Hyperpolarizability Values Research Articles

Alkali metals doped cycloparaphenylene nanohoops: Promising nonlinear optical materials with enhanced performance

In the ongoing pursuit of novel and efficient NLO materials, the potential of alkali metal-doped {6}cycloparaphenylene ({6}CPP) and methylene bridged {6} cycloparaphenylene (MB{6}CPP) nanohoops as excellent NLO candidates has been explored. The geometric, electronic, linear, and nonlinear optical properties of designed systems have been investigated theoretically. All the nanohoops demonstrated thermodynamic stability, with remarkable interaction energies reaching up to −1.39 eV (−0.0511 au). Notably, the introduction of alkali metals led to a significant reduction in the HOMO-LUMO energy gaps, with values as low as 2.92 eV, compared to 6.80 eV and 6.06 eV for undoped {6}CPP and MB{6}CPP, respectively. Moreover, the alkali metal-doped nanohoops exhibited exceptional NLO response, with the K@r6-{6}CPP complex achieving the highest first hyperpolarizability of 56,221.7 × 10−30 esu. Additionally, the frequency-dependent first hyperpolarizability values are also computed at two commonly used wavelengths of 1550 nm and 1907 nm, respectively. These findings highlight the potential of designed nanohoops as promising candidates for advanced NLO materials with high-tech applications.

Nonlinear optical response of Li n ClK (n = 1–6) superalkali clusters

Abstract The geometrical structures, stabilities, electronic properties and nonlinear optical response of the halogen doped bimetallic Li n ClK (n = 1–6) clusters were studied within the density functional theory. Based on the dissociation energy, second order energy difference and GH-L (HOMO-LUMO gap), the Li n ClK (n = 2, 4, 6) clusters are more stable. According to their ionization energies, the clusters can be classified as a superalkali. From the NBO analysis, the clusters are excess electron systems. The obtained first static hyperpolarizability (β o) values are in the range of 1.56 × 104 − 4.33 × 104 au while the second static hyperpolarizability vary within 2.47 × 106 au to 13.9 × 106 au for the Li n ClK (n = 1–6) superalkalis that are slightly higher than the nonlinear optical response of halogen doped monometallic clusters. More importantly, the Li5ClK is transparent in the deep UV region (λ < 300 nm) among the superalkalis indicating that the Li5ClK superalkali can be a candidate structure as new member of NLO materials.

Computational study of Be, Mg and Ca decorated Si12B12 nanocages with proficient nonlinear optical properties

Scientists have paid much attention to nanoscale nonlinear optical (NLO) materials in recent decades due to their promising applications in telecommunications, electronics, and optics. Here, we endeavored to design alkaline earth metals (Be, Mg, and Ca) doped Si12B12 nanocage to meet the rapidly widening requirement for NLO materials. Density functional theory (DFT) and time-dependent DFT (TDDFT) assisted computational tools are utilized to explore the impact of alkaline earth metals doping on the NLO response of Si12B12 nanocage to reveal a unique method for developing NLO materials. Theoretically, ten new isomers of alkaline earth metals doped Si12B12 nanocages are designed. The computational findings demonstrated that the doped isomers of Si12B12 nanocage have significant thermodynamic stabilities, with the highest binding energy of −74.15 kcal mol −1. The E H-L gap is excellently declined upon Be, Mg, and Ca doping and the lowermost E H-L gap is found at 0.92 eV. Calculations using TD-DFT revealed that isomers of the Si12B12 nanocage are transparent in the ultraviolet (UV) region. Confirmation of charge transfer and participation of different segments is explored by natural bond orbital (NBO) and total density of state (TDOS) as well as partial density of state (PDOS) analysis respectively. The types of interactions are investigated using non-covalent interaction (NCI) analysis. The isomer SiB-XV of Ca doped Si12B12 nanocage exhibits the eye-catching static first hyperpolarizability value of 4.71×104 au. Overall findings conclusively confirm that alkaline earth metals doped isomers of Si12B12 nanocage are potential contenders for nanoscale NLO materials because they have excellent stability and boosted NLO response. This research will cover the approach for the fabricating of large NLO response materials for innovative NLO applications.

Synthesis, spectral, quantum chemical, biological, molecular docking and mathematical investigations of piperidin-4-one oxime picrates

By using spectroscopic techniques, the 3,5-diethyl-2r,6c-diarylpiperidin-4-one oxime picrates (DDPPOP and DDMPPOP) were characterised by elemental analysis, FT-IR, 1H, 13C and 2D NMR and mass spectral techniques. The compounds follow a normal chair conformation with all substituents orientated equatorially, as indicated by the reported chemical shifts and coupling constants from the NMR spectral data. The optimised molecular structures of the title compounds were done by using DFT method with B3LYP/6-311++G(d,p) theory. According to the calculated first hyperpolarizability (β0) values of the compounds display non-linear optical (NLO) behaviour. The molecule may have undergone intra-molecular charge transfer, according to the HOMO–LUMO transition. The reactive sites of the title molecule was analysed by using the Molecular Electrostatic Potential (MEP) surface. The Mulliken atomic charges were calculated by using same basis set. The antibacterial and antifungal activity of the title compounds was examined by biological study. Docking studies were thoroughly conducted to establish knowledge regarding the molecular interactions between protein and this compound. This study is further developed and uses the idea of graph colouring in mathematical computation to support the molecular structure we created using NMR spectroscopy.

Effect of charge transfer on the first hyper-polarizability of N,N-dimethylaniline and julolidine: a DFT based comparative study.

Quantum mechanical calculations involving electron correlation, frequency dispersion, and solvent effects were carried out to examine the second-order nonlinear optical response ofvarious acceptor, X (-CF3, -CN, -NO2) substituted in N,N-dimethylaniline (DMA) and julolidine(JLD). Here, both DMA and JLD acts as donor and the three substituted groups, X (-CF3, -CNand -NO2) at the para position of both the ring systems as acceptor. The NLO response (βHRS) of -CF3 and -CN substituted DMA and JLD is relatively lower compared to DMA-NO2 andJLD-NO2. The charge distribution is found higher in case of -NO2substituted DMA and JLD (±443 and ±449) compared to their -CF3 or -CN substitution. Electronic characteristics such asUV-Vis absorption spectra, crucial excited state parameters and charge transfer contribution to βHRS have been used to explain the NLO parameter of DMA-X and JLD-X. Variation of theincident optical frequency of light shows fluctuation of βHRS value and highest values of βHRS are obtain at the λmax frequency of each compound. Solvent polarity variation study on βHRSshows that βHRS varies linearly with the Kirkwood-Onsagar dielectric factor (D). All computational studies have been carried out using density functional theory (DFT) based method. Since CAM-B3LYP based hybrid functional improves the asymptotic behavior of theexchange interaction by dividing into short-range and long-range components, first hyperpolarizability values in the present study were computed using DFT/ CAM-B3LYP/ 6-31G+(d,p) level oftheory.

Utilization of methyclothiazide adsorbed with malonamide for quantum chemical applications: A DFT and DFT-D2/D3 studies

Herein, cost-effective and reliable predictions were made for the optical and electronic properties of the combination of methyclothiazide and melonamide. Interactions between both the title molecules were computationally investigated. The combined structure of both molecules shows the occurrence of immense intramolecular charge transfer from melonamide toward methyclothiazide. Reduction in the band gap of the complex shows the stability of the complex. The combination of methyclothiazide and melonamide gave a red shift in the absorption wavelength to 250 nm. The higher Fourier transform infrared modes corresponding to the -NH bonds of methyclothiazide suggest these groups are suitable adsorption sites for the physisorption of melonamide. The values of first-order hyperpolarizability of the complex were found to be increased to 413.11 au as compared to that of probe methyclothiazide (286.07 au) and melonamide (73.94 au). The observed escalation in the first-order hyperpolarizability shows the potential capability of the proposed combination to be used as strong nonlinear optical materials.

Synthesis, structural and X-ray analysis evaluations and computational studies of newly tetrahydroisoquinoline derivatives as potent against microsomal prostaglandin E synthase 1

Tetrahydroisoquinolines (THIQs) are a significant class within the broad range of natural compounds known as isoquinoline alkaloids. Natural and manmade drugs based on THIQ have a variety of biological effects that protect against different infectious pathogens and neurological diseases. In this study, two new THIQ derivatives were synthesized and characterized using by X-ray crystallographic analysis. The performed Hirshfeld analysis shows the intermolecular interactions and reactive sites of compounds. The 2D fingerprints reveal dominants H···C interactions up to 8.8% in 3a while 43% H···H elemental interactions are observed in compound 3b. In studied compound 3a, the repulsion energies (k-rep) dominate the other energies where the highest amount of 63.8 kJ/mol is obtained whereas 3b has a significant contribution from E-dis to the total energy of the molecule from the energy framework study. Moreover, the density functional theory study reveals better thermodynamic and electronic stabilities. These compounds have reduced HOMO-LUMO gaps (EH-L) ranging from 3.66 to 3.60 eV, indicating their remarkable conductive and electronic properties. The significant reduction in EH-L also guarantees our synthesized compounds’ soft nature and reactivity. Our studied compound’s NBO charges and MEPs analysis show electron-rich sites and donor–acceptor mechanism. Our synthesized compounds have remarkable polarizability (αo) and hyperpolarizability (βo) values (446.23 − 1312.73 au), which indicates their optical and nonlinear optical properties. The density of states spectra further illustrates their notable structural-electronic properties and reduced band gaps. Based on structural activity relationship studies, we found that these tetrahydro-isoquinolines derivatives are potent against microsomal prostaglandin E synthase 1(MPGES1), the docking analysis shows that studied compounds have a good binding affinity with MPGES1, and further ADME/T analysis was carried out for both compounds. In addtion to this molecular dynamics, studies were performed to understand the binding stability of both compounds in protien complex system during 100 ns simulation. Communicated by Ramaswamy H. Sarma

Nonlinear optical response of facially polarized all cis-1,3,5-trifluorocyclohexane doped with transition metals and calcium

Herein, the Janus type complexes have been designed that have the fame as potential candidates in nonlinear optical (NLO11NLO (Nonlinear optics).) materials due to excess electrons. In present work, novel class of excess electronic compounds termed as transition metalides AE-1-TM22AE (Alkaline Earth), 1 (complexant = C6H9F3), TM (Transition Metal). complexes (AE = Ca, Fe/Co/Ni/Cu/Zn)33Ca (Calcium), Fe (Iron), Co (Cobalt), Ni (Nickel), Cu (Copper), Zn (Zinc). have been designed theoretically using highly polarized all axially cis-1,3,5-trifuorocyclohexane 1 (C6H9F3) as complexant bearing a larger dipole moment of 5.42 D. The electronic, thermodynamic and geometric features of Ca-1-TM were studied using M06-2x|6-31++G(d,p) level of theory. More distinctively, transition metalide nature of the complexes has been verified by NBO44NBO (Natural Bond Orbitals). (Natural Bond Orbital) and HOMOs55HOMOs (Highest occupied molecular orbitals). (Highest Occupied Molecular Orbital) density distribution analysis. The thermodynamic stability of transition metalides is evident from large values of interaction energies (-6.99 to −25.01 kcal/mol). The designed complexes showed low excitation energies (2.09–4.01 eV) and high first hyperpolarizabilities (βo) up to 2.16 × 105 (au). Moreover, hyper rayleigh scattering (βHRS) was computed for evaluation of NLO response of complexes. Dipolar and octupolar nature of Ca-1-TM complexes have also been confirmed by the depolarization ratio (DR66DR (Depolarization Ratio).). The higher values of hyperpolarizabilities provided evidences for the existence of excess electrons around transition metals. Two-level model approach was used for rationalization of hyperpolarizabilities. The results illustrated that the generation of these complexes is a novel entry in the metalide that can be recognized as preferable way for designing NLO materials.

Nonlinear optical response of silver trimer adsorbed para-aminobenzoic acid: A DFT study

The reported study is motivated by our previously done experimental demonstration of the optical limiting behavior of para-aminobenzoic acid and enhanced nonlinear optical responses of compounds with Ag3 nanoparticle complex. The present study is a theoretical insight into the nonlinear optical responses of para-aminobenzoic acid adsorbed with Ag3 trimer. The enhancement in the optical nonlinearity of the para-aminobenzoic acid after the adsorption of the silver trimer (Ag3) was accounted in the present study. The density functional theory was used to establish the occurrence of the intra and intermolecular charge transfer between the donor and acceptor moieties of the para-aminobenzoic acid and Ag3 trimer. The molecular electrostatic potential surface and inter-fragment charge transfer analysis were used to establish the donor nature of the Ag3 trimer, amino group, and acceptor of the carboxyl group. The absorption spectra and Fourier-transform infrared spectra were used to account for the electronic and vibrational modes. The value of first-order hyperpolarizability of para-aminobenzoic acid and Ag3 complex was observed to increase by six times that of para-aminobenzoic acid. The high value of first-order hyperpolarizability shows the potential nonlinear optical activity of para-aminobenzoic acid adsorbed with Ag3 trimer. The presented study forms a strong base for experimental demonstration of the nonlinear optical activity of the PABA and the silver nanoparticles and the experimental work will be done in the near future for the NLO responses and optical limiting activity of PABA combined with silver nanoparticles.

A comparative study of electronic structure, adsorption properties, and optical responses of furan and tetrahydrofuran adsorbed pristine, Al and Ga doped B12X12 (X=N and P) nanocages

Removing pollutants like furan (F) and tetrahydrofuran (THF) from the environment is challenging, and adsorption can efficiently remove pollutants. Fullerene like inorganic nanocages B12N12 and B12P12 are known for their efficient adsorption capability. To address these concerns, we report here the adsorption of the F and THF on the pristine and Al and Ga-doped B12N12 and B12P12 nanocages and consequently the change in the electronic structure, property and optical responses. Doping Al and Ga at the nanocage diminishes the HOMO-LUMO energy gap by 2.9 to 0.4 eV compared to the pristine cage, making the doped cage surface more reactive. The doped surface of nanocage adsorbs F (F@AlB11N12 (-130.1 kJ/mole) and THF (THF@AlB11N12 (-202.3 kJ/mole) more effectively compared to pristine ones (F@B12N12 -28.7 kJ/mole, THF@B12N12 (-98.3 kJ/mole) at ωB97XD/6–31+G(d,p) level. For a given cage, THF is more strongly adsorbed (THF@B12N12 (-98.3 kJ/mole)) on the cage surface than F (F@B12N12 -28.7 kJ/mole). Interestingly, Al-doped cages exhibit the highest adsorption energy value ranging from -68.5 kJ/mole to -202.3 kJ/mole. Natural bonding orbital analysis, global reactivity descriptor, molecular electrostatic potential, frontier molecular orbital, etc. have been employed to comprehend the distinctive patterns of adsorption. The optical response properties of the studied complexes show that the complexes of B12P12 nanocages exhibit higher polarizability and second hyperpolarizability value (1.51 × 105 to 1.62 × 105 au) compared to its analogous B12N12 complex (3.62 × 104 to 4.15 × 104 au) at ωB97XD/6–311+G(d,p) level. Our theoretical results further demonstrate the capability of AlB11N12 and AlB11P12 as promising adsorbents of the toxic organic pollutants F and THF, and the computed higher second hyperpolarizability value of the B12P12 complexes indicates these nanomaterials could be used as potential optoelectronic materials.

Investigation Of Spectroscopic And Electronic Properties Of Some Schiff Basesderived From 2-Hydroxy-3-Methoxy-5-Nitrobenzaldehyde By Dft Method

In this study, the theoretical spectroscopic and some electronic properties of MMP and FMP compounds were investigated and the obtained theoretical results were compared with some experimental values. For this purpose, firstly, MMP and FMP compounds were optimized by DFT method using the B3LYP functional and the 6-311G++(d,p) basis set. With the help of the optimized structure obtained, the chemical shift values of H-NMR and 13C-NMR were calculated in the gas phase by the Gaussian G09 (Linux) and Gauss View 5.0 programs according to the GIAO method. According to the results obtained, it was seen that the theoretical values were compatible with the experimental values. In the theoretical part of the study, the IR frequency values of the studied compounds were calculated using the same method and basis set, and vibration frequencies were marked. Finally, the nonlinear optical properties of the compounds of interest; Polarizability and hyperpolarizability values were calculated by making polar calculations in the single point energy calculation. As a result of the calculations, the energy band gaps between the HOMO and LUMO orbitals of MMP and FMP are 1.34 eV and 3.64 eV. First static hyperpolarizability of MMP and FMP were found as 29273.7 x10-33 and 26500.5 x10-33 esu, repectively.

Synthesis, solvent role (water and DMSO), antimicrobial activity, reactivity analysis, inter and intramolecular charge transfer, topology, and molecular docking studies on adenine derivative

In the current study, a molecule (E)-3-(((9H-purin-6-yl)imino)methyl)phenol (A3H) was made and its structure was characterized through the application of spectroscopic techniques. The optimization of the structure of the title chemical was performed using the B3LYP/cc-pVDZ basis set, employing the most stable conformational structure according to the DFT approach. The geometrical characteristics, vibrational wavenumbers, and electrical properties have also been investigated. The electronic characteristics of HOMO-LUMO, UV–Vis, and MEP maps were analysed, including different solvation effects. When compared to the other solvents the water has the lowest energy gap value, due to solvent interaction. The NLO activity has been investigated using the DFT/B3LYP approach, employing the cc-pVDZ basis set. In the NLO study water has the highest dipole moment, polarizability, and hyper-polarizability values. In this study, we have successfully obtained a set of lone pairs of donor–acceptor contacts and a hydrogen bond donor/acceptor surface. These findings provide a basis for explaining a charge transfer process. The utilization of molecular docking techniques has been employed to get insight into the binding interaction between the ligand and targeted proteins.

Two-photon absorption and optical limiting in 7-diethylamino-4-methyl coumarin

The combined experimental and computational spectroscopic calculations were performed to analyze the nonlinear optical property of 7-diethylamino-4-methylcoumarin. The band gap was measured in ten different solvents and found very favorable in dimethyl formamide. The molecular electrostatic potential surface and Hirshfeld’s surfaces were used to determine the reactive sites of the title molecule. Intramolecular interactions were accounted by Mulliken and natural charge distribution, Fukui functions, and fingerprint plots. The electronic transitions were studied by experimental and computed absorption and photoluminescence spectra. Infrared spectroscopy combined with DFT calculation was used to confirm the molecular vibrations related to the chemically active functional groups. The high value of hyperpolarizability showed the enhanced nonlinear optical behavior of the molecule. The Z-Scan plots gave a valley-like shape showing the occurrence of the reverse saturable absorption and the theoretical fit revealed the occurrence of two-photon absorption and the potential application of the molecule to be used for optical limiting applications.

Frequency-dependent nonlinear optical response and refractive index investigation of lactone-derived thermochromic compounds

Nonlinear optical (NLO) switchable materials play a crucial role in the fields of electronics and optoelectronics. The selection of an appropriate switching approach is vital in designing such materials to enhance their NLO response. Among various approaches, thermos-switching materials have shown a 4-fold increase in NLO response compared to other photo-switching materials. In this study, we computationally investigated the geometric, electronic, and nonlinear optical properties of reversible lactone-based thermochromic compounds using the ωB97XD/6-311+G (d,p) level of theory. Molecular orbital studies are employed to analyze the electronic properties of the close and open isomers of these compounds, while time-dependent density functional theory (TD-DFT) analysis is utilized to evaluate their molecular absorption. Our findings reveal that the π-electronic conjugation-induced delocalization significantly influences the ON-OFF switchable nonlinear optical response of the lactone-based thermochromic compounds. Notably, among all compounds, the open isomer of lactone 2 exhibits the highest hyperpolarizability value (6596.69 au). Furthermore, we extended our analysis to investigate the frequency-dependent second and third-order hyperpolarizabilities. The most pronounced frequency-dependent NLO response is observed at 532 nm. Additionally, we calculated the refractive index of these thermochromic compounds to further assess their nonlinear optical response. The open isomer of lactone 1 demonstrates the highest refractive index value (3.99 × 10−14 cm2/W). Overall, our study highlights the excellent potential of reversible thermochromic compounds as NLO molecular thermos-switches for future applications.

The experimental and theoretical spectroscopic elucidation of molecular structure, electronic properties, thermal analysis, biological evaluation, and molecular docking studies of isococculidine

Experimental techniques, such as vibrational spectroscopy (FT-IR and FT-Raman), UV–visible, thermal analysis (DSC), along with quantum chemical calculations based on density functional theory (DFT) were conducted to explore the physicochemical properties of a plant-derived natural product, isococculidine. The potential energy distribution (PED) has been assigned to each of the vibrational bands observed in FT-IR and FT-Raman spectra. The reduced density gradient (RDG) analysis was used to demonstrate the non-covalent interactions (NCI). Natural bond orbital (NBO) study revealed that the benzene ring's hyper-conjugative interactions were primarily responsible for the molecular stability. The intramolecular charge transfer has been further verified by the HOMO-LUMO analysis. The molecular electrostatic potential (MEP) analysis signifies that the nucleophilic and electrophilic interaction sites are prone to oxygen of O1-CH3 and hydrogens of O2-CH3, respectively. The chemical activity and the toxicity of the molecule have been examined based on the calculated Mulliken charges, softness, hardness, and local reactivity parameters. The thermal properties like specific heat capacity, entropy and enthalpy which affect the drug's activities were studied. The large value of the first hyperpolarizability indicates its significant nonlinear optical (NLO) property. The molecular docking of isococculidine has been performed with nicotinic acetylcholine protein which deliberates the significant biological activity of the molecule.

Outstanding NLO response of K3O@thia[n]circulenes; a DFT and molecular dynamics perspective

The nonlinear optical (NLO) response of superalkali (K3O) doped thia[7&8]circulenes (1–18) is analyzed through density functional theory (DFT) calculations. The high interaction energies illustrate thermodynamic feasibility of these complexes. Natural bond orbital (NBO) charge analysis confirmed that electronic charge is transferred from K3O toward thia[7&8]circulenes. Additionally, the lowest unoccupied molecular orbital (LUMO)—the highest occupied molecular orbital (HOMO) energy gaps are reduced up to 0.81 eV after doping. Polarizability (α o) and the first hyperpolarizability (β o) values are used to estimate NLO response of doped circulenes. The highest α o and β o obtained for K3O doped thia[7&8]circulene (9) are 7297 au and 3.03 × 108 au, respectively. Two level model illustrates that the excited dipole moment as decisive factor for enhancement of NLO response. The electronic excitation is confirmed from ultraviolet-visible (UV–vis) spectroscopic analysis where all doped circulenes showed bathochromic shift. Ab initio molecular dynamics depicts strong interaction and high thermal stability of K3O doped thia[7]circulene 9. Thus, K3O doping on thia[n]circulenes (n = 7&8) remarkably enhanced the NLO response which assures the use of respective complexes in designing of building blocks for future optics.

Synthesis, crystal structure investigation, Hirshfeld and DFT studies of newly synthesized dihydroisoquinoline derivatives

Isoquinoline and its derivatives, which constitute an important category of heterocyclic compounds and are found in a variety of naturally occurring alkaloids, serve a variety of biological purposes such as a potent agonist for human melatonin receptors 1. This research was conducted in an attempt to develop new dihydroisoquinoline molecules (III and IV). Single-crystal X-ray crystallography study validated their structures. The Hirshfeld surface analysis identifies intermolecular interactions by using a 2-D fingerprint map to recognize each type's relative contribution H⋅⋅⋅Hconnections are discovered to be dominating. The interaction energies between chemical pairs in crystal structures were found using an energy framework analysis. The DFT investigation demonstrates the electronic stability and reactivity of the compounds using the HOMO-LUMO and global reactivity descriptors, indicating that IV has higher chemical reactivity than III. The derived polarizability (αo) and hyperpolarizability (βo) values were used to calculate the optical and nonlinear optical characteristics of III and IV. The IV's significant βo value (488.94 au) indicates that it has good optical and NLO qualities. Molecular docking simulation using human melatonin receptors 1 was used to better understand the binding interaction mechanism of the title compounds. In addition, ADMET evaluations were performed to establish the therapeutic potential of III and IV.

Structure, Frontier Molecular Orbitals, MEP, Charge Analysis, and NLO Study of 2,4-, 2,5-, and 2,6-Dimethylanilines Using DFT

This study includes the evaluation of most stable structure, frontier molecular orbitals, molecular electrostatic potential (MEP), and nonlinear optical (NLO) parameters of 2,4-dimethylaniline (2,4DMA), 2,5-dimethylaniline (2,5DMA), and 2,6-dimethylaniline (2,6DMA) using density functional theory (DFT) employing B3LYP functional with 6-311++G(d,p) basis set. HOMO-LUMO energies, band gap energies, and global reactivity descriptors were obtained from the optimized structures. The band gap energy was determined as 3.7865, 3.9348, and 3.9443 eV for 2,4DMA, 25DMA, and 2,6DMA, respectively. The reactive sites of the molecules were obtained from the molecular electrostatic potential energy. The NLO parameters such as dipole moment, polarizability, and hyperpolarizability have been investigated for the title molecules. The investigated dipole moment and first-order hyperpolarizability values are higher than the prototypical value of urea and show good NLO behavior. The NMR chemical shifts, electronic absorption spectra, and charge distribution of atoms were calculated theoretically. Furthermore, thermodynamic and rotational constants were also calculated.

Conjugation-modulated optoelectronic and anti-corrosion properties of pyrrole oligomer: Insights from DFT/TD-DFT analysis

To investigate the influence of π-conjugation on optical properties, models of Pyrrole oligomers with varying π-bridge lengths, ranging from 1 to 5, were constructed. The π-bridge plays a crucial role in tuning and modulating the optoelectronic characteristics of these molecules. By employing FMO (Frontier Molecular Orbital) analysis, the band gap values were determined. Notably, the pyrrole oligomer with a 1π-bridge exhibited a higher band gap (2.68 eV) compared to the 5π-bridge variant (1.53 eV). Moreover, the calculated hyperpolarizability (β°) values exhibited a substantial increase from 37 esu to 1876 esu as the extent of π-conjugation was augmented. This suggests that enhanced π-conjugation promotes greater nonlinear optical properties. Further analysis revealed that the pyrrole oligomer with 5π-bridges displayed maximal absorption at a longer wavelength, specifically 1024 nm. This information provides valuable insights into the absorption characteristics of these molecules. Additionally, the NBO (Natural Bond Orbital) analysis successfully captured the stable donor-acceptor interactions responsible for the ground state stabilization observed in pyrrole oligomers. On the other hand, the QTAIM (Quantum Theory of Atoms in Molecules) analysis provided detailed information regarding weak interactions, such as hydrogen bonding, which contribute to the stabilization of the modeled monomers. In summary, the creation of Pyrrole oligomer models with varying π-bridge lengths facilitated the evaluation of the impact of π-conjugation on the optical properties. The findings indicate that increasing the π-conjugation leads to a decrease in the band gap, an increase in hyperpolarizability, and absorption at longer wavelengths. Additionally, the stability of the ground state and the nature of weak interactions were elucidated through NBO and QTAIM analyses, respectively.

Reactivity and Structural Investigation of Tetrahydroneoprzewaquinone A as an Anti-Inflammatory Agent: An Experimental and Molecular Modeling Perspective

This intriguing study aimed to explore the reactivity and structural investigation of (3R,3′R)-2,2′,3,3′-tetrahydroneoprzewaquinone A (THNPQ A) as a potential anti-inflammatory agent. Substantially, the electronic properties were investigated using LanL2DZ, 6-311++G (d,p), and STO-3G basis sets, with electronegativity values of 7.9816, 6.3038, and 5.0166 eV, respectively. The natural bond orbital (NBO) analysis calculations of optimization energies revealed that LanL2DZ had the highest stabilization energy (526.65 kcal/mol) for the interaction between πC8-C9 and πC3-C4. Regarding nonlinear optical (NLO) properties, 6-311++G (d,p) exhibited the highest averaged polarizability and first-order hyperpolarizability values, while the polarizability anisotropies Δtotal followed the order 6-311++G (d,p) (65.2054 a.u.) > LanL2DZ (42.8782 a.u.) > STO-3G (29.9349 a.u.). Analysis of the density of states (DOS) and orbital contribution showed that 6-311++G (d,p) had the highest density peaks at both the highest occupied molecular orbital (HOMO) (–0.5 a.u.) and the lowest unoccupied molecular orbital (LUMO) (0.00 a.u.). The condensed dual descriptors indicated minimal variations in the f A – and f A + values, with an increase in Δf A, f A –, and f A + values following the order STO-3G > LanL2DZ > 6-311++G (d,p). The sites for potential nucleophilic attack were identified as O11, O12, O36, and O37, which exhibited the highest values with the STO-3G basis set. Empirical evidence from in vitro inhibition assays unequivocally validates the potent anti-inflammatory activity of THNPQ A. Particularly noteworthy is its exceptional binding affinity, surpassing that of diclofenac. By establishing conventional hydrogen bonds with the glycine of COX-I and histidine of COX-II, THNPQ A exhibits remarkable potential as an effective agent for combating inflammation. These findings boldly emphasize the promising therapeutic prospects of THNPQ A in the field of anti-inflammatory treatment, positioning it as a compelling candidate for further investigation and development.