Exploring nonlinear optical properties in a hybrid dihydrogen phosphate system: an experimental and theoretical approach

CONTEXT

The controlled slow evaporation process conducted at room temperature has produced a novel hybrid material denoted as (2-hydroxyethyl) trimethylammonium dihydrogen phosphate [2-HDETDHP] (C5H14NO+, H2PO4-), synthesized through the solution growth method. X-ray crystallography analysis reveals a triclinic structure with a filling rate of P and a Z value of 2. This hybrid material displays noteworthy absorption characteristics in the middle and far ultraviolet regions. UV-visible spectroscopy further establishes its transparency in the visible and near-visible ultraviolet domains. FT-IR spectroscopy examines various vibration modes, elucidating their relationships with the functional groups within the structure. Two- and three-dimensional fingerprint maps, coupled with three-dimensional crystal structures through Hirshfeld Surface Analysis, unveil the dominance of O•••H and H•••H interactions in the structure, comprising 49.40% and 50.40%, respectively. Fingerprint plots derived from the Hirshfeld surface assess the percentages of hydrogen bonding interactions, with 80.6% attributed to a fragment patch. The experiment of antimicrobial efficacy of a synthesized product, conducted in triplicate, demonstrated the synthesized product's potential antimicrobial activity.

METHODS

Hirshfeld surfaces are employed to investigate intermolecular hydrogen bonding, specifically within single phosphate groups. The molecular structure of 2-HDETDHP was refined using single-crystal X-ray analysis, while its optical characteristics were examined through UV-visible spectroscopy. FT-IR spectroscopy is employed for the assignment of molecular vibrations of functional groups in the affined structure. Quantum calculations were executed with the GAUSSIAN 09 software package at B3LYP/6-311G level of theory, to optimize the molecular geometries. The antimicrobial efficacy of a synthesized product was evaluated using the disc diffusion method against antibiotic-resistant Candida albicans, Candida tropicalis, Aspergillus niger, Staphylococcus aureus, and Escherichia coli. Microorganisms were cultured on nutrient agar, and inhibition zones were measured after incubation, with streptomycin and amphotericin as positive controls.

ADME Study, Molecular Docking, Elucidating the Selectivities and the Mechanism of [4 + 2] Cycloaddition Reaction Between (E)-N ((dimethylamino)methylene)benzothioamide and (S)-3-acryloyl-4-phenyloxazolidin-2-one

The molecular electron density theory (MEDT) was employed to examine the [4 + 2] cycloaddition reaction between (E)-N-((dimethylamino)methylene)benzothioamide (1) and (S)-3-acryloyl-4-phenyloxazolidin-2-one (2) at the B3LYP/6-311++G(d,p) design level. Parr functions and energy studies clearly show that this reaction is regio- and stereoselective, in perfect agreement with experimental results. By evaluating the chemical mechanism in terms of bond evolution theory (BET) and electron localization function (ELF), which divulges a variety of variations in the electron density along the reaction path, a single-step mechanism with highly asynchronous transition states structures was revealed. Additionally, we conducted a docking study on compounds P1, P2, P3, and P4 in the SARS-CoV-2 main protease (6LU7) in comparison to Nirmatrelvir. Our findings provide confirmation that product P4 may serve as a potent antiviral drug.

Chromatography Scrutiny, Molecular Docking, Clarifying the Selectivities and the Mechanism of [3 + 2] Cycloloaddition Reaction between Linallol and Chlorobenzene-Nitrile-oxide

Employing the Molecular Electron Density Theory, [3 + 2] cycloaddition processes between 4-chlorobenzenenitrileoxide and linalool, have been applied using the DFT/B3LYP/6-311(d,p) method, activation, reaction energies and the reactivity indices are calculated. In an investigation of conceptual DFT indices, LIL-1 will contribute to this reaction as a nucleophile, whilst NOX-2 will participate as an electrophile. This cyclization is regio, chemo and stereospecific, as demonstrated by the reaction and activation energies, in clear agreement with the experiment's results, in addition, ELF analysis revealed that the mechanism for this cycloaddition occurs in two steps. Furthermore, a docking study was conducted on the products studied, and the interaction with the protein protease COVID-19 (PDB ID: 6LU7), our results indicate that the presence of the -OH group increases the affinity of these products, moreover, adsorption study by chromatography was made on silica gel as support; our outcome reveals that the -OH group creates an intramolecular hydrogen bond in the product P2, while in the product P3 will create a hydrogen bond with the silica gel which makes the two products P2 and P3 are very easy to separate by chromatography, this result is in excellent agreement with the Rf retention value. The study might provide a fundamental for developing natural anti-viral compound in promoting human health.

Explaining the selectivities and the mechanism of [3+2] cycloloaddition reaction between isoalantolactone and diazocyclopropane

CONTEXT

[3+2] cycloaddition processes between isoalantolactone (ISALL) and diazocyclopropane (DCYP), have been surveyed exercising the MEDT, reactivity indices, reactions, and activation energies, are computed. In an investigation of conceptual DFT indices, DCYP behaves as a nucleophile in this reaction, whereas ISALL acts as an electrophile. This cyclization is stereo-, chemo-, and regiospecific, as demonstrated by the activation and reaction energies, in clear agreement with the experiment's results. The mechanism for this [3+2] cycloaddition is occurring in two steps, according to ELF analysis.

METHODS

For the purposes of this investigation, all computations were performed using the Gaussian 09 program. The optimization was completed using Berny's computational gradient optimization approach with the basis set 6-311G(d,p) and wB97XD functional. Frequency computations were utilized to characterize and locate stationary points where the transition phases have just one imaginary frequency and all frequencies for the reactants and products are positive. After evaluating the effect of dichloromethane (DCM) as a reaction solvent, the stationary point optimization was updated using the polarizable continuum model (PCM) developed by the Tomasi team. The electron localization function (ELF) has been examined within the context of topological investigations using Multiwfn software with a 0.05 grid step.

Chemical reactivities and molecular docking studies of parthenolide with the main protease of HEP-G2 and SARS-CoV-2

We have used bioinformatics to identify drugs for the treatment of COVID-19, using drugs already being tested for the treatment as benchmarks like Remdesivir and Chloroquine. Our findings provide further support for drugs that are already being explored as therapeutic agents for the treatment of COVID-19 and identify promising new targets that merit further investigation. In addition, the epoxidation of Parthenolide 1 using peracids, has been scrutinized within the MEDT at the B3LYP/6-311(d,p) computational level. DFT results showed a high chemoselectivity on the double bond C₃[bond, double bond]C₄, in full agreement with the experimental outcomes. ELF analysis demonstrated that epoxidation reaction took place through a one-step mechanism, in which the formation of the two new C-O single bonds is somewhat asynchronous.

Corrosion inhibition performance of azelaic acid dihydrazide: a molecular dynamics and Monte Carlo simulation study

The adsorption of azelaic acid dihydrazide as an environmentally friendly mild steel corrosion inhibitor on the iron surface was modeled in this study. We used density functional theory (DFT) calculations and Monte Carlo (MC) and molecular dynamics (MD) simulations to illustrate the interactions engaged. The interaction of the azelaic acid derivatives with iron metal (Fe) was examined by DFT as a typical example of a corrosion prevention mechanism after the optimized molecular structures of these molecules were investigated. Structures, binding energies, Fikui's charge indicator, electron transfer, and chemical potential are all discussed. The presence of significant binding between the inhibitor and Fe metal is supported by analysis of the resultant complex. Then, in an acidic solution comprising 491 H₂O, nine chlorine ion Cl^-, and nine hydronium ion H₃O⁺, molecular dynamics and Monte Carlo (MC) simulation were used to model the adsorption of azelaic acid dihydrazide on the iron Fe (110) surface. In addition, radial distribution function (RDF) and interaction energy (Ei) were evaluated in this work to further our understanding of interactions between azelaic acid dihydrazide and iron surfaces. Furthermore, we discovered that our inhibitors have an excellent ability to slow down the movement of corrosive particles in law temperature and thus to inhibit the metallic substrate against corrosive electrolyte, based on the temperature impact investigation. The result of density functional theory and Monte Carlo and molecular dynamics descriptors obtained were in good agreement with the experimental result.

Theoretical study of the chemical reactivity of a class of trivalent phosphorus derivatives towards polyhaloalkanes: DFT study

In the current work, the chemical reactivity of some trivalent phosphorus derivatives R₂PR^' towards polyhaloalkanes CCl₃POR ' '₂ was studied by the quantum method DFT/B3LYP/6-311G(d,p). The introduction of substituents for the trivalent phosphorus derivative and polyhaloalkane allowed us to have more information on these reactions. On the one hand, the calculation of reactivity indices derived from the DFT/B3LYP/6-311G(d,p) method and the gap_{LUMO - HOMO} show that trivalent organophosphorus derivatives behave as nucleophiles, while polyhaloalkanes act as electrophiles. On the other hand, the calculation of the activation barrier and the determination of the free enthalpy variation prove that the kinetic and thermodynamic products of these reactions result from the nucleophilic attack of the phosphorus atom on the chlorine halogen. All these theoretical predictions are in very good agreement with the experimental results.

A molecular electron density theory study for [3+2] cycloaddition reactions of N-benzylcyclohexylnitrone with methyl-3-butenoate

The [3+2] cycloaddition (32CA) reactions of N-benzylcyclohexylnitrone 1 with methyl-3-butenoate 2 have been studied within molecular electron density theory (MEDT) at the B3LYP/6-311++G(d,p) level of theory.

MEDT study of the 1,3-DC reaction of diazomethane with Psilostachyin and investigation about the interactions of some pyrazoline derivatives with protease (Mpro) of nCoV-2

The molecular electronic density theory (MEDT) was invested to elucidate the chemo-, regio- and stereo-selectivity of the 1,3-dipolar cycloaddition between Diazomethane (DZM) and Psilostachyin (PSH). The DFT method at B3LYP/6-31 + G (d,p) level of theory was used. Reactivity indices, transition structures theory, IGM and ELF analysis were employed to reveal the mechanism of the reaction. The addition of DZM to PSH takes place through a one-step mechanism and an asynchronous transition states. Eight possible addition channels of reaction were investigated (addition of C (sp2) to Diazomethane at C4, C5, C6 or C7). The addition of C (sp2) at C5 leading to P1 product is the preferred channel. The addition of ether does not affect the chemo-, regio- and stereo-selectivity of the reaction. Analysis of transfer of charges along the IRC path associated with the P1 product shows a polar character for the studied reaction. We have also used the noncovalent interaction (NCI) which is very helpful to reveal the most favored addition channel of the reaction, by analyzing the weak interactions in different TSs. Finally, we investigate about the potential of inhibition of some pyrazoline compounds against COVID-19-M^pro by performing a molecular docking calculations.

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The 1,3-DC reaction between Diazomethane and Psilostachyin has been investigated by MEDT.

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The asynchronicity of TSs has been revealed by IGM and Wiberg indices.

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The electronic description of mechanism of reaction has been performed by ELF analysis.

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The NCI analysis allow a deep description of weak interactions.

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The pyrazolines products possess a potential effect against COVID-19.

Theoretical study of the 1,3-DC reaction between fluorinated alkynes and azides: Reactivity indices, transition structures, IGM and ELF analysis

DFT/B3LYP/6-31 + g(d,p) calculations were performed and reactivity indices, transition structures theory were applied to elucidate the molecular mechanism of the reaction between fluorinated alkynes and different azides. The process of cycloaddition operates through a one-step mechanism and an asynchronous transition states. Examination of the energy profile in the gas phase show two possible 1,4 and 1,5 addition channels for amid, the former is preferred. Furthermore, the Parr functions have used to elucidate the reaction's regioselectivity. It was noted that the addition of solvent (DMSO) does not affect the regioselectivity of the reactions. Analysis of charge transfer in the transition structures shows a moderate polar character for the majority of the studied reactions. Moreover, the independent gradient model based on promolecular density (IGM) has been used to evaluate the asynchronicity of the formation of the two new sigma bonds. Finally, the ELF calculation has been performed to clearly describe the formation of the previous bonds along the IRC path.

A molecular electron density theory study of the mechanism, chemo- and stereoselectivity of the epoxidation reaction of R-carvone with peracetic acid

The epoxidation reaction of R-carvone 8 with peracetic acid 9 has been studied within the molecular electron density theory at the B3LYP/6-311(d,p) computational level.

A New Monoterpene Isolated from Nigella sativa Essential Oil

A new monoterpene 2-allyl-1,4-dihydroxy-5-methylbenzene 1 has been isolated from the essential oil of Nigella sativa seeds along with five known compounds including thymoquinone, carvacrol, dihydrothymoquinone, terpinen-4-ol and dithymoquinone. The structure of the new monoterpene 1 was elucidated using 1D and 2D NMR studies.

Theoretical study of stereoselectivity of the [1 + 2] cycloaddition reaction between (1S,3R,8S)-2,2-dichloro-3,7,7,10-tetramethyltricyclo[6,4,0,0(1.3)]dodec-9-ene and dibromocarbene using density functional theory (DFT) B3LYP/6-31G*(d)

In this work we used density functional theory (DFT) B3LYP/6-31G*(d) to study the stoichiometric reaction between the product (1S,3R,8S)-2,2-dichloro-3,7,7,10-tetramethyltricyclo[6,4,0,0(1.3)]dodec-9-ene (referred to here as P1) and dibromocarbene. We have shown that P1 behaves as a nucleophile, while dibromocarbene behaves as an electrophile; that the chemical potential of dibromocarbene is superior to that of P1 in absolute terms; and that P1 reacts with an equivalent quantity of dibromocarbene to produce two products: (1S,3R,8R,9S,11R)-10,10-dibromo-2,2-dichloro-3,7,7,11-tetramethyltetracyclo[6,5,0,0(1.3),0(9.11)] tridecane (referred to here as P2) and (1S,3R,8R,9R,11S)-10,10-dibromo-2,2-dichloro-3,7,7,11-tetramethyltetracyclo[6,5,0,0(1.3),0(9.11)] tridecane (referred to here as P3). P2 and P3 are formed at the α and β sides, respectively, of the C2 = C3 double bond of P1. This reaction is exothermic, stereoselective and chemospecific, and is controlled by charge transfer. Regioselectivity of the reaction was interpreted using the Lee-Yang-Parr functional.

[Cutaneous leishmaniasis in the military hospital Moulay Ismaïl of Meknes (Morocco): about 49 cases diagnosed between 2005 and 2011]

An increase in the number of cases of cutaneous leishmaniasis has been observed, in recent years, in Morocco. We tried, through a series of 49 cases collected from the dermatology department at the military hospital Moulay Ismail of Meknes, to clarify the epidemiological, clinical and evolutionary aspects of the reported cases. We recorded for each patient: age, sex, geographic origin and the period before consultation. We have also noted the number of lesions, their location, and their clinical aspects. Finally, we recorded results of direct examination in search of the parasite, treatment and post treatment evolution. The sex ratio was 11. The average age was 35.6 years. The average period of consultation was 3.8 months. Eighty-six percent of cases (n=42) were from the region extending from south to south-east of the atlas. The average number of lesions per patient was 4.46 (from 1 to 40). Thirty-seven percent of cases (n=18) had single lesions and 63% (n=31) multiple lesions. There was a polymorphism of clinical aspects of lesions with predominant of ulcerative crusting aspects observed in 55.1% of cases (n=27). Face localization was observed in 20.4% of cases (n=10). Ninety-two percent of cases (n=45) had involvement of the upper limbs and/or lower. Direct examination was positive in 65% of cases (n=32). The treatment was based on meglumine antimoniate associated in three quarters of cases with cryotherapy using liquid nitrogen. The outcome was favorable for all patients. We observed an increase in the number of cases in 2011 and especially those with multiple lesions followed by a decline in 2011.

(4aS,10aS)-7-Hydr-oxy-8-isopropyl-1,1,4a-trimethyl-1,2,3,4,4a,9,10,10a-octa-hydro-phenanthrene: a new diterpenoid compound

The new title diterpenoid compound, C₂₀H₃₀O, is a natural product isolated from Tetra­clinis articulata wood via chloro­form extraction. The asymmetric unit contains four mol­ecules with the same S,S configuration, deduced from the chemical synthesis. Indeed, an overlay analysis, calculated using structure-matching software, shows that the four mol­ecules can be superimposed. The central ring has a half-chair conformation, whereas the saturated ring displays a chair conformation.