First-order Hyperpolarizability Research Articles

DFT study of the intrinsic electronic, optical, NBO, transport, and thermodynamic properties of 12,12-dimethyl-7-phenyl-7,12-dihydrobenzo[a]acridine-3-carbonitrile (BACN)

In this study, we investigate the structural, vibrational, electronic, optical, transport, and thermodynamic properties of pure BACN using density functional theory (DFT). The B3LYP, B3PW91, CAM-B3LYP and ωB97XD functionals associated with the basis sets 6-31G(d,p) and 6-311G(d,p) were used. With regard to the electronic and transport properties, analysis of the HOMO and LUMO frontier orbitals, the gap values obtained and the reorganisation energies show that BACN is a good donor-acceptor semiconductor and has a good hole transport capacity. The study of non-linear optical properties shows that BACN is a good candidate for applications in nonlinear optics (NLO) because of its first-order hyperpolarisability, which is higher than that of urea. The time density functional theory (TD-DFT) approach was used for the photophysical analysis of BACN. It was found that BACN exhibits a maximum absorption in the near-UV range, peaking at 222.42 nm, and strong emission in the near-UV range with a maximum wavelength value of 229.75 nm through TD-CAM-B3LYP/6-311G(d,p). The Stokes shift values obtained indicate that the molecule is chemically stable. The full width at half-maximum (FWHM) and radiative lifetime values for this molecule are 19.924 nm and 16.071 ns, respectively. These results show that BACN is a fluorescent material that can be used as an emitter material for designing and improving the colour purity of organic light-emitting diodes (OLEDs).

Synthesis, Theoretical studies, and antibacterial activity of Novel Zn(II) metal complex with salicylaldehyde semicarbazone, and ortho phenylene diamine ligands.

Computational and experimental investigation of synthesized Zn(II) complex. Salicylaldehyde semicarbazone (SSC) and ortho phenylene diamine (OPDA) were the ligands for the preparation of Zn(II) metal complex. Using quantum chemistry simulations at DFT/B3LYP/LANL2DZ level of theory. FT-IR, UV, and Mass spectrometry methods were characterized the complex. The computed small gap energy demonstrated that the Zn(II) molecule had good biological activity. Measured dipole moment and first-order hyperpolarizability values were useful to investigate the complex NLO activity. Intra-molecular charge transfer, donor-acceptor transitions, and stabilization energies were determined by analyzing natural bond orbital (NBO) and Mulliken charges. Electrophilic and nucleophilic interactions were performed with the MEP map. QTAIM framework explained the nature of different intermolecular interactions within the molecule. Moreover, the ADMET studies of Zn(II) compound were also analyzed. The title molecule showed good antibacterial activity.

Linear and nonlinear properties of Violerythrin and the quinoid carotenoid isorenieratene-3,3′-dione

This study investigates the optical properties and first-order hyperpolarizability of Violerythrin (SV) and quinoid carotenoid isorenieratene-3,3′-dione (IRD) structures, prominent natural nonlinear materials, using DFT and TD-DFT methods. Employing B3LYP and CAM-B3LYP functionals with a 6–311++G (d, p) basis set, calculations are conducted in both gas and acetone environments. Results show IRD's preference due to its closer alignment with experimental values and its red-shifted absorption compared to SV. In acetone, reductions in HOMO-LUMO energy gaps and increases in electrophilicity index suggest potential electron transfer with low band gap molecules. Higher dipole moments in acetone indicate increased charge transfer due to solvation. IRD exhibits superior nonlinear optical characteristics compared to SV in both acetone and gas phases, highlighting avenues for further experimental exploration.

Effect of spirocyclization of xanthene dyes on linear and nonlinear optical properties by considering D-π-A and D-A-D Systems: DFT and TD-DFT approach

Spirocyclization, a unique feature of xanthene dyes, makes it a promising candidate for developing fluorescent ratiometric probes for sensing, imaging, tracking, and labeling. How will this feature of xanthene dyes influence the linear and nonlinear optical properties? To examine the effect of spirocyclization of xanthene dyes, we have selected both the open-close form of rhodamine B and π-extended xanthene dyes substituted with thienyl and thieno[3,2-b]thienyl group at position 3 and 6. Here, rhodamine B will serve as the (Donor)D-π-A(Acceptor) system and thiophene-substituted xanthene dyes will serve as the D-A-D system. The geometry optimization of the close-open form of xanthene dyes at B3LYP/6–311++G(d,p) and CAM-B3LYP/6–311++G(d,p) revealed that the open form is energetically more stable in the S0 state than the closed form. The vertical excitation energy (ΔE), from Time-Dependent-Density Functional Theory (TD-DFT) calculation at B3LYP/6–311++G(d,p), CAM-B3LYP/6–311++G(d,p), ωB97XD/6–311++G(d,p) revealed that (ΔE)open < (ΔE)close. Further, the open form of xanthene dyes displays red-shifted absorption compared to the closed form. The λVt of xanthene dyes (open-close forms) is mainly assigned to HOMO → LUMO transition (S0 → S1) with % orbital contribution for open form ∼ 90 % and close form ∼ 60 %. The oscillator strength of xanthene dyes is obtained in the range of 0.01 – 1.74. The λVt of xanthene dyes is in agreement with experimental absorption. The static polarizability (α0), first-order hyperpolarizability (β0), second-order hyperpolarizability (γ), molecular hyperpolarizability (µβ0), and frequency-dependent hyperpolarizability (β1064), of the open form of xanthene dyes, were found to be higher than the close form. Thus, the open form of xanthene dyes will show superior linear and nonlinear optical properties than the closed form. The thienyl[3, 2-b] thieno substituted xanthene dye with red-shifted absorption shows higher α0, β0, γ, µβ0, β1064, and γ values, show better linear and NLO properties than thienyl and diethylamine substituted xanthene dyes.

Pseudo-Stilbene- and Azobenzene-Type Systems for Optical Frequency Conversion: Estimating the First-Order Molecular Hyperpolarizability

This study investigates the potential of a set of pseudo-stilbene and azobenzene molecular structures to become optical frequency converters for optical communications based on a detailed exploration of the first-order molecular hyperpolarizability (βHRS), which is the microscopic counterpart of second harmonic generation (SHG). βHRS values were obtained via quantum chemical calculations using the Gaussian 16 software package in solvent and gas-phase media at different wavelengths, i.e., 1064 nm, 1310 nm, and 1510 nm. The latter two wavelengths are of particular interest for optical communications. Our study focused on discerning how the molecular structure influences the βHRS response, explicitly highlighting the influence of the azomethine group (CH=N). The results revealed that the molecular planarity, affected by this group, plays a crucial role in modulating the optical properties. The highest βHRS value in a solvent medium using the CAM-B3LYP/6-311+G(2d,p) level of theory achieved in this work was around 1400 ×10−30cm4startvolt−1, four orders of magnitude higher than KDP (0.2 ×10−30cm4startvolt−1), which is a reference in SHG experiments at 1064 nm. The highest calculated βHRS value at the same level of theory and solvent at 1310 nm and 1550 nm was 631 × 10−30cm4startvolt−1 and 456 × 10−30cm4startvolt−1, respectively. All these values belong to molecular structures with azo-coupling with donor (4-NMe2) and acceptor (4′-NO2) peripheral groups, designated as AB-3.

Single crystal of barium bis para-nitrophenolate para-nitrophenol tetrahydrate for NLO applications: crystal growth and DFT analysis

Abstract Single crystals of barium bis para-Nitrophenolate para-Nitrophenol tetrahydrate (BBPNT) were grown via the slow evaporation technique. The crystal dimensions were measured to be 15 mm × 10 mm × 6 mm. The BBPNT crystal was analyzed using X-ray diffraction, FTIR spectrum, UV–vis spectrum, dielectric studies, thermo-gravimetric (TG) differential thermal analyses (DTA), Vickers microhardness test, second-harmonic generation efficiency, Z-scan technique, PL spectra, and laser damage threshold studies. These findings were previously published in our paper. In the current situation, the theoretical methods include analyzing several aspects, such as the molecular structure determined using X-ray experimentation at its lowest energy state. This analysis is then contrasted by means of density functional theory (DFT) with a suitable set of basic functions. The first-order hyperpolarizability may also be determined via the use of Density Functional Theory (DFT) methods. The molecule’s stability, resulting from hyper conjugative interactions, was examined using the natural bond orbital approach to analyses its nonlinear optical activity and charge delocalization. The magnitude of the HOMO–LUMO energy gap indicates the potential for charge transfer inside the molecule. The investigation of donor-acceptor interactions was conducted using NBO analysis based on optimized ground state geometries.

Slow evaporation synthesis, crystal structure, DFT calculations, molecular docking, and pharmacokinetic studies of hexaaquazinc(II) dihydrogen benzene-1,2,4,5-tetracarboxylate

A new complex formed from the reaction of benzene-1,2,4,5-tetracarboxylic dianhydride with zinc(II) acetate dihydrate was synthesized and characterized by single-crystal X-ray diffraction, thermal analysis (TGA), and density functional theory (DFT). [C10H4O8][Zn(H2O)6] (1), crystallized in a monoclinic system with space group P2/m. Theoretical modeling was performed at the DFT/B3LYP computational level with 6–311 G(d,p) and LanL2DZ basis sets. The Zn(II) is six-coordinate, forming an ideal octahedral geometry. A Hirshfeld surface analysis of the complex indicated that H···O/O···H contacts contribute to 47.8% of the crystal packing. The stability of 1 was investigated by determining the global chemical reactivity descriptors (GCRD). The nonlinear optical (NLO) behavior was investigated by analyzing the dipole moment, polarizability, and first-order hyperpolarizability (μ, α and β) via a theoretical approach, indicating that 1 has important nonlinear optical properties. A molecular docking study shows binding of 1 on the active site of receptors from human cyclooxygenase-2 enzyme (PDB code: 5IKT) and Escherichia coli MenB (PDB code: 3T88).

Li+(3)Mg−: A new alkaline earthide with large nonlinear optical response

Alkali metal doping has been identified as a vital step in facilitating an increase in the first hyperpolarizability(β0). To further explore this concept, we utilized Calix (Zhang et al., 2018) [3]pyrrole (3), Calix (Ma et al., 2017) [4]pyrrole (4), and Calix (Aloraini et al., 2022) [5]pyrrole (5) as our three ligands in this study. The choice of these ligands was based on their ability to undergo alkali metal doping, which ultimately led to an enhancement in the first hyperpolarizability. By doping alkali metal lithium, three new compounds Li@3, Li@4 and Li@5 were theoretically designed. Then the alkaline earthide Mg was doped onto the Li@3, and a new alkaline earthide compound Li+(3)Mg− was designed. The geometric structure and nonlinear optical properties of the molecules were studied using the CAM-B3LYP functional. The results show that Li+(3)Mg− has a considerable first-order hyperpolarizability, β0 = 21401 au, The β0 value for the 3 system is merely 37 au, whereas for the Li@3 system, it reaches a high of 12257 au Li+(3)Mg− exhibits a β0 value that is over 500 times greater than that of 3. It is evident that the electronic structure and nonlinear optical properties are significantly affected by the presence of alkali metal and alkaline earthide atoms doped in 3. The excess electron derived from alkali metal atoms and alkaline earthide atoms are significant contributors to the sudden increase in the β0 within Li+(3)Mg−. We sincerely hope that the development and production of materials with nonlinear optical properties in this study can provide new ideas and methods for the innovation of electride.

Exploring the bonding and aromaticity of [Au3{C2H2N2E(L)2}3]+ (E = Si, Ge and L = –CH3, -H, -CF3, –NO2): Trinuclear gold superalkali complexes

Coinage metal [Cu, Ag, Au] complexes, with carbene analogous ligands, especially silylene, and germylene, have been getting attention in recent years for their potential applications, either in homogeneous catalysis or in photophysical properties. In this study, we have designed trinuclear gold complexes with different substituted silylene and germylene and observed that these trinuclear gold complexes are stable in cationic form and behave like a superalkali. Conceptual density functional theory (CDFT) based descriptors like electrophilicity give the idea about the reactivity of these superalkali complexes. Negative NICS values determine the aromatic nature of the trinuclear core of these complexes. Atom in molecules (AIM) study has been performed to gain a clear idea about the bonding nature of complexes. Energy decomposition analysis (EDA) suggests that electrostatic interaction stabilizes the complex. First-order hyperpolarizability calculation confirms their high nonlinear optical (NLO) properties.

Structure, Spectroscopy, and Theoretical insights on Co-crystals of 2,4-Diamino-6-Methyl-1,3,5-Triazine Bis(4-Aminobenzoic acid) Monohydrate as a promising anti-cancer agent

Co-crystals of 2,4-diamino-6-methyl-1,3,5-triazine bis (4-aminobenzoic acid) monohydrate (hereafter named DMTAB) have been grown from a slow solvent method at room temperature. Single crystal XRD reveals the centrosymmetric nature of the grown crystal with the P21/n space group. Hirshfeld Surface analysis has been performed to visualize and analyse the spatial distribution of intermolecular interactions in a molecular system. The presence of functional groups has been analysed with Fourier Transform Infrared and Raman studies. By employing NBO analysis, valuable insights into the nature of chemical bonds, electron delocalization, and the overall stability of molecular systems have been examined. Theoretical UV–Vis spectrum studies using Time-Dependent - Density Functional Theory (TD-DFT) in different solvents provide a valuable computational tool to predict and understand the electronic transitions of molecules. HOMO-LUMO analysis and density of states spectrum in different solvents further shed light on the electronic structure and reactivity of molecules in their surroundings. First-order hyperpolarizability calculations have been used to analyse the nonlinear optical response of a grown material. Molecular docking studies were conducted to anticipate the binding conformation of the DMTAB ligand with the relevant target proteins, specifically the ovarian cancer target (Rad6 ubiquitin-conjugated enzyme [PDB ID: 2YB6]) and breast cancer target (protein kinase CK2 [PDB ID: 6HNY].

Tailoring optical and photocatalytic properties of sulfur-doped boron nitride quantum dots via ligand functionalization

Boron nitride quantum dots (BNQDs) have emerged as promising photocatalysts due to their excellent physicochemical properties. This study investigates strategies to enhance the photocatalytic performance of BNQDs through sulfur-doping (S-BNQDs) and edge-functionalization with ligands (urea, thiourea, p-phenyl-enediamine (PPD)). To analyze the geometry, electronic structure, optical absorption, charge transfer, and photocatalytic parameters of pristine and functionalized S-BNQDs, we performed density functional theory calculations. The results showed that S-doping and ligand functionalization tune the bandgap, band energies, and introduce mid-gap states to facilitate light absorption, charge separation, and optimized energetics for photocatalytic redox reactions. Notably, the PPD ligand induced the most substantial bandgap narrowing and absorption edge red-shift by over 1 electron volt (eV) compared to pristine S-BNQD, significantly expanding light harvesting. Additionally, urea and PPD functionalization increased the charge transfer length by up to 2.5 times, effectively reducing recombination. On the other hand, thiourea functionalization yielded the most favorable electron injection energetics. The energy conversion efficiency followed the order: PPD (15.0%) > thiourea (12.0%) > urea (11.0%) > pristine (10.0%). Moreover, urea functionalization maximized the first-order hyperpolarizability, enhancing light absorption. These findings provide valuable insights into tailoring S-BNQDs through strategic doping and functionalization to develop highly efficient, customized photocatalysts for sustainable applications.

Molecular Dynamic, Hirshfeld Surface, Computational Quantum and Spectroscopic analysis of 4-Hydroxy-1-Naphthaldehyde

aims: Computational Quantum and Spectroscopic analysis of 4-Hydroxy-1-Naphthaldehyde Background: Known also as 4-Hydroxynaphthalene-1-carbaldehyde, 4-hydroxy-1-naphthaldehyde (4H1NA) is a crucial precursor of many coordinating agents. A commercial compound called 4-hydroxy-1-naphthaldehyde (4H1NA) can be used to make a number of different sensors. In the development of many chemosensors, they operate effectively as a functionalized fluorescent backbone. Objectives: Molecular Dynamic, Hirshfeld Surface, Computational Quantum analysis of Naphthalde-hyde. Methods: The methods employed in the analysis of the compound involve the DFT calculations, using the DFT method and B3LYP/6-311++G (d, p) basis set with respect to its FTIR, NMR, and UV-Visible spectrum. The NMR chemical shifts of carbon and protons in CDCl3 were determined by the GIAO method. For the molecule of reference, HOMO-LUMO and Donor-Acceptor interactions were also taken into consideration. Investigations also looked into E.L.F., Fukui activity, and non-linear optical properties. Results: The investigation of compounds at their atomic level was analyzed using computational methods so that chemical, medicinal, and environmental research make use of them to make the molecule more in an improved form with distinguished properties. Strong interaction has been produced as a result of electron transfer from the oxygen atoms lone pair LP (2) to the anti-bonding orbital *(C3-C5) with a significant stabilization energy of 42.61kcal/mol. The attributes of the NLO molecule were calculated and found to be superior to those of the urea molecule, with linear and first-order hyperpolarizability situations. Our findings imply that the reference molecule can be a heavier contender for NLO as a surface material and could be considered a vital substance for medical purposes in the drug industry due to its maximum electrophilicity index. Conclusion: A commercial compound called 4-hydroxy-1-naphthaldehyde (4H1NA) can be used to make several different sensors. The compound has good structural and optical properties. They can be employed for a variety of optical limiting applications because of their unusual optical characteristic, which exhibits third-order non-linear behavior.

A Quantum Chemical Investigation on Structural, Spectroscopic and Nonlinear Optical properties of an Organic Molecule Serotonin

Serotonin, a neurotransmitter known for promoting feelings of happiness and optimism, was the subject of theoretical studies conducted using Gaussian software. In these experiments, the 6-311++G/B3LYP basis set was employed. The finite-field-based B3LYP/6-311++G (d,p) approach was used to compute the first-order hyper polarizability and associated properties of this chemical system. Additionally, a Natural Bond Orbital (NBO) analysis was conducted to assess the molecule's stability, taking into account hyper conjugative interactions and charge delocalization. Additionally, HOMO-LUMO energy levels were computed to assess whether a chemical exhibits electrophilic or nucleophilic characteristic. TD-DFT simulations were conducted to examine the electrical and optical characteristics of the material, including absorption wavelengths and excitation energy. Subsequently, the chemical compound's electrophilic or nucleophilic nature was determined by calculating the molecular electrostatic potential (MEP).

Single-and double transition metal atoms anchored C2N as a high-activity catalyst for CO oxidation: A first-principles study

The oxidation of CO has attracted great interest in recent years due to its important role in enhancing the catalyst durability in fuel cells and solving the growing environmental problems caused by CO emissions. Consequently, the catalytic oxidation of CO at double non-noble metal atoms anchored C2N is investigated using density functional theory (DFT) computations. All the screened Ti@C2N and Ti2@C2N are thermodynamically stable based on their binding energy calculations. The electronic characteristics, the natural bond orbital analyses (NBO), Frontier orbital, statistical thermodynamics, projected densities of states (PDOS) characteristics, non-covalent interactions (NCI), and quantum theory of atoms in molecules (QTAIM) descriptors of these systems have been examined to analyze the interaction process. Our comparative study suggested that the newly predicted double-atom catalyst (Ti2@C2N) is highly active for CO oxidation, which is a useful guideline for further development. The calculated static first-order hyperpolarizability (βo) illustrated that the double-atom catalyst under investigation can be considered a potential candidate for non-linear optical behavior and could be used for NLO applications. CO oxidation on Ti2@C2N along the Eley–Rideal (ER) mechanism with a low energy barrier of 0.16 eV, which is smaller than the maximum energy barrier (0.73 eV) of CO oxidation along the Langmuir–Hinshelwood (LH) mechanism. Consequently, the ER mechanism is more favorable both thermodynamically and dynamically. This work can provide useful insights and guidelines for future theoretical and experimental investigations to promote the design and development of highly effective and low-cost non-precious-metal Ti2@C2N nanocatalysts towards CO oxidation at ambient temperature.

Investigation of nonlinear optical properties of a group of transition metal-decorated B12N12 nanocages: A DFT study

BN nanostructures are a promising group of materials with different technical applications. In this study, the electronic characteristics and NLO response of a group of B12N12 nanocages modified by transition metals have been studied using the DFT approach. Population analysis has been performed to investigate the role of transition metal in the delocalization of electronic charge on the surface of nanostructures. In this regard, molecular electrostatic potential (MEP) maps and density of state (DOS) plots have been surveyed. Based on frontier molecular orbitals (FMOs) energies, the reactivity of considered nanostructures has been discussed in the framework of global reactivity descriptors. NLO properties of considered nanostructures in terms of dipole moment, the mean polarizability, the anisotropy of the polarizability, the first-order hyperpolarizability, and the mean second-order hyperpolarizability have been studied in the gas phase and in the presence of Ethanol as solvent. The correlation between the NLO response of the nanocages and their different electronic characteristics has been studied. Results show that the presence of solvent makes an apparent increase in their NLO response. Electronic transitions responsible for absorption spectra of B12N12 nanocages have been considered, too.

Studying the first order hyperpolarizability spectra in chalcone-based derivatives and the relation with one- and two-photon absorption transitions.

The first-order molecular hyperpolarizability (β) dispersion was measured in seven chalcone-based molecules utilizing the tunable femtosecond hyper-Rayleigh scattering (tHRS) technique. Additionally, a theoretical model based on photophysical parameters was employed to better understand β dispersion. Due to the distinct substitution patterns of the aryl/heteroaryl rings within the chalcone structure, varying profiles of one- and two-photon absorption spectra and β dispersion were observed. The applied model highlighted two important factors contributing to achieving high β values: (i) the presence of red-shifted one-photon and two-photon absorption bands; and (ii) the number of discernible absorption bands. To contextualize these results with other molecular structures, we employed the HRS figure of merit (FOM). Remarkably, it was revealed that chemically engineered small chalcone molecules exhibit a FOM comparable to larger quadrupolar and octupolar ones. This underscores the significance of tHRS scattering measurements and their correlation with absorptive parameters in the design and characterization of nonlinear optical materials.

Synthesis, quantum chemical studies, molecular docking, molecular dynamics simulation and ADMET studies on 2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1, 4,5-triphenyl-1H-imidazole derivatives

A novel 2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1,4,5-triphenyl-1H-imidazole (DDTI) molecule was synthesised and characterised by FT-IR and NMR (1H and 13C) spectral techniques. The molecular structure was optimised using the density functional theory (DFT) method with B3LYP/6-311 G (d, p) basis set. Natural bonding orbital (NBO) analysis was used to determine the electron densities of donor (i) and acceptor (j) bonds as well as the hyperconjugative interaction energy (E ( 2) ). In highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculations, the smaller energy gap value was discovered. Molecular electrostatic potential has been analysed. The Mulliken atomic charges of the carbon, nitrogen and oxygen atoms were calculated at the same level of theory. The dipole moment, polarizability and first-order hyperpolarizability demonstrate the good nonlinear optical (NLO) feature of the title molecule. Molecular docking studies are implemented to analyse the binding energy of the DDTI compound against standard drugs such as the crystal structure of ADP ribose phosphatase of NSP3 from SARS-CoV-2 in complex with MES, SARS-CoV-2 main protease with an unliganded active site (2019-nCoV, corona virus disease 2019, COVID-19) and the crystal structure of COVID-19 main protease in complex with an inhibitor N3 found to be considered having better antiviral agent. Molecular dynamics simulation was performed for COVID-19 main protease (Mpro: 6WCF/6Y84/6LU7) to understand the elements governing the inhibitory effect and the stability of interactions under dynamic conditions. Virtual ADMET studies were carried out as well and a relationship between biological, electronic and physicochemical qualifications of the target compound was determined. Toxicity prediction by computational technique for the title compound was also carried out.

Spectroscopic Quantum Calculations Using Density Functional Theory and Molecular Docking Simulations on 2-(4-Methoxystyryl)-4,6-Bis(Trichloromethyl)-1,3,5-Triazine as Potent Inhibitor against SARS-CoV-2

The present investigation is insightful in discerning the experimental and computational spectroscopic behavior of 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5 triazine (MSTCMT) by employing density functional theory (DFT) at B3LYP/6–311++G(d,p)/cc-pVDZ basis sets. The detailed vibrational analysis has been carried out using FT-IR and Raman within 3500–400 cm−1 and 3500–600 cm−1 respectively assisted by VEDA. Chemical shifts obtained from nuclear magnetic resonance (NMR) provided essential information useful in analyzing the molecular structure of MSTCMT. The thermodynamic functions of the MSTCMT molecule have been calculated at 298.15 K using the B3LYP method at 6–311++G(d,p) and cc-pVDZ basis sets. The non-linear optical properties such as polarizability, first-order hyperpolarizability, and second-order hyperpolarizability of the MSTCMT molecule have been calculated using 6–311++G(d,p) and cc-pVDZ basis set at B3LYP level. Molecular docking has been performed to check the inhibitory effect of MSTCMT against the SARS-CoV-2 receptors.

Vibrational (FT-IR), electronic (UV-Vis), thermodynamic, and NBO analyses of amide ↔ imide forms of articaine: a computational perspective on prototropic tautomerism

Herein, the molecular structures of amide ↔ imide tautomers of articaine (ART) were computationally investigated at the DFT/B3LYP/6–311++G (d,p) methodology. Experimental FT-IR and UV-Vis characterisation results of ART were compared with the theoretical results of amide (ART-A) and imide (ART-I) forms. Thermodynamic parameters computed for each phase revealed that the amide tautomer of ART was preferred with energy values in the range of 11.9–13.8 kcal/mol. The modification in surface properties as a function of prototropic tautomerism in the ART molecule was studied by electrostatic surface properties (ESP) analysis. Frontier molecular orbital (FMO), natural bond orbital (NBO), and nonlinear optical (NLO) analyses were performed. It is revealed that energy gap values of the ART-I (4.670–4.738 eV) for each phase are slightly higher than those of the corresponding phases in the ART-A (4.515–4.586 eV). Therefore, it can be concluded that the imide form exhibits lower chemical reactivity compared to the amide form. Regarding NLO characteristics, dipole moment (μtot ), mean polarisability (αtot ), and mean first-order hyperpolarisability (βtot ) values of tautomers have been reported. It was determined that the βtot values computed for ART-A (0.653 × 10−30 esu) and ART-I (0.710 × 10−30 esu) were approximately twice the value of the standard urea.

Computational studies into the chemical nature, thermal behaviour, solvent role, reactivity and biological evaluation of Rigidin E – A marine alkaloid with potent liver cancer inhibition

The current work includes theoretical studies of Rigidin E (marine alkaloid) molecule with the DFT technique and evaluation of its biological properties in silico. DFT calculations in different media were performed for the title molecule. Gradual changes were noticed in the properties of the title compound when subjected to solvation in polar solvents. Electron density distribution, interaction and excitation were demonstrated using topological studies (ELF, LOL, RDG, and charge transfer) done using Multiwfn software. From FMO analysis, methanol is the solvent in which the title compound has the highest band gap value (3.8972 eV) compared to other solvents, and in the gas phase it has a band gap value of 3.6886 eV. Theoretical UV studies show that n -->π* and n -->σ* electronic transitions are significant in Rigidin E. In water, the title molecule has a first-order hyperpolarizability about 100 times that of the reference substance urea, indicating its powerful NLO potential in aqueous medium. ADMET profile was generated using online tools (ADMET lab 2.0, PreADMET, and SwissADME). For the title molecule, docking was done against select liver cancer targets using AutoDock Tools and the lowest binding affinity was obtained −4.62 kcal/mol against 4H6J protein.