. It was found that a larger number of carbon atoms cause a more negative cohesive energy and, thereby a greater structural stability. Our nucleus independent chemical shift analysis indicates that the aromaticity and Clar’s sextet rule determine the relative stability of these structures. The benzene-like or coronene-like doping makes the HBC more insulator or semiconductor. Electron-hole Frenkel type exciton binding energy was predicted and calculated to be nearly identical for all nanographenes in the range of 0.61–0.69 eV. The coronene-like BN-doped HBC (BN2-HBN) shows higher conductivity due to very narrow optical and HOMO-LUMO energy gap. Partial density of states analysis indicates that the BN2-HBC electronically can be assumed a full BN whose peripheral atoms are replaced by carbon atoms. These carbon atoms are responsible for new states which are appeared within the gap.

Imidazole and its derivatives are privileged N-heterocyclic structures present in various natural products and synthetic pharmaceuticals. Despite the numerous methods that have been developed for the synthesis of imidazole cores, it is still challenging to readily achieve high efficiency and regioselectivity in imidazole synthesis. Therefore, synthesis of these compounds using new protocols is always interesting. In this study we discuss the most representative and interesting reports on the synthesis of imidazoles and their fused analogues from N-propargylamines. Mechanistic aspects of the reactions are considered and discussed in detail.

3-Methyleneindolinone derivatives are important structural motifs found in many compounds of natural occurrence and pharmacological significance. However, despite their wide importance, mild and highly efficient stereoselective synthesis of (E)- and (Z)-3-methyleneindolinones still remains to be a difficult problem. Therefore, the development of new synthetic methods for their stereocontrolled preparation is of prime importance in organic synthesis. In this mini review, we highlight the advances in stereoselective synthesis of mono- and disubstituted-3-methyleneindolinones through metal-catalyzed intramolecular cyclization of N-arylpropiolamides from 1988 to 2017.

The interesting features in the lithium based electride motived us to explore new species with electride properties. To achieve this goal, the tetracyano-2,6-naphthoquinodimethane (TNAP) species has been used as backbone to investigate systematic addition of lithium atoms to the TNAP backbone (Lin@TNAP (n = 1–4) species) through density functional theory (DFT) simulation. After finding the most stable geometries for each Lin@TNAP (n = 1–4) species by full optimization process, we show their electronic-structural features in this work. In the next step, the properties of electron-density-laplacian (∇2ρ(r)), non-linear-optical (NLO), non-nuclear-attractor (NNA), and electron-localization-function (ELF) have been studied to incorporate the reported Lin@TNAP (n = 1–4) species in two different categories, salt or electride. The obtained outcomes present that the Li1@TNAP and the Li2@TNAP molecules are the lithium-salt. In contrast, the Li3@TNAP and the Li4@TNAP molecules are lithium-based electrides along with the isolated electrons in the molecular structure.

Aim and Objective: The magic scaffolds rhodanine and thiazolidine are very important heterocyclic compounds in drug design and discovery. Those are important heterocyclic compounds that have attracted a great deal of attention due to the fact that they exhibit a variety of bioactivities including antibacterial, antifungal, antiviral, antimalarial, and anti-inflammatory activities. These agents often exhibit selective toxicity. The goal of this study was molecular docking, green and solvent-free efficient synthesis of a new series of hetero/aromatic substituted rhodanine and thiazolidine analogues and then investigation of their antimicrobial activity. Materials and Methods: To a mixture of TZD or rhodanine (1 mmol) in the presence of ionic liquid ChCl/urea, various aldehyde (1 mmol) was added. After completion of the reaction, obtained crude compound was collected by filtration and products were recrystallized from ethanol. The binding-free energy between all synthesized compounds with 3EEJ protein (C. glabrata enzyme) were obtained by molecular docking studies. These compounds were evaluated using microdilution method against (ATCC 6538) and (ATCC 12228) Gram-negative, (ATCC 8739) and (ATCC 9027) as Gram-positive and (ATCC 1012), (ATCC 339), C. (ATCC 1057), (ATCC 503), (ATCC 340) and (ATCC 194) as fungi. Results: All of the acceptable products were determined by 1H NMR, 13C NMR, Mas and FT-IR spectroscopy. The binding-free energy between compounds 10a and 10b with 3EEJ protein were found to be -8.08 kcal/mol and -8.15 kcal/mol, respectively. These compounds having a heteroaromatic ring attached to the TZD or rhodanine core showed excellent antimicrobial activity with MIC values of 0.25-8 μg/mL (compound 10a) and 0.5-16 μg/mL (compound 10b) against the most tested fungi strains, Gram-positive and Gram-negative bacteria. Conclusion: A convenient and rapid method has been developed for the synthesis of rhodanine and thiazolidine-2,4-dione (TZD) derivatives as efficient antimicrobial agents using a Deep Eutectic Ionic Liquids (DEILs) choline chloride urea under solvent-free condition. Among the newly synthesized compounds, (Z)-5-((quinoxalin-3-yl) methylene) thiazolidine-2, 4-dione (10a) and (Z)- 5- ((quinoxalin-3-yl) methylene)-2-thioxothiazolidin-one (10b) exerted the promising effect and these compounds can be considered to be further probed as inhibitors of cgDHFR enzyme.

Supplementary Methods

Supplementary Methods

Supplementary Western Blots

In this work, the interaction of an aspirin (AS) molecule with the external surface of a boron nitride fullerene-like nanocage (B12N12) is studied by means of density functional theory (DFT) calculations. Equilibrium geometry, electronic properties, adsorption energy and thermodynamic stability are identified for all of the adsorbed configurations. Four stable configurations are obtained for the interaction of AS molecule with the B12N12 nanocage, with adsorption energies in the range of −10.1 to −37.7 kcal/mol (at the M06-2X/6-31 + G** level). Our results clearly indicate that Al-doping of the B12N12 tends to increase the adsorption energy and thermodynamic stability of AS molecule over this nanocage. We further study the adsorption of AS over the B12N12 and B11N12Al in the presence of a protic (water) or aprotic (benzene) solvent. It is found that the calculated binding distances and adsorption energies by the PCM and CPCM solvent models are very similar, especially for the B12N12 complexes. According to time-dependent DFT calculations, the Al-doping can shift estimated λ max values toward longer wavelengths (redshift). Solvent effects also have an important influence on the calculated electronic absorption spectra of AS-B12N12 complexes.