6-31G Basis Set Research Articles

Analyzing the impact of the size of fluoro and chloro substituents on induced mesomorphism in hydrogen bonded liquid crystals.

Synthesis of new supramolecules with specific properties and realistic applications requires a sound knowledge of the structure-property relationships of the synthesized molecules. Non-covalent interaction like hydrogen bonding is conducive in realizing mesomorphism. The induction of the liquid crystalline character is associated with the strength of hydrogen bonds formed between the interacting components, which are affected by the change of polarity and polarizability of both components upon change in their terminal polar substituents. When the polar substituents are similar in their reactivity, how does the size of the polar substituent influence the mesomorphism? New hydrogen bonded liquid crystals are synthesized with fluorine and chlorine as substituents, and the mesomorphic behaviour is studied with the size of the substituent as a critical parameter. The chemical characterization is carried out by FTIR measurements, the phase characterization by polarizing optical microscopy and the thermal characterization by differential scanning calorimetry. The DFT method utilizing wb97x-D theory along with the cc-pVTZ basis set were used for the calculations. The hybrid functional B3LYP-D3 and Gaussian type basis set 6-31G(d,p) were used for studying the orientation of the molecules. It is observed that the ortho substituents reduce the co-planarity, meta substituents lead to the molecular broadening while para substituents exhibited highest mesomorphism by enhancing longitudinal dipole moment. Fluoro substituted compounds are exhibiting higher mesomorphism while the bulky chloro substituents are helping to better stack the molecules possessing longer chain lengths.

Synthesis, biochemical characterization and computational investigations of newly synthesized crystal structure of Dihydropyrimidin-2(1H)-thione

The novel 1-(2,6-dibromo-4-fluorophenyl)-4,4,6-trimethyl-3,4-dihydropyrimidine-2(1H)-thiones molecule has been synthesized through a convenient and simple protocol by the facile reaction of acetone, potassium thiocyanate and 2,6-dibromo-4-fluoroaniline. The structure of synthesized compound has been confirmed by spectroscopic (IR, 1H NMR, 13C NMR,), elemental and single crystal analyses. The x-ray studies exhibited the presence of two six-fold ring planes that are almost perpendicular with a dihedral angle of 89.84(7) °. The crystal studies employing Hirshfeld surface (HS) analysis revealed the presence of large number of H … H, H … Br/Br … H, H … S/S … H, H … F/F … H and H … C/C … H interactions suggesting the major role of van der Waals interactions and hydrogen bonding in the crystal packing. DFT studies were performed using the B3LYP function and 6-31G basis set to optimize the molecular geometry. Both in-vitro enzyme inhibition analysis and in-silico molecular docking studies were conducted to confirm the antidiabetic and anti-Alzheimer’s effects. The enzyme inhibition data demonstrated the potent inhibitory activity against acetylcholinesterase (65.5 ± 2.6 µM), butyryl cholinesterase (125.5 ± 2.0 µM) and α-glucosidase (156.0 ± 5.1 µM), while a lesser effect against α-amylase enzyme. These results were further confirmed by in-silico studies which showed strong binding interactions within the active site of target receptor proteins such as α-amylase, α-glucosidase, acetylcholinesterase and butyryl cholinesterase respectively. These findings highlight the potential of compound 4 as a therapeutic agent for the treatment of diabetes and Alzheimer’s disease.

Using single and double laser pulses on the molecular Ni4@C48H36 system to design integrated nanospintronic units.

The accomplishment of long-distance spin transfer scenarios between several magnetic centers is a big challenge for building and supporting spin-logic units for developing future all-optical magnetic unit operations. Using high-level quantum chemistry theory CCSD and EOM-CCSD, we systematically study the ultrafast laser-induced spin-dynamics process on a carbon-based material, to which four magnetic centers are attached. We show that the CCSD method with the 6-31G basis set calculation is sensitive to the C-Ni bond length. The spin density distribution, which is computed using EOM-CCSD with LanL2DZ+ECP calculations, Mulliken population analysis, including spin-orbit-coupling (SOC) and a magnetic field, fulfills the requirements for achieving spin dynamics processes. Different local spin-flip and spin-transfer processes are accomplished within the subpicosecond regime. The impact of the propagation direction of the laser pulse by switching their polar and the azimuthal angles in spherical coordinates on the spin dynamics processes is analyzed. Double laser pulses with time delay δt ≥ 200 × FWHM yield in a realistic magnetic field gradient selectively a lateral resolution, which corresponds to distances smaller than the CMOS scale (2 nm in 2024) while our system size is comparable to the CMOS scale. Here Λ and V processes with two quasi-degenerate intermediate levels are used. We propose a model of an integrated spin-logic processor created from an array of individual spin-logic blocks, which are realized by four magnetic centers Ni. The findings of this study demonstrate the enormous potential of using laser-induced spin dynamics as the fundamental mechanism for future molecular magnetic technology.

Neomangiferin, a Naturally Occurring Mangiferin Congener, Inhibits Sodium-Glucose Co-transporter-2: An In silico Approach.

Type 2 diabetes is a major health concern contributing to most of diabetic cases worldwide. Mangiferin and its congeners are known for their diverse pharmacological properties. This study sought to investigate the inhibitory property of naturally occurring mangiferin congeners on sodium-glucose co-transporter 2 protein (SGLT-2) using comprehensive computational methods. The naturally occurring mangiferin congeners were subjected to molecular docking, molecular dynamics (MDs) simulation (100 ns), molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding free energy, density functional theory calculations (B3LYP 6-31G basis set), and ADMET approaches to identify potential SGLT-2 inhibitor. The molecular docking studies revealed neomangiferin (-9.0 kcal/mol) as the hit molecule compared with dapagliflozin (-8.3 kcal/mol). Root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF) plots from the MD simulations established that neomangiferin stabilizes SGLT-2 better than the dapagliflozin, a standard drug. The MM-PBSA binding free energy calculations showed that neomangiferin (-26.05 kcal/mol) elicited better binding affinity than dapagliflozin (-17.42 kcal/mol). The electronic studies showed that neomangiferin (3.48 eV) elicited high electrophilicity index compared with mangiferin (3.31 eV) and dapagliflozin (2.11 eV). Also, the ADMET properties showed that the hit molecule is safe when administered to diabetic subjects. The current in silico studies suggest that neomangiferin could emerge as a promising lead molecule as a SGLT-2 inhibitor.

Comparative Computational Study on Molecular Structure, Electronic and Vibrational Analysis of Vinyl Bromide based on HF and DFT Approach

In this study, we have used the Hartree-Fock and Density Functional Theory method of calculation and compared the equilibrium configuration, electronic and vibrational mode of Vinyl Bromide molecule. The molecule is geometrically optimized initially by using 6-31G basis set with B3LYP functional and then bond angles, bond lengths, dihedral angles and IR spectra are compared respectively. Various groups of atoms in Vinyl Bromide molecule by DFT has more accurate bond length, bond angle values rather than by HF computation when comparing with the experimental values. The ground state energies are found at angle 10° or 180° or 360° using HF and DFT method of calculation for the H4-C1-C2-Br6 position. Values of the carbon-hydrogen, carbon-carbon and carbon-bromine bond lengths and bond angles for optimization state of C2H3Br molecule using Hartree-Fock and Density Functional Theory methods with respect to the basis set 6-31G have been analyzed. The C−H in-plane bending vibration and C−H out-of-plane bending vibrations occur in the region 1400–1050 cm-1 and 1000–675 cm-1 respectively. The electronic properties, such as Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital energies are performed by HF and DFT approach and the difference in Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital energy gap for HF and DFT method are 14.0847 eV and 6.8994 eV respectively

Mechanistic enhanced cell voltage based on halides doped metal oxide fullerenes for use in Li-ion batteries: Insights from DFT intuition

Designing of anode nanomaterials with an optimum cell voltage is an important challenge for high-performance lithium (Li) ion batteries. In this study, we have investigated the electrochemical potential of pristine and Li-doped magnesium oxide (Mg12O12) and zinc oxide (Zn12O12) fullerenes through density functional theory (DFT) simulations, with a focus on their potential applications in lithium-ion batteries. Specifically, we investigated the halide ion encapsulated oxide nanocages as a means to achieve this improvement. We examined both unaltered and halide encapsulated Mg12O12 and Zn12O12 with Li atom/lithium cation (Li/Li+). Our investigation delves into the geometric and electrochemical characteristics of Li/Li+ interactions with Mg12O12 and Zn12O12 nanocages. We analyzed adsorption energies (Ead) and frontier molecular orbitals (FMOs) of Li/Li+ ions with these nanocages to gain insights into how neutral or ionic Li affects their geometric and electrochemical properties. The initial cell voltages of bare Mg12O12 and Zn12O12 are found to be 0.61 and 0.57 V, primarily due to marginal distinctions in the adsorption energies of Li and Li+ bound systems. Notably, the encapsulation of various halides into Mg12O12 and Zn12O12 nanocages significantly enhanced the cell voltage. Among the considered halides, the encapsulation of fluoride anion (F−) into Mg12O12 and Zn12O12 stands out, leading to a remarkable increase in cell voltage of 4.05 and 3.55 V for lithium-ion batteries, respectively. Moreover, the use of toluene solvent further increased the Ead values of Li cation with pure and halides encapsulated oxides (Mg12O12 and Zn12O12) nanocages. Ultimately, the Gibb's free also decreased along with the decrease in the cell voltage which is encountered in the acceptable range. The most suitable anode nanomaterial is suggested to be Li doped F−@Mg12O12 which has the most acceptable cell voltage of 1.59 V. The work also leads to more research work on the designing of halides encapsulated oxides fullerenes based secondary batteries for use in electrochemical energy storage devices. This work is a full-length guideline for the experimentalist to synthesize such systems to overcome the energy crises.

Combined Experimental and Theoretical Insights: Spectroscopic and Molecular Investigation of Polyphenols from Fagonia indica via DFT, UV-vis, and FT-IR Approaches.

This review deals with computational study of polyphenolic compounds of medicinal importance and interest for drug development. Herein, four polyphenolic compounds comprising catechol (1), caffeic acid (II), gallic acid (III), and pyrogallol (IV) have been isolated from a medicinal specie, Fagonia indica, by applying silica gel column chromatography. These compounds were identified by using gas chromatography-mass spectrometry (GC-MS) analysis and confirmed by geometric computational analysis. According to computational results, caffeic acid has shown the highest biological activation due to higher chemical softness, electronegativity (χ (eV) = -648.644), and electrostatic potential value (-8.424 × 10-2 to +8.424 × 10-2), while smaller values of chemical potential (-0.269), ELUMO (-0.080), and energy gap (ΔE = 0.149). The Mulliken atomic charges were calculated by using DFT/B3LYP with basis set 6-311G for the determination of active sites. The oxygen atom of catechol showed highest nucleophilic characteristic with a more negative charge (08 = -0.695), and pyrogallol indicated a strong electrophilic center at C14 = 0.415 with a higher positive charge. Moreover, UV-visible absorption spectra and a detailed study of vibrational frequencies for all phenolic compounds by employing the DFT approach with 3-21G, 6-31G, and 6-311G basis sets at the ground-state level showed the great agreement with experimental results. ANOVA has been applied to validate the theoretical data. Results suggest that compounds I-IV are suitable in diverse fields.

Molecular engineering of BTO for superior photovoltaic efficiency: A DFT exploration

In this study, Density Functional Theory (DFT) was employed using Gaussian 09 software to optimize the molecular structures of reference and designed molecules. Various functionals (PBE0, B3PW91, TPSSh, CAM-B3LYP, MPW1P91, ωB97XD, and B3LYP) and basis sets (6-31G(d,p), 6-311-G(d,p), and def2-tzvp) were utilized to determine the optimal computational parameters. The computed results showed that the synthesized molecules with electron-donor groups exhibited decreased binding energies, indicating improved charge transfer. Dipole moments were calculated, revealing that the designed molecules had enhanced solubility in chlorobenzene solvent. These modifications also led to improved charge transmission and exciton dissociation, making the molecules potential candidates for organic solar cells. The designed compounds displayed altered voltage of open circuit (VOC) values and higher fill factor (FF) values compared to the reference molecule. The fill factor values indicated enhanced performance in charge collection and extraction efficiency. The power conversion efficiency (PCE) values of the designed molecules exceeded that of the reference molecule, with BTO-A5 (43.61 %) exhibiting the highest PCE value. Overall, the study demonstrated the potential of the designed molecules for high-performance solar devices. Further research could explore their application in solar energy conversion technologies.

Theoretical studies of electronic and optical characteristics in donor-π-Acceptor (D-π-A) dyes: DFT and TD-DFT methods

Abstract This research focused on enhancing D-π-A organic dyes derived from coumarin and its derivatives, collectively referred to as D-CM-A dyes. The study aimed to improve these dyes by introducing various donors and acceptors to the coumarin structure. Six new coumarin dyes were evaluated, primarily for their potential application in dye-sensitized solar cells (DSSCs) to enhance energy efficiency. The analysis involved calculating the geometry, electronic properties, and optoelectronic characteristics of the dye molecules using DFT and TD-DFT methods with the B3LYP functional and the 6-311G basis set in both gas and solvent phases. The primary focus was to understand how modifications to the π-conjugated D-π-A organic dyes influenced their optoelectronic properties, including key factors such as maximum absorption wavelength (λmax), highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), and energy gap (Egap). Additionally, the study explored the photovoltaic properties of these dyes. The findings highlighted D4-CM-A4 as a promising candidate with the narrowest energy gap, while D1-CM-A1 and D2-CM-A2 showed superior light-harvesting efficiencies (LHE) compared to other derivatives. In conclusion, this study suggests that D1-CM-A1 and D2-CM-A2 are favourable choices for enhancing the performance of DSSCs due to their promising optoelectronic properties.

Chemical reaction and strength of tricalcium phosphate nano-coating application on dental implants by atomistic calculations

The success of dental titanium implants depends on the interaction of the implant with the surrounding bone, including the type of coating that promotes osseointegration. The most popular are calcium phosphate coatings, in particular tricalcium phosphate (TCP). Since cases of delamination of coatings from titanium have been observed in practice, it is important to be able to evaluate and predict the adhesion strength of coatings of different compositions to titanium.The work involves ab initio quantum chemical modeling of the interaction of TCP with titanium oxide and calculation of their binding energy. Considering that titanium instantly oxidizes in air, calculations were carried out with titanium dioxide. The Gaussian09 DFT B3LYP package with the 6-31G basis set was used. We synthesized tricalcium phosphate stepwise by assessing the binding energies between its constituents and titanium dioxide, as well as other structural characteristics including bond lengths, bond angles, dihedral angles, and charges. A method for assessing adhesion strength at the macro level using binding energy values calculated at the nano level is proposed. The values obtained are in reasonable agreement with experimental data and other numerical calculations. Using the methods of micromechanics of inhomogeneous media for the polycrystalline/amorphous structures of hydroxyapatite (HA) and β-TCP coatings, their anisotropic elastic characteristics were averaged and the degree of their closeness to the characteristics of the Ti substrate was compared.A comparison of two CFs showed that HA has an advantage over TCP both in terms of greater chemical affinity with the titanium substrate (higher adhesive bond energy) and in terms of proximity to the substrate in terms of mechanical characteristics (lower stress concentration at the bond boundary).

Structural tailoring via end-capped acceptors of thiophene-based C-shaped non-fullerene compounds with A-π-A backbone for the exploration of photovoltaic response

In the current era, non-fullerene based electron acceptors show remarkable contribution to develop organic solar cells (OSCs) with maximum possible efficiency via improving their optoelectronic properties. Thus, in current report, eight novel A-π-A type dithieno[3,2-b:2′,3′-d]thiophene (DTh) core-based C-shaped non-fullerene acceptors (ETMM1–ETMM8) were designed theoretically by taking ETMMR as reference to achieve highly proficient photovoltaic materials. Hence, a comprehensive density functional theory (DFT) analysis was accomplished by employing B3LYP level in conjunction with 6-311G(d,p) basis set to determine the enhancement of optical as well as photochemical response. Whereas time-dependent density functional theory (TD-DFT) approach was used for excited state calculations of all the investigated chromophores (ETMMR and ETMM1–ETMM8). So, the influence of structural tailoring via end-capped acceptors modifications was explored by utilizing various quantum chemical analyses such as: transition density matrix (TDM), HOMO–LUMO band gap, density of states (DOS), UV–Vis, binding energy (Eb), global reactivity parameters (GRPs), molecular electrostatic potential (MEP) and open circuit voltage (Voc). Remarkably, all the derivatives (ETMM1–ETMM8) exhibited comparable results with that of the reference chromophore (ETMMR). The results of UV–Vis analysis in chloroform solvent fall in the following order for all the modified chromophores: ETMM5 > ETMM3 > ETMM8 > ETMM4 > ETMM7 > ETMM2 > ETMM6 > ETMM1, which demonstrated maximum red shift in ETMM5 (785.257 eV). Fascinatingly, lowest excitation energy (1.579 eV) as well as binding energy (0.319 eV) along with minimum HOMO/LUMO band gap (1.898 eV) suggested ETMM5 as an excellent candidate for high performance OSCs. Concludingly, all the results indicated that modification of end-capped acceptors is an effective alternative approach to obtain desirable optoelectronic properties.

Kinetics, thermodynamics, and DFT studies of phenols oxidative coupling reactions with 4-amino-N, N-dimethylaniline

A spectrophotometric method has been established for the reaction kinetics of phenol oxidative coupling with 4-amino-N, N-dimethylaniline in the presence of potassium dichromate as an oxidant to form C14H14N2O, known as phenol blue. Optimum conditions for the reaction were investigated: maximum wavelength (λ max), linear range, molar absorptivity, and stability constant. The kinetic models were applied to the reaction, indicating that it is a first-order reaction. The activation energy (Ea) and Arrhenius constant (A) were calculated from the Arrhenius equation as 14.89 kJ·mol−1 and 3.75 × 105 s-1 respectively. Thermodynamic parameters were ΔH* 12.37 Kj·mol−1, ΔG* 5.47 kJ·mol−1 and ΔS* 22.77 J·mol−1·K−1 at 30oC.. Results indicate that the formation of the product phenol blue is non-spontaneous and endothermic in nature. Density function theory (DFT) has been done for the comparison between experimental and theoretical results using the common 6-311G(d,p) basis set. The results are in good agreement with each other, proving the reliability of the method. Finally, some preliminary test has been performed to check possibility of the product as dye.

Two new cyclohexenone derivatives: Synthesis, DFT estimation, biological activities and molecular docking study

Two new cyclohexenone carboxylate derivatives (6a-b) were synthesized through an additional ring-forming chalcone. FT-IR, 1H, 13C NMR, and Mass spectroscopy techniques confirmed the skeletons. The antibacterial, antioxidant, and colon cancer HT-29 cell activity of synthetic substances were assessed. Compound 6a's IC50 is 23.95 and 60.28 for its antioxidant and anticancer activities, whereas Compound 6b's IC50 is 27.56 and 62.72, respectively. MIC values for compound 6a are 15.75 ± 1.12, 10.25 ± 1.27, and 65.61 ± 1.72 against Staphylococcus aureus, Escherichia coli bacterial strains, and Candida albicans, respectively, whereas for compound 6b is equal to 18.32 ± 1.53, 12.63 ± 1.36, and 78.91 ± 1.94. Based on the extent of (B3LYP) and a 6-31G (d, p) basis set, the HOMO and LUMO of synthesized compounds were computed using the density functional theory (DFT) method. Energy gaps for products 6a and 6b are 2.8272 and 2.3360, respectively. Docked products had binding affinities of −9.5 and −9.1 for compounds 6a and 6b, respectively, with the crystal structure of recombinant human acetylcholinesterase in complex with donepezil (PDB ID: 4ey7). Consequently, according to experimental and computational studies, compound 6a is more active than compound 6b.

Quantum Chemical and Biological Properties of Coumarin Derivative Compound

This work presents the characterization of 8-t-buthyl-4-methyl-2H- chromen 2-one by quantum chemical calculations and spectral techniques. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO) 1H and 13C NMR chemical shift values of title compound in the ground state have been calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The theoretical vibrational frequencies and chemical shift values show good agreement with experimental values. In addition, DFT calculations of molecular electrostatic potentials and frontier molecular orbitals of the title were carried out at the B3LYP/6-31G(d) level of theory. The title compound was screened for antibacterial, antifungal and antioxidant activities.

Investigation of thermoelectric properties of cadmium selenide CdnSen (n= 7, 11, 13) molecular junctions: a DFT study.

The thermoelectric properties of cadmium selenide (CdnSen) molecular junctions (n = 7, 11, 13) were investigated before and after adding hydrogen atoms. The effects of hydrogen passivation on the transmission and thermopower curves were analyzed. CdSe-diamantane (Cd7Se7) and CdSe-tetramantane (Cd11Se11) junctions exhibited the best thermoelectric performance due to their low surface reconstruction energy, which is attributed to the number of dangling and unsaturated bonds. This study guides the design of new molecular junctions with desired thermoelectric properties. The electrical and thermal properties of cadmium selenide (CdnSen) molecular junctions (n = 7, 11, 13) were investigated using a ballistic quantum transport method based on the non-equilibrium Green's function (NEGF) approach. Thermoelectric properties were calculated for the molecular junctions with different structures before and after hydrogen passivation. Density functional theory (DFT) calculations were performed at the B3LYP level with the 3-21G basis set for the Cd atoms and the 6-31G** basis set for the Se atoms. The SIESTA and GOLLUM codes were used to study the effect of changing the shape and size of each structure on its electrical and thermal characteristics.

Spectroscopic and theoretical study of novel copper(II) complexes based on phenothiazine ligands: UV–Visible absorption and photoinduced electron transfer

This study presents three novel copper (II) complexes based on phenothiazine ligands that were synthesized and revealed their structures by spectral and analytical measurements. The synthesized complexes offered potential opportunities to explore their UV–visible absorption properties and photoinduced electron transfer with triethylamine. We performed density functional theory (DFT) calculations for Cu(II) (HL1)2 compounds and studied their frontier molecular orbitals in different environments. The calculations were done by using PBE1PBE functional and 6-31G(d)/Lanl2dz basis sets. We applied the LANL2DZ basis set for Cu. The treatment of all the other atoms was done by a 6-31G(d) basis set. For the calculation of the electronic structure, the basis set 6–31 + G(d)/Lanl2dz and SMD solvation model with MeCN and DMF were employed. We computed the frequencies to confirm the stability of the structures. Theoretical calculations can help explain the experimental findings, provide insights into the electronic transitions responsible for UV–visible absorption, and elucidate the photoinduced electron transfer processes involved.

Exploring the dual capabilities of BNQDs: a comprehensive study on enhancing photoelectric performance and photoluminescence via ligand functionalization.

Boron nitride quantum dots (BNQDs) are emerging as promising multifunctional nanomaterials for renewable energy and optoelectronics owing to their versatile properties. However, rational design principles to tailor their photoelectric and photoluminescent capabilities remain scarce. This study employs density functional theory (DFT) to provide fundamental insights into using urea, thiourea, and PPD ligands to modulate the bandgap, charge transfer dynamics, and recombination processes of BNQDs. Modeling explains that incorporating specific ligands enables visible light absorption, spatial charge separation, continuous photocatalytic cycling, and high quantum yields in BNQDs. The structure-property relationships established pave the way for targeted synthesis of high-performance BNQD photocatalysts and light emitters. This investigation utilized density functional theory (DFT) with the B3LYP functional and 6-31G(d,p) basis set to optimize the geometries of pristine and ligand-functionalized boron nitride quantum dots (BNQDs). The absorption spectra were generated using time-dependent DFT (TDDFT). A Ti38O76 cluster modeled the TiO2 substrate. The cpcm solvation model in Gaussian 09 defined the toluene solvent. Cohesive energies, charge transfer lengths, recombination rates, and conversion efficiencies were calculated to establish structure-property relationships. Multiwfn analyzed the charge densities. The modeling provides insights into tuning BNQD photocatalytic and photoluminescent properties using specific ligands.

Effect of the Electronic Structure of Para-Substituted Benzaldehyde Benzohydrazone on Its Antimicrobial Activity: A DFT Analysis

Bacillus subtilis is a bacterium that has demonstrated its efficacy across various domains, including industry, agriculture, and commerce, owing to its protective, inhibitory, and biological mechanisms against specific microbes. However, at high concentrations, it can lead to food poisoning and severe infections, resulting in symptoms such as diarrhea and vomiting. Bacterial spores produced by Bacillus subtilis can induce conditions like gas gangrene and tetanus. In this context, benzohydrazones are recognized for their antimicrobial activity, particularly against Bacillus subtilis. This study aims to elucidate the relationship between the electronic structure of para-substituted benzaldehyde benzohydrazone derivatives and their antimicrobial activity. This leads to the proposal of a 2D pharmacophore for predicting the antibacterial activity of these derivatives. The quantitative structure-activity relationship (QSAR) approach employed is the KPG method. The electronic structures were optimized using the density functional theory (DFT) method with the B3LYP functional and the 6-31G (d,p) basis set. Charge and local molecular orbitals were considered in the optimization process. The resulting prediction equation (R=98.95%, R²=97.91%, Adjusted R²=96.76%, F(5,9)=84.52) derived from multiple linear regression provides the basis for the proposed 2D pharmacophore. This equation shows that antimicrobial activity of benzohydrazone derivative is on charge and orbital controlled. This pharmacophore holds potential utility in designing new molecular structures with enhanced activity against Bacillus subtilis.

A selective and sensitive probes of chalcone derivative as a fluorescent chemosensor for the detection of Cr3+ ion

A new chalcone based chemosensor like 6-cinnamoylthiochroman-4-one (AZAN), has been designed and synthesized from 6-chlorothiochroman-4-one and cinnamaldehyde via keto ethylenic linkage. Its amino derivatives were synthesized by using urea (AZANU), thiourea (AZANTU) and 2,6-diamino pyridine (AZANPy) respectively and its metal ion sensing properties were investigated. The sensors can selectively recognize and sense the metal cations by showing different fluorescent characteristics at different concentrations. The fluorescence intensity shows remarkable enhancement by Cr3+ over other common metal ions (Cd2+, Hg2+ and Pb2+). The proposed mechanism can be confirmed by UV–Vis and emission titration. The newly synthesized receptor can sense the metal ions even in nano molar level. The binding or association constant and detection limit of chemosensor to Cr3+ are 1.684 × 105 M−1 and 0.2245 × 10−9 M respectively. A computation using the density functional theory was done to gain detailed insights into the electronic structures of the ligand and its derivatives. B3LYP function and 6-31G(d,p) basis set were used to optimize the ground-state geometry of the chemical and its derivatives.

Theoretical and experimental investigations on 5,12-di(methyl)-quinacridin-ylidene)-7,14-di(rhodanineimine) for optoelectronic applications

In searching for novel organic semiconductors, 5,12-di(methyl)-quinacridin-ylidene)-7,14-di(rhodanineimine) (DQAR) is designed and chemically synthesized by using condensation reaction. The molecular structure of DQAR is supported with spectral measurements. Electronic and geometrical properties of DQAR are investigated be means of combined computational and experimental analyses. Density function theory (DFT/B3LYP) utilizing 6-311G(d,p) basis set are used to optimize DQAR molecular structure and its related geometrical parameters. The intermolecular interactions are calculated using reduced density gradient (RDG) planes. The highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of DQAR are experimentally estimated by using the optical absorbance and cyclic voltammetry techniques. DQAR is used as a third component in the active layer of bulk heterojunction (BHJ) solar cells. The BHJ solar cells based on P3HT:DQAR:PC61BM (P3HT = poly(3-hexylthiophene and PC61BM = [6,6]-phenyl-C61-butyric acid methyl ester) active layers are found to be to be better that those based on only P3HT:PC61BM mainly due to the contribution of DQAR to the photocurrent. The obtained results are analyzed in terms of the computational and experimental data. Our initial results indicate that DQAR can be used in BHJ solar cells fabrications.