Polarizability Values Research Articles

Molecular modelling of Pro-Gly glyproline and its complexes

In the present work, Pro-Gly glyproline and its biologically active complexes with heparin and with the antithrombin-heparin protein complex have been studied using molecular modelling methods. This molecule is used as a drug and exhibits antithrombotic, anticoagulant immunomodulatory, antiulcer, and antidiabetic effects. The conformational profiles of the dipeptide were studied within the molecular mechanics framework, the geometry and energy of intra- and interresidual interactions were estimated for the most stable states of the investigated dipeptide. A comparative analysis of the extended and folded structures of this molecule optimized by the DFT/B3LYP/6-31+G(d,p) method was carried out, the frontier molecular orbitals were calculated, the surface of the molecular electrostatic potential was studied, the effective charges on the atoms were determined, and the dipole moment and polarizability values were calculated. Molecular docking revealed that the folded structure of Pro-Gly glyproline showed a higher affinity value for both heparin and the antithrombin-heparin protein complex. A model of the pharmacophore of the Pro-Gly molecule for its interaction with a specific receptor was proposed. The obtained data form the basis for the development of effective analogs of glyprolines in the complex with heparin, which are more specific concerning their putative target — antithrombin.

Theoretical Investigation of Electric Polarizability in Porphyrin-Zinc and Porphyrin-Zinc-Thiazole Complexes Using Small Property-Oriented Basis Sets.

Porphyrin complexes are of great importance due to their possible applications as sensors, solar cells and photocatalysts, as well as their ability to bind additional ligands. A valuable source of knowledge on their nature is their electric properties, which can be evaluated employing density functional theory (DFT) methods, supporting the experimental research. The present work aims at the application of small property-oriented basis sets in calculation of electric properties in transition metals, their oxides and test coordination complexes. Firstly, the existing polarized ZPol basis set for the first-row transition metals is modified in order to improve atomic polarizability results. For this purpose, optimization of the f-type polarization function exponent is carried out with respect to the value of average atomic polarizability of investigated metals. Next, both the original and the modified basis sets are employed in finite field CCSD(T) calculation of transition metal oxides' dipole moments, as well as DFT calculation of polarizabilities in porphyrin-zinc and porphyrin-zinc-thiazole complexes. The obtained results show that the ZPol and ZPol-A basis sets can be successfully employed in the calculation of linear electric properties in large systems. The optimization procedure used in the present work can be employed for other source basis sets and elements, leading to new efficient polarized basis sets.

Transforming industrial byproduct to eco-friendly functional material: Ground-granulated blast furnace slag reinforced paper for renewable energy storage

This study pioneered an eco-friendly approach for reutilizing Ground-granulated blast furnace slag (GGBFS) in paper production. This investigation is the first study focusing on the usage of paper production that presents both a new usage area of GGBFS and also a new sight. So, it can contribute to save the trees. Also, GGBFS gains economical value in paper production. 15–25 % integrated slag led to markedly enhanced brightness, density and smoothness accompanied by only minor mechanical strength decreases versus pure pulp. Significantly, the electrical analysis revealed a higher conductivity at higher frequency region reaching almost S value near to 1 which might be a good choice for electromagnetic shielding, thus; higher conductivity with increasing slag contents from pure paper's 10−11 S/cm up to 10−6 S/cm for 25 % addition which confirms the modified paper's usefulness as conductive slag agent. Although the higher addition of GGBFS has led to rising in relaxation time basically from 1.77e−4 to 2.95e−3 and based on Debye relaxation, the rising time in relaxation which was observed after the addition of GGBFS reveals better polarizability values 0.29–0.35 compared to control sample 0.26 by which both longer relaxation time and higher polarizability contribute to the ability of energy storage of modified papers. The conductive characteristics and improved qualities demonstrate these recyclable slag-modified papers present unique opportunities for emerging flexible, eco-friendly electronics, capacitors, electromagnetic shielding, and renewable energy storage applications. Overall, novel integration and characterization of slag waste for enhanced sustainable paper products pioneers an unexplored territory.

Refractometry of β-modification LiNH4SO4 crystals with an admixture of Mn2+ and Cu2+

Crystals of β-LiNH4SO4 doped with 2 and 5 wt% of Cu2+ and Mn2+ were synthesized. The crystal structure was determined using X-ray diffraction, and the dispersion of refractive indices and birefringence was investigated. The study revealed that adding impurities increased the absolute values of the refractive indices for all crystal physical directions. As the concentration of Mn2+ and Cu2+ impurities increased to 5%, the average refractive index showed an almost linear increase, attributed to the increase in crystal density due to a decrease in the volume of the unit cell. Furthermore, the impurities of Mn2+ and Cu2+ ions significantly altered the absolute values of birefringence. The refractions, electronic polarizabilities, and dispersion parameters were calculated using the Sellmeier formula, showing that adding impurities increased the values of molar refractions and electronic polarizabilities. The study also found that introducing Mn2+ and Cu2+ impurities shifted the optical isotropic point to the long-wavelength part of the spectrum by approximately 26 and 31 nm, respectively.

Synthesis, Structural, Spectroscopic (NMR, FT-IR and UV-vis), NLO, in silico (ADMET and Molecular Docking) and DFT Investigations of a Flavonol Derivative 2-(4-chlorophenyl)-7-fluoro-3-hydroxy-4H-chromen-4-one

The geometric, spectroscopic and electronic features of the newly synthesized 3-Hydroxy-2-(4-chlorophenyl)-7-fluoro-4H-chromen-4-one have been analyzed using a combination of single crystal XRD, FT-IR, NMR shifts, and UV-Vis. spectroscopic methods both experimentally and theoretically. The molecule has crystallized in orthorhombic space group Pca21 and it has stabilized with C-H···O, O-H···O intra-molecular and O-H···O inter-molecular interactions. The geometric parameters (bond lengths and bond angles), vibrational wavenumbers, 1H and 13C NMR chemical shifts, UV-Vis. electronic transitions, the HOMO (highest occupied molecular orbital) and the LUMO (lowest unoccupied molecular orbital) analyses, NLO (non-linear optical properties) and the MEP (molecular electrostatic potential) surface have been computed by using the DFT/B3LYP quantum chemical method with 6-311++G(d,p) level of theory to compare with the experimental findings. Absorption bands of the molecule have computed around 300 and 360 nm, while observed at 244, 312 and 344 nm in the experimental UV-Vis. spectrum. Moreover, the mean polarizability value of the compound has been calculated 6.47 times greater than urea. The objective of the in silico investigation was to ascertain the biological effect profile of the title compound. The ADMETlab 2.0 web service has been employed to analyze the physicochemical, medicinal chemistry, metabolism, distribution, absorption, excretion and toxicity features of the compound. Its protein kinase CK2 inhibitory activity for the target macromolecule 5M4U has been investigated by means of a molecular docking study to investigate the anti-cancer activity of our flavonol derivative compound.

Evaluating non-linear optical behavior in ionic liquids: Combining ab-initio polarizability with additivity rule

In the field of non-linear Optics, the additivity rule, which both experimental and theoretical researchers utilize, provides a simple and reliable method for calculating polarizability. However, this model neglects crucial factors, such as the solvent, the interaction distance, and external optical fields, leading to inaccurate results. In this study, the role of these parameters on the non-linear optical behavior of the ionic liquid BMIM+⋯BF4−, a system extensively studied for its intriguing non-linear optical properties, is investigated. To do that, first-principles calculations based on the density functional theory are developed; the Lennard-Jones potential is used as the reference model. The results of this study reveal the significant influence of the solvent on the second- and third-order non-linear optical responses, which are strongly affected by ion interactions, underscoring the limitations of the additivity rule in terms of molecular polarizability. The EFISHG values for each solvent are inversely proportional to the dielectric constant; for all considered solvents, it observed a clear dependence of polarizability values on the external field, ranging from 1.675 to 1.638× 10−23 esu. It was also found high sensitivity of the static polarizability to changes in the interaction distance and the solvent choice, ranging from 1.57 to 2.05× 10−30 esu, while considering the additivity rule, this parameter changed to 1.59× 10−30 esu. This information can serve as a reference for both theoretical and experimental researchers.

Exploring the impact of heterocyclic bridges for tuning the amplitudes of Nonlinear optical properties under Gas, IEFPCM and COSMO solvent models

Nonlinear optical (NLO) materials are a distinctive class of materials due to their NLO response and wide range of applications. We present a systematic quantum chemical study for designing triphenylamine based derivatives (1Ph to 3PhDTDZ) by modifying central bridge with various size and types of heterocyclic rings. Density functional theory (DFT) method is used to calculate the NLO properties including linear and third-order NLO polarizabilities (α and γ) by using M06-2X functional coupled with the 6-311G** basis set. The calculation results predict that among the designed compounds, 1PhDTDZ has the highest third-order NLO polarizability of 2347.7 x 10−36 esu and lowest transition energy of 1.828 eV. On the other hand, 3PhDTDZ has a greater amplitude (108.5 x 10−24 esu) of static linear polarizability (αiso). We also computed frequency-dependent third-order NLO polarizability values at various laser wavelengths (1500 nm to 1970 nm). This provides valuable information about the complex interaction between light and matter. Dynamic second hyperpolarizability of electro-optic Pockels effect (EOPE effect, (γ (−ω; ω,0,0)) is calculated at 1500 nm laser wavelength with a larger γ-amplitude of 36708.4 x 10−36 esu. The effect of solvent on α and γ has also been the primary focus of this research. An extensive solvation impact has been studied using integral equation formalism Polarizable Continuum Model (IEFPCM) and Conductor-like Screening Model (COSMO). Magnitudes of αiso and 〈γ〉 have shown variation from gas to solvent methods. While among solvents, amplitudes are seen 3.87 % to 11.29 % greater under the effect of COSMO-methanol than PCM-methanol. The Frontier molecular orbital (FMO) studies found a significant decrease in energy band gaps from 5.75 eV to 2.98 eV. Since our systems exhibit remarkable photovoltaic properties, they can be used as dye-sensitized solar cells (DSSCs). Their open circuit voltage (VOC) ranging from 1 eV to 4 eV. Thus, our designed triphenylamine based derivatives with distinct central heterocyclic bridges showcase remarkable efficiency as NLO materials, with additional benefits of exhibiting good photovoltaic properties.

The reverse-DADI method: Computation of frequency-dependent atomic polarizabilities for carbon and hydrogen atoms in hydrocarbon structures

A specific method, combining some ingredients of the well-known DDA and PDI approaches, has been developed in our group since many years to calculate the absorption cross-sections of carbonaceous nanoparticles based on their atomistic details. This method, here named the Dynamic Atomic Dipole Interaction (DADI) model, requires the knowledge of the position and frequency-dependent polarizability of each atom constituting the nanoparticles. While the atomic positions can be quite easily obtained, for example as the results of molecular dynamics simulations, obtaining the frequency-dependent atomic polarizabilities is a trickier task. Here, a fitting procedure, named the reverse-DADI method, has been applied to calculate the frequency-dependent atomic polarizability values for carbon and hydrogen atoms involved in aromatic cycles or in aliphatic chains, on the basis of frequency-dependent molecular polarizabilities of various PAH and alkane molecules, calculated with the TD-DFT theory, in the UV–Visible range. Then, using these frequency-dependent atomic polarizabilities as input parameters in the DADI model has been shown to lead to an accurate representation of the absorption cross-sections of various PAH and alkane molecules with respect to the corresponding values obtained at the TD-DFT level, with however the great advantage of a much shorter time of calculations. Furthermore, these results are indications of a good transferability of the frequency-dependent atomic polarizability values obtained here to any C or H atom of any PAH or alkane molecule. This opens the way for building large databases of optical properties for carbonaceous species of atmospheric or astrophysical interests.

DFT study of difluoro & trifluoro bi-cyclohexane based dimer for application in electronic and optical devices

This investigation outlines a comprehensive analysis of the electronic and optical characteristics of difluoro and trifluoro bi-cyclohexane-based dimers in different conformations, specifically focusing on two distinct molecules: 4-(2,2,-difluorocyclopropyl)-4′-propyl-1,1′-bi(cyclohexane) and 4-propyl-4′-(1,2,2,-trifluorocyclopropyl)-1,1′-bi(cyclohexane). Utilizing Density Functional Theory (DFT) with advanced functionals M06-2X and B3LYP paired with a 6-311G(d,p) basis set, this study probes the interaction energy, orbital behaviors, and non-linear optical (NLO) properties across two primary molecular orientations such that in-plane and stacked.Our findings reveal that both configurations exhibit remarkable non-linear optical properties as evidenced by significant change in values of polarizability and hyperpolarizability, with the latter suggesting enhanced suitability for NLO applications. This study also ventures into frontier molecular orbital analysis, offering predictive insights into the chemical reactivity and charge transfer phenomena intrinsic to these molecular systems.

Calculation of electron scattering lengths on Ar, Kr, Xe, Rn and Og atoms

Abstract Focusing on the noble gases, we calculate the scattering potential using the Dirac–Coulomb Hamiltonian supplemented with a model polarization potential. We determine the scattering lengths using two methods, namely phase shifts for very small scattering energies and the shape of the wave function for zero scattering energy. We compare our theoretical electron scattering length results on Ar, Kr and Xe atoms with existing experimental and theoretical data. In turn, the results obtained for the first time for Rn and Og atoms require independent confirmation. The analysis conducted indicates that the source of the greatest uncertainty in the obtained results is the literature values of dipole polarizability. The study used the GRASP2018 computational package for bound states and the modified COWF code for continuum states.

Calculation of liquidus in eutectic alkali halide mixtures using thermodynamic perturbation theory

A statistical-thermodynamic model that makes it possible to describe with good accuracy phase equilibria between melt and crystal in binary alkali halide mixtures with common cations and anions is proposed. This model is based on the thermodynamic perturbation theory, which takes into account the charge-dipole contribution to the interionic interaction of binary molten salts using a multicomponent mixture of charged hard spheres as a reference system. Specific expressions for chemical potentials, taking into account the charge-induced dipole interaction in the molten phase, are presented within the developed approach. Considering binary eutectic mixtures NaF–NaCl, CsF–CsCl, NaF–CsF, and NaCl–CsCl as an example, the liquidus curves obtained in two series of calculations are shown: with the equation of state and without it. The discrepancies between the calculated and experimental data on the position of eutectic equilibrium for most of the considered mixtures do not exceed about 10 percent on the temperature scale and 5 percent on the composition when using only the tabulated values of ionic radii and polarizabilities without any adjustment.

Remarkable enhancement of the nonlinear optical behavior towards asymmetric substituted D-π-A dithiophene-based compounds.

Nonlinear optics (NLO) is an interesting field that discloses the interaction between intense light and matter, leading to a deeper understanding of NLO phenomena. Organic chromophores are considered as promising materials for NLO due to their exceptional structural versatility, ease of processing, and rapid response to NLO effects. Functional materials based on thiophene have been indispensable in advancing organic optoelectronics. Specifically, dithiophene-based compounds display weaker aromaticity, reduced steric hindrance, and additional sulfur-sulfur interactions. Hence, by utilizing dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene (DTBDT) as the core structure, designing of a set of organic compounds with D1-π-D2-π-A-type framework, namely ZR1D1-ZR1D8, was carried out in this study. The analysis of frontier molecular orbitals (FMOs) revealed that compound ZR1D2 has the lowest band gap of 1.922eV among all the investigated chromophores. The correlation of global reactivity parameters (GRPs) with the band gap values indicates that ZR1D2 displays a hardness of 0.961eV and a softness of 0.520eV-1. Among the studied compounds, ZR1D2 demonstrated a broad absorption spectrum that extended across the visible region. The maximum absorption wavelengths were observed at 766.470nm for ZR1D2 and 749.783nm for ZR1D5. These DTBDT-based dyes exhibit a remarkable NLO response with exceptionally high first hyperpolarizability (βtot) values. Among them, compound ZR1D2 stands out with the highest average linear polarizability (⟨α⟩ = 3.0 × 10-22 esu), first hyperpolarizability (βtot = 4.1 × 10-27 esu), and second hyperpolarizability (γtot = 7.5 × 10-32 esu) values. In summary, this investigation offers valuable insights into the potential use of DTBDT-based organic chromophores, particularly ZR1D2, for advanced applications in NLO. These findings suggest promising opportunities for researchers to synthesize these molecules and utilize these compounds in hi-tech NLO-based applications. The density functional theory computations were performed at the M06/6-311G(d,p) functional to explore their structural effects on electronic and NLO findings. Various analyses like highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps, absorption maxima, density of states, open circuit voltage, binding energies of electrons and holes, and transition density matrix are employed to investigate photovoltaic efficiencies of the derivatives. Different software packages like Avogadro, Multiwfn, Origin, GaussSum, PyMOlyze, and Chemcraft were used to deduce conclusions from the output files.

Change in nonlinear optical response of C24 nanocage upon doping with lithium based superalkalis

Density functional theory (DFT) calculations are used to analyze the change in nonlinear optical (NLO) response, electronic and geometric properties of the Li based superalkalis doped C24 nanocage. It was observed that the adsorption of Li4N, Li3O and Li2F superalkalis on C24 nanocage results in thermodynamically stable isomers (A-F). The energy gap between the highest occupied and the lowest unoccupied molecular orbitals (GH-L) is reduced after superalkalis doping on carbon (C24) nanocage. Density of states spectra depict the strong contribution of superalkalis in HOMOs of the considered complexes. Natural bond orbital (NBO) charge analysis showed that the charge is being transferred from superalkali toward C24 nanocage. The values of polarizability (α o ) and hyperpolarizability (β o ) showed that doping of superalkalis on C24 has a significant effect on its NLO response, resulting in a considerable increase in values of α o and β o . Li4N@C24 isomer E showed the highest β o value of 6470.74 au. Time dependent density functional theory (TD-DFT) calculations are implemented to analyze the absorption spectra. This research provides unique and highly efficient superalkalis doped C24 isomers for their applications in future electronic devices.

Deciphering the impact of superalkali metals [M3O (M = Li, Na, K)] doping on sulflower for enhanced NLO responses with efficient energetic offsets: A density functional theory perspective

With the motive to enhance nonlinear optical (NLO) materials, the geometries, stabilities, and NLO responses of superalkali metals [M3O (M = Li, Na, K)] doped sulflower (Octathio[8]circulene) is explored using DFT simulations and computational characterization. Binding energies from −6.07 to −29.27 kcalmol-1 demonstrate the thermal stability of M3O@sf isomers. The E(H-L) gap was reduced to 84.84 % upon M3O@sf doping. Superalkali metal doping of sulflower substantially improves the first hyperpolarizability (βo) value of complexes. A comparative study illustrates that the hyperpolarizability of the superalkalis has a monotonic relationship with the nature of metal atoms. Among all the studied isomers, K3O@sf-III has the highest βo value of 3.2×107 au. The significant charge transfer (determined by NBO), decrease in excitation energy values, increase in dipole and polarizability values justify that there has been a significant increase in the βo values. This work introduces an opportunity to develop thermally stable NLO materials which can potentially be used for high-performance NLO applications.

Synthesis and optical properties of novel Bi2O3–Li2O–Al2O3–TeO2 glasses

Quaternary glasses of xBi2O3–20Li2O–5Al2O3–(75-x)TeO2 with varying compositions were produced by melt quenching. The purpose was to investigate their physical and optical characteristics. FTIR analysis was employed to examine the structural features of the glass system, followed by UV–Vis spectroscopy for verification of its optical properties. Density measurements performed with a densitometer revealed a rise from 4.68 g/cm³ to 5.06 g/cm³ as the Bi2O3 concentration increased. The refractive index value elevated from 2.6731 to 2.6975 alongside a notable rise in the Urbach energy range from 0.46 to 0.96 eV. As the amount of Bi2O3 varies from 0 to 5 mol%, there was a corresponding rise in the presence of BiO6 units associated with non-bridging oxygen atoms. This observation coincided with a weakening of the bismuth single bond strength, dropping from 283.54 kJ/mol to 158.71 kJ/mol. The optical transmittance decreases to 0.6518, while the reflection loss increases to 0.2108, with an increase in bismuth concentration from 0 to 5 mol%. As the bismuth content increases, both the polarizability of oxide ions and their optical basicity rise consistently, with polarizability values increasing from 2.9163 to 3.0910 Å3 and optical basicity values climbing from 1.0974 to 1.1297. The calculation of interaction parameters indicated that the inclusion of Bi2O3 in glass samples resulted in a shift from high covalency to ionicity, attributed to Bi2O3 acting as a glass modifier.

Synthesis of a new cyclic amide derivative: Study its optical nonlinear properties and molecular docking

2-(1,3-dioxoisoindolin-2-yl)-N-(pyrimidin-2-yl) acetamide is synthesized as a new cyclic amide derivative. The structure of this derivative has been characterized by NMR, FTIR, and Mass spectra. The molecular docking calculations of the prepared cyclic amide against (PDB ID: 3PP0) receptor are performed. The prepared compound has the potential to inhibit breast cancer cells, according to molecular docking results. The DFT/B3LYP via 6–311 G(d,p) level was performed to optimize the geometrical structure and the global and local reactivity descriptors of this compound. The calculated values of polarizability and hyperpolarizability of the prepared cyclic amide equal 30.774 ×10−24 esu and 114.678 ×10−32 esu, respectively. The nonlinear optical (NLO) properties of the prepared compound are studied under irradiation with a visible, cw laser beam. The nonlinear refraction index (NLRI), n2, of the compound is estimated using diffraction patterns (DPs) and the Z-scan techniques, where as high as 2.682 ×10−11 m2/W are obtained. The optical limiting property of the prepared compound is studied using the same laser beam. An optical limiting threshold of 15 mW is obtained.

Effect of partial substitution of K2O by MgO on the structure, and thermal, physical, optical properties and crystallization behaviour of K2O–MgO–B2O3–P2O5 glasses

In this work, a series of K2O–MgO–B2O3–P2O5 (KMBP) glasses were prepared by the melt-quenching method and the glass-ceramics were prepared by the one-step heat treatment. The thermal, structural, physical and optical properties, as well as the crystallization behaviour of the KMBP system, were investigated in detail using characterization techniques such as DSC, XRD, SEM, FTIR, transmittance spectroscopy and microhardness. As indicated by DSC, the thermostability and glass-forming ability were gradually enhanced through the partial substitution of K2O by MgO. XRD showed that the main crystalline phases of the glass-ceramics (GC) were gradually converted from the P–Mg–K–O based crystalline phases to the P–Mg–O based and the P–Al–O based crystalline phases. The SEM results indicated that tiny grain-like crystals were successfully precipitated from the parent glasses after heat treatment. The deconvoluted FTIR spectra results showed a gradual conversion of the [BO3] and [PO3] units towards the [BO4] and [PO4] units with the increase of the MgO contents. The increase in the degree of glass network polymerization was the essential reason for the increment in the microhardness of the parent glasses. The microhardness of GC featured a trend concordant with the crystallinity of the crystalline phases. The values of metallization criteria (MC) between 0.34 and 0.45, as well as the higher values of third-order nonlinear polarizability (χ(3)) and nonlinear refractive index (nnl) are indicative of the good suitability of the KMBP glasses for the nonlinear optical applications.

Realization of the pascal based on argon using a Fabry-Perot refractometer.

Based on a recent experimental determination of the static polarizability and a first-principle calculation of the frequency-dependent dipole polarizability of argon, this work presents, by using a Fabry-Perot refractometer operated at 1550 nm, a realization of the SI unit of pressure, the pascal, for pressures up to 100 kPa, with an uncertainty of [(1.0 mPa)2 + (5.8 × 10-6P)2 + (26 × 10-12P2)2]1/2. The work also presents a value of the molar polarizability of N2 at 1550 nm and 302.9146 K of 4.396572(26) × 10-6 m3/mol, which agrees well with previously determined ones.

Synthesis, spectral, antibacterial and NLO properties of organotin(IV) complexes of Thiosemicarbazones and Semicarbazones

In this study, the antimicrobial and nonlinear optical (NLO) response of thiosemicarbazone, semicarbazone, and their organotin(IV) compounds have been investigated. Organotin(IV) complexes of various types, namely [R2Sn(PhTscz)2], [R2Sn(Tscz)2], [R2Sn(Scz)2], [Bu3Sn(PTscz)], [Bu3Sn(PTscz)], and [Bu3Sn(Scz)] (where R = n-Butyl; methyl; PhTsczH = (±) 2-isopropyl-5-methyl-cyclohexylidene)-N-phenylhydrazine-carboxamide, TsczH = (±) 2-isopropyl-5-methylcyclo-hexylidene)hydrazinecarbothioamide, SczH = (±) 2-isopropyl-5-methylcyclohexyli-dene)hydrazine-carboxamide), were synthesized and characterized by CHN analysis, molar conductivity, UV-Vis, FTIR, and NMR (1H, 13C, 119Sn) spectroscopy, along with theoretical evidence obtained through density functional theory (DFT) simulations. The results showed that the Schiff base (HL) ligands acts as a bidentate NO/NS donor with azomethine nitrogen (N) and deprotonated ketonic oxygen/thionic sulphur (O, S) atoms. [R2Sn(L)2] complexes are assigned a distorted octahedral structure, while Bu3Sn(L) complexes have distorted trigonal bipyramidal structures. The B3LYP/LanL2DZ programme theoretically discussed the electronic structure and nonlinear optical (NLO) properties of the synthesized compounds. The synthesised compounds were evaluated for antibacterial activity using the zone inhibition method. Antibacterial activity of the ligands and its metal complexes against Gram(+) and Gram(-) bacteria demonstrated that the organotin complexes are more potentially resistant to microbial activities than the free ligands. According to the reactivity parameter factors, compound Bu2Sn(Scz)2 (3) is less reactive and more stable. Nonlinear optical (NLO) study revealed that compound (3) had greater linear polarizability (α) values, whereas compound Me2Sn(Scz)2 (9) had higher first hyperpolarizability (βtot) values of 244.29 a.u. Because of their high initial hyperpolarizability values, these molecules have excellent non-linear optical properties and can be exploited as innovative materials in the construction of optoelectronic devices.

Theoretical design of alkaline earthides M+(36 adz) Be− (M+ = V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) with excellent nonlinear optical response and ultraviolet transparency

A novel series of alkaline earthides containing eight complexes based upon 36adz complexant are designed by placing carefully transition metals (V–Zn) on inner side and alkaline earth metal outer side of the complexant i.e., M+(36adz) Be− (M+ = V, Cr, Mn, Fe, Co, Ni, Cu and Zn). All the designed compounds are electronically and thermodynamically stable as evaluated by their interaction energy and vertical ionization potential respectively. Moreover, the true nature of alkaline earthides is verified through NBOs and FMO study, showing negative charge and excess electrons on alkaline earth metal respectively. Furthermore, true alkaline earthides characteristics are evaluated graphically by spectra of partial density state (PDOS). The energy gap (HOMO -LUMO gap) is very small (ranging 2.95 eV–1.89 eV), when it is compared with pure cage 36adz HOMO-LUMO gap i.e., 8.50 eV. All the complexes show a very small value of transition energy ranging from 1.68eV to 0.89eV. Also, these possess higher hyper polarizability values up to 2.8 x 105au (for Co+(36adz) Be−). Furthermore, an increase in hyper polarizability was observed by applying external electric field on complexes. The remarkable increase of 100fold in hyper polarizability of Zn+(36adz) Be− complex is determined after application of external electric field i.e., from 1.7 x 104 au to 1.7 x 106 au when complex is subjected to external electric field of 0.001 au strength. So, when external electric field is applied on complexes it enhances the charge transfer, polarizability and hyper polarizability of complexes and proves to be effective for designing of true alkaline earthides with remarkable NLO response.