Electrostatic Analysis Research Articles

Synthesis of 1-Piperoylpiperidine Investigated Through Spectroscopy, Quantum Computation, Pharmaceutical Activity, Docking and MD Simulation Against Breast Cancer

1-Piperoylpiperidine (1-PIP) was crystallized as a single unit by a slow evaporation process, and it was examined using XRD and FT-IR spectroscopy. The centrosymmetric monoclinic structure is confirmed by XRD. The functional groups were determined by experimental FT-IR range from 4000 to 400 cm−1. Density functional theory was used to do calculations on quantum chemistry on B3LYP/6-311++G (d,p) theory. The vibrational wavenumbers were calculated, and experimentally obtained were assigned and compared. The molecule’s reactivity and kinetic stability are revealed via molecular orbital research. The Mulliken atomic charge distribution and molecular electrostatic potential analyses provide additional evidence of the molecule’s reactive site. The electronic spectrum was computed through TD-DFT and the electronic transition was attained at π→π*. The molecule’s bioactivity is shown by the natural bond orbital analysis. The efficiency and contribution of interactions between various atoms were evaluated using the Hirshfeld analysis. The DPPH assay was performed to access the antioxidant ability of 1-PIP. The disk diffusion test exhibited the antibacterial efficiency of 1-PIP molecule. The safety profile of 1-PIP was confirmed through physiochemical and pharmacokinetic predictions. In silico docking evaluation was performed for 1-PIP against 10 breast cancer-aided proteins and the higher binding affinity was recorded for NAMPT, which was further investigated through molecular dynamic (MD) simulation. MD simulation for a time period of 50 ns confirmed the stability of 1-PIP bounded NAMPT structure.

Novel Fluorinated Biphenyl Compounds Synthesized via Pd(0)-Catalyzed Reactions: Experimental and Computational Studies.

Five new difluorinated biphenyl compounds, 4'-(tert-butyl)-3,4-difluoro-1,1'-biphenyl (TBDFBP), 1-(3',4'-difluoro-[1,1'-biphenyl]-4-yl)ethanone (DFBPE), 3',4'-difluoro-2,5-dimethoxy-1,1'-biphenyl (DFDMBP), 3,4-difluoro-3'-nitro-1,1'-biphenyl (DFNBP), and (3',4'-difluoro-[1,1'-biphenyl]-3-yl)(methyl)sulfane (DFBPMS), have been successfully synthesized by the well-known Suzuki-Miyaura coupling with excellent yields averaging 78%. UV-visible, Fourier transform infrared ,and 13C NMR and 1H NMR spectroscopies along with single-crystal X-ray diffraction (SC-XRD) analysis (for TBDFBP and DFBPE) were used for the structure elucidation of the synthesized compounds. The SC-XRD results demonstrated the crystal systems of the studied compounds, TBDFBP and DFBPE, to be monoclinic, and their space groups were found to be P21/c. Also, a detailed density functional theory study was performed. The calculated structures for TBDFBP and DFBPE were found to agree quite well with the experimental results. The natural bonding orbital charge analysis suggested that molecules of these compounds should interact quite noticeably with each other in the solid phase and with polar solvent molecules. Molecular electrostatic potential analysis suggests that accumulation of positive and negative potential implies possibility of quite significant dipole-dipole intermolecular interactions in crystals of these compounds, as well as quite strong interactions with polar solvent molecules. The global reactivity parameters analysis suggests all compounds to be quite stable in redox reactions, with the compound DFNBP being relatively more reactive and the compounds TBDFBP and DFDMBP being relatively more stable.

Effect of functional group position in co-formers and solvent on cocrystal polymorphism/stoichiomorphism: a case study

In recent years, there has been an increase in the number of reports on cocrystal polymorphism and stoichiomorphism. However, the research on the factors that influence these phenomena is limited. Herein, picolinamide (PAM), nicotinamide (NAM), and isonicotinamide (INA) were selected as co-formers to form multicomponent solids with 4-chloro-3-sulfamoylbenzoic acid (CSBA). Six new cocrystal forms of CSBA were discovered and their crystal structures were determined. It was found that PAM and NAM can only form one cocrystal with CSBA, while INA can form up to four cocrystals, including both cocrystal polymorphism and stoichiomorphism. Molecular electrostatic potential analysis and crystal structure analysis showed that the functional group position of PAM limited the diversity of cocrystal synthons, while the lattice energy limited the diversity of cocrystal synthons when NAM acted as a co-former. Only INA was not subject to these restrictions when forming cocrystals. Finally, the influence of solvents on cocrystals was illustrated by determining the ternary phase diagrams. The mechanism of two similar solvents, ethyl acetate and acetone, controlling the crystallization of cocrystal polymorphism was analyzed by molecular simulations.

Theoretical insight of hydrochlorothiazide and aspirin adsorption on potassium and phosphorus doped carbon nanostructure as polypill prototype

Simultaneous adsorption of drugs on a novel carrier is a challenge for cardiovascular polypill design. The Density Functional Theory (DFT) calculations have been carried out to provide a possible mechanism associated with hydrochlorothiazide and aspirin adsorption on potassium- and phosphor- doped eighteen carbon nanostructure. The energetically most stable geometries are determined. The electronic structure of both molecules, as well as the doping nanostructure, before and after adsorption of the drugs, is studied. The molecular electrostatic potential analysis is presented and the orbital hybridizing is searched by the density of states plots. The results provide a direction for the further experiments in terms of through the recognition of binding trends and how the binding interaction change by modifying the surface.

Dissecting the Effect of Temperature on Hyperthermophilic Pf2001 Esterase Dimerization by Molecular Dynamics.

Pf2001 esterase (Pf2001) from Pyrococcus furiosus has hyperthermophilic properties and exerts a biocatalytic function in a dimeric state. Crystal structures revealed that the structural rearrangement of the cap domain is responsible for the Pf2001 dimer formation. However, the details of the cap domain remodeling and the effects of temperature on the dimerization process remain elusive at the molecular level, taking into account that experimental methods are difficult to capture the dynamic process of dimerization to some extent. Herein, four dimer models based on the monomeric crystal structure (PDB ID: 5G59) were constructed to investigate the conformational transition details and temperature effects in the dimerization by conventional molecular dynamics and accelerated molecular dynamics simulations. Our simulation results indicate that the monomer undergoes a conformational change into a "preparatory state" at high temperatures, which is more favorable for its transformation into a stable dimer. The subsequent free energy landscape analysis further identifies four intermediate states (from separated state to dimeric state) and discloses that a more accessible α-helix driven by stronger hydrophobic interactions induces a rearrangement of the cap domain, displaying a "tic-tac-toe" activation feature that is important for stabilizing the dimer interface and facilitating the formation of hydrophobic pockets. In addition, the electrostatic potential surface analysis illustrates that the weaker electrostatic repulsion (Lys and Arg) in the dimer interface at high temperatures is also a key factor for dimer stabilization. Altogether, our results can provide molecular-level insight into the dimer formation process of hyperthermophilic esterase and would be useful to understand the enzymatic specificity of α/β-hydrolase.

Two Layers of Computational Screening on Silaborane‐based Clusters Filter Ca(SiB11H11CH3)2 as the Promising Electrolyte for Calcium‐Ion Batteries

AbstractCalcium‐ion batteries (CIBs) are promising energy storage systems, but the unavailability of adept electrolytes has hindered their development. In this work, a range of silaborane clusters ( ; n=5–15) were investigated using density functional theory (DFT) at ωB97XD3/6‐311+G(d,p) level of theory. The vertical detachment energy (VDE), electrochemical stability window (ESW) and binding energy (BE) of the silaboranes were computed at the same level of DFT. A methodology based on molecular electrostatic potential surface analysis was designed to locate the most suitable binding site for calcium ions on the clusters. DFT results show that the SiB11 cluster turns out to be superior to other candidates. Effect of substitution on silaboranes ( R− R=−CH3, −NCS, −CF3, −F and −Cl) was computed. −NCS and −CF3 substituted SiB11 ions were found to be the best from DFT. Ab initio molecular dynamics (AIMD) studies were performed to explore the interactions between silaborane‐based electrolytes and the Ca anode. AIMD results highlight the decomposition of −NCS and −CF3 substituted SiB11 on Ca anode. DFT and AIMD studies reveal that −CH3 substituted silaborane‐based Ca‐salt (Ca(SiB11H11CH3)2) is the promising electrolyte for CIBs.

Linking quinoline ring to 5-nitrofuran moiety via sulfonyl hydrazone bridge: Synthesis, structural characterization, DFT studies, and evaluation of antibacterial and antifungal activity

In the present work, we report the synthesis, structural characterization, and computational studies of (E)-N'-((5-nitrofuran-2-yl)methylene)quinoline-8-sulfonohydrazide (QNF) as a potential antimicrobial drug candidate. To design the target molecule, we utilized a molecular hybridization technique that connects two antimicrobial pharmacophores (quinoline and 5-nitrofuran rings) with a sulfonyl hydrazone moiety. QNF was synthesized by the condensation of quinoline-8-sulfonohydrazide with 5-nitrofuran-2-carbaldehyde, and characterized by various spectral techniques including single-crystal X-ray crystallography. QNF was extensively evaluated for its antibacterial and antifungal activity. The inhibition capacity of QNF on Candida albicans filamentation and biofilm formation was further investigated. Biofilm inhibition of QNF against C. albicans was supported by molecular docking studies in the binding site of agglutinin-like sequence 3 (Als3). Drug-like profile of QNF was confirmed by in silico calculation of its significant physicochemical properties. Additionally, the optimized geometrical structure, natural bond orbital calculations, frontier molecular orbital and molecular electrostatic potential analysis of QNF were carried out using the density functional theory method at the B3LYP with 6–31+G(d,p) basis set. The predictions of 1H and 13C NMR chemical shift values were performed using the gauge-independent atomic orbital method. Structural parameters and NMR values obtained experimentally were compared with the calculated values.

A novel salt and condensate–resistant foam co-stabilized by mixtures of surfactants and citric acid for gas well deliquification

Aged gas wells are often blocked by the accumulation of liquids, which can be removed by the injection of foaming surfactant mixtures. In this study, a compound foam stabilized by a quaternary mixture (alkyl amidoamine (amine), citric acid (acid), α–olefin sulfonate (AOS) and lauramidopropyl betaines (LAPB)) was firstly developed with the Waring blender method. The liquid unloading performance of this compound foam was then investigated to estimate its application potential under various condensate fraction, salinity and temperature conditions. At a condensate content range of 20 %–40 %, the amine/acid/AOS/LAPB foam is particularly effective in unloading the liquids. However, salinity was found to reduce the foaming efficiency (referred to as the ratio of the mass of the formed foam to that of the original liquid) and liquid unloading performance of the amine/acid/AOS/LAPB foam, which could be overcome through the addition of a chelator, namely nitrilotriacetic acid trisodium salt (NTA). Temperatures higher than 60 °C enhanced the performance of the amine/acid/AOS/LAPB foam. Synergistic effects within the quaternary mixture were confirmed by surface tension measurements, morphological observation, interaction energy calculation and the electrostatic potential analysis. The present results suggested that the amine/acid/AOS/LAPB mixture may be of use in relieving liquid loading of gas wells.

Synthesis, crystal structure, properties, and theoretical studies of novel tetra-nuclear copper(II) salamo-like complex containing four- and five-coordinated geometries

A novel tetra-nuclear Cu(II) salamo-like complex containing four- and five-coordinated Cu(II) atoms, [Cu4(L)2(MeOH)2]·2MeOH was synthesized and characterized structurally. The single crystal X-ray diffraction analysis indicated the Cu(II) complex is a triclinic system, including four Cu(II) atoms and two completely deprotonated ligand (L)4− units, forming an asymmetric geometric structure. Specifically, Cu2 and Cu4 atoms are located in the N2O2 cavities of two different ligand (L)4− units, respectively, and coordinate with one methanol molecule in the axial position to form five-coordinated tetragonal pyramid geometries. Meanwhile, Cu1 and Cu3 atoms respectively coordinate with four phenoxy atoms in the two ligand (L)4− units to form slightly distorted planar quadrilateral geometries with four coordination. The spectral properties of the ligand H4L and its Cu(II) complex were further analyzed by IR, UV–vis absorption spectra and fluorescence spectra. DFT calculation results showed that the Cu(II) complex has low optical reaction activity. In addition, the electrophilic and nucleophilic sites favorable for the formation of hydrogen bonds were found through molecular electrostatic potential analysis. Hirshfeld surface analysis identified the interactions in the crystal structure. In the Cu(II) complex, H···H/H···H interaction is dominant, indicating that there are a large number of hydrogen bonds in the complex. IRI analysis revealed that there are weak hydrogen bond interactions, all of which make the Cu(II) complex more stable.

Synthesis of thiourea-based ionic liquids for extracting Cu ions and their toxicity analysis

With the increasing pressure on environmental protection, it was important to achieve an environmentally friendly and efficient medium to separate Cu2+ from electroplating wastewater. Therefore, two thiourea based hydrophobic ILs were screened and synthesized, which could be used as efficient extractants to extract Cu2+ by introducing ethyl and carboxyl groups as functional groups. A three-step method was adopted, then its structure was characterized. Meanwhile, the extraction experiments were optimized, and the extraction mechanism was explored by electrostatic potential analysis and FT-IR characterization. The extraction efficiency (E) of the adopted ILs reached to 96% and 99%, respectively, under 298.15 K and the ratio of extractant to solution to be extracted 1:50. The circulation extraction was investigated under the optimal conditions, it was proved that the adopted ILs had good separation result. Meanwhile, Pseudokirchneriella subcapitata was selected as the object of ILs toxicity test. The values of the concentration for 50% of maximal effect (EC50) were 1-(3-isopropylthiourea propyl) imidazole hexafluorophosphate ([HIPSM][PF6]): 79.09 mg/L and 1-(3-isopropyl thiourea carboxyethyl) imidazole hexafluorophosphate ([ITPSCM][PF6]): 177.5 mg/L, respectively. σ-profile polarity analysis was adopted to judge the change of interaction between ILs and non-polar biofilm and deduced the principle of toxicity reduction. The results showed that the introduction of carboxyl group not only improved the E, but also reduced the ecological toxicity of the adopted ILs, making the adopted ILs more environmentally friendly.

Coordination-Driven Salamo-Salen-Salamo-Type Multinuclear Transition Metal(II) Complexes: Synthesis, Structure, Luminescence, Transformation of Configuration, and Nuclearity Induced by the Acetylacetone Anion.

A flexible polydentate Salamo-Salen-Salamo hybrid ligand H4L was designed and synthesized, which has rich pockets (salamo and salen pockets) so that it may have fascinating coordination patterns with transition metal(II) ions. Four multinuclear transition metal(II) complexes, novel butterfly-shaped homotetranuclear [Ni4(L)(μ1-OAc)2(μ1,3-OAc)2(H2O)0.5(CH3CH2OH)3.5]·4CH3CH2OH (1), helical homotrinuclear [Zn3(L)(μ1-OAc)2]·2CH3CH2OH (2), double-helical homotrinuclear [Cu2(H2L)2]·2CH3CN (3), and mononuclear [Ni(H2L)]·1.5CH3COCH3 (4), have been synthesized and characterized by single-crystal X-ray diffraction. The effects of different anions [OAc- and (O2C5H7)2-] on the complexation behavior of H4L with transition metal(II) ions were studied by UV-vis spectrophotometry. The fluorescent properties of the four complexes were studied with zebrafish, which are expected to be a potential light-emitting material. Ultimately, interaction region indicator (IRI) valuations, Hirshfeld surface analyses, density functional theory (DFT & TD-DFT), electrostatic potential analyses (ESP), and simulations were carried out to further demonstrate the weak interactions and electronic properties of the free ligand and its four complexes.

Crystal growth, structural insights, spectral, Z-scan, N[sbnd]H…O hydrogen bonding interaction and non-linear optical properties of the novelly synthesized 2-aminopyridinium cyanoacetate crystal

A novel organic single crystal 2-aminopyridinium cyanoacetate (2ACY) was synthesized and analysed by using UV–Vis, FT-IR, FT-Raman and single crystal X-ray diffraction experiments. Optically transparent and defect free crystal was grown from aqueous solution by slow evaporation technique at room temperature. All theoretical computations were carried out using the density functional theory (DFT) B3LYP approach using the basis set of 6–31+G(D). The grown crystal exhibits good optical transmittance in the UV–visible spectral analysis. The thermal behaviour of the 2ACY crystal has been analysed by TG/DTA analysis. Besides, the intermolecular interactions have been inquired and revealed by NBO analysis. Intermolecular contacts and molecular surface contours were analysed by using Hirshfeld and 2D fingerprint plot analysis. Topological analysis of electron localization function (ELF), localized orbital locator (LOL) and reduced density gradient(RDG) were evaluated. Additionally molecular electrostatic potential (MEP), HOMO-LUMO and charge analysis of the title compound have been investigated. The fluorescence behaviour of 2ACY crystal has been analysed in visible region and red colour emission is evidenced at 610 nm. The outcome of SXRD, UV-visible, TG/DTA, NLO, LDT and Z-scan values were compared with earlier reported compounds and amongst which the analysed compound 2ACY show good NLO activity. The occurrence of protonated intermolecular NH…O hydrogen bonding interaction liable for the nonlinear optical activity and it was projected using theoretical along with experimental techniques.

Degradation of methylene blue using a novel gas-liquid hybrid DDBD reactor: Performance and pathways

A novel gas-liquid hybrid double dielectric barrier discharge (DDBD) reactor with coaxial cylinder configuration was developed for the degradation of methylene blue (MB) in this study. In this DDBD reactor, the reactive species generation occurred in the gas-phase discharge, directly in the liquid, and in the mixture of the working gas bubbles and the liquid, which could effectively increase the contact area between the active substance and MB molecules/intermediates, resulting in an excellent MB degradation efficiency and mineralization (COD and TOC). The electrostatic field simulation analysis by Comsol was carried out to determine the appropriate structural parameters of the DDBD reactor. The effect of discharge voltage, air flow rate, pH, and initial concentration on MB degradation was evaluated. Besides, major oxide species, ·OH, the dissolved O3 and H2O2 generated in this DDBD reactor were determined. Moreover, major MB degradation intermediates were identified by LC-MS, based on which, possible degradation pathways of MB were proposed.

Methimazole and propylthiouracil design as a drug for anti-graves' disease: Structural studies, Hirshfeld surface analysis, DFT calculations, molecular docking, molecular dynamics simulations, and design as a drug for anti-graves' disease

Methimazole (MMI) and propylthiouracil (PTU), two commonly used anti-Graves' disease drugs, were studied using density functional theory (DFT) with the B3LYP approach and 6–311G(d,p) as the basis set. Molecular electrostatic potential (MEP), Hirshfeld investigations, and interactions energy analysis (IEA) were used to study the surface of the compounds to identify the various reactive surfaces which are essential for determining a variety of biological activities. Using an in-silico designing technique, fifteen new compounds with enhanced activity and docking scores were developed on the basis of information acquired from the standard drugs (MMI and PTU). These novel compounds featured improved activity and docking score results. Furthermore, molecular dynamics simulations were carried out on the standard drugs as well as the compound D10 with the highest binding affinity using protein 5hpw. In addition to this, the NBOs, FT-IR, and FT-Raman spectra of D10, as well as some of its thermochemistry, were reported and examined. These findings may provide useful information for future development.

Structural basis for fluorine substitution on a new naphthalene–chalcone analog

AbstractFluorinated chalcones are organic compounds with diverse biological activities and are of interest for drug development due to their improved properties, such as lipophilicity, bioavailability, and metabolic stability. Therefore, the correlation between structure and properties is fundamental to discover the potential use on pharmaceutical and technological applications. In this sense, we synthesized and characterized a novel fluorinated chalcone (E)-1-(4-fluorophenyl)-3-(naphthalen-1-yl)prop-2-en-1-one (FCH), and compared its supramolecular arrangement and topological analysis with a chalcone (E)-1-(4-hydroxyphenyl)-3-(naphthalen-1-yl)prop-2-en-1-one (HCH). The molecular electrostatic potential, QTAIM, and frontier molecular orbitals of both chalcones were investigated using the M06-2X/6-311++G(d,p) level of theory. Our findings show that the FCH exhibits a herringbone packing with intermolecular interactions of C–H⋯F and C–H⋯π, while the HCH assumes a staircase packing coordinated by O–H⋯O and π⋯π intermolecular interactions. Furthermore, the electrostatic potential analysis shows that FCH is susceptible to electrophilic attack, while HCH is susceptible to nucleophilic attack. Finally, the structural basis analysis for both chalcones indicated that FCH has a higher lipophilicity than HCH due to the stronger hydrogen bond of HCH with water.

Two-dimensional ZnO/ZrXY (X, Y = Br, Cl and F) van der Waals heterostructures as promising photocatalysts for high efficiency water splitting

In recent years, hydrogen (H2) energy has been attracting extensive research attention as a clean resource as the energy shortage has become increasingly prominent. Two-dimensional (2D) materials exhibit superior physical and chemical properties compared to their conventional counterparts, hence demonstrating considerable advantages in the water-splitting photocatalyst application. Based on first principle calculations, in this work, monolayered ZnO and ZrXY (X, Y = Br, Cl and F) are combined to form vdW heterostructures and investigate their structural, optical and electronic properties for evaluating their ability to split water photocatalytically. Based on our calculations by two different models (model I and II), ZnO/ZrXY vdW heterostructures exhibit indirect band gaps with a type II band alignment, which benefits the effective spatial separation of photogenerated charge carriers. Bader charge, Charge density difference, and Planner-averaged electrostatic potential analysis suggest that photogenerated charges flow from ZrXY to the ZnO layer are effected by the dipole interface, which prevents the recombination of photogenerated charge carrier and promotes their separation and transfer. Moreover, calculations for optical properties in relation to the dielectric constant's imaginary part indicate that all primary excitation peaks are located in the visible light region, and a red-shift is also observed in ZnO/ZrXY vdW heterostructures. In addition, the band edges of ZnO/ZrXY vdW heterostructures span water redox potentials, which satisfy the requirement of overall photocatalytic water splitting.

Investigation of nonlinear optical responses of organic derivative of imidazole: imidazole-2-carboxaldehyde

Abstract In the present work, we explored the nonlinear optical properties of imidazole-2-carboxaldehyde, which is an aromatic derivative of imidazole. Optimization has been performed for imidazole-2-carboxaldehyde using density functional theory with a B3LYP/6-311G basis set. To check the possible charge transfer, Mulliken charge analysis and molecular electrostatic potential analysis was performed. The chemical reactivity of the probe molecule was investigated by calculating different frontier molecular orbital parameters such that energy gap, ionization potential, electron affinity, chemical potential, electronegativity, softness, and hardness. Raman, Fourier transform infrared, and nuclear magnetic resonance analysis was also performed to study vibrational properties and UV–vis was performed to study the electronic properties of the compound. A high value of dipole moment (μ total), polarizability (α), first-order hyperpolarizability (β), and Raman activity validates the NLO behavior of the compound. Thus, the performed computational study validates a strong candidature of imidazole-2-carboxaldehyde to be used as a non-linear optically active material in the future.

Theoretical exploration and experimental regulation of the degradation of Δ9-tetrahydrocannabinol in hemp seed oil by density functional theory

Δ9-tetrahydrocannabinol (Δ9-THC) in hemp seed oil is a psychoactive cannabinoid, and the content of Δ9-THC can be reduced. Density functional theory (DFT) was used to simulate the degradation path of Δ9-THC, and the ultrasonic treatment was used to degrade the Δ9-THC in hemp seed oil. Results found that the reaction of Δ9-THC degradation to cannabinol (CBN) was a spontaneous exothermic reaction, which required a certain amount of external energy to initiate reaction process. Through the surface electrostatic potential analysis, the minimum value of electrostatic potential of Δ9-THC was −37.68 kcal/mol, and the maximum value was 40.98 kcal/mol. The frontier molecular orbitals analysis found that the energy level difference of Δ9-THC was lower than that of CBN, indicating that the reactivity of Δ9-THC was stronger. The degradation process of Δ9-THC could be divided into two stages, which needed to cross the reaction energy barriers of 3197.40 and 3087.24 kJ/mol, respectively. Ultrasonic treatment was used to degrade Δ9-THC standard solution, it was found that Δ9-THC can be effectively degraded into CBN through intermediate. Subsequently, ultrasonic technology was applied to hemp seed oil, under the conditions of ultrasonic power 150 W and ultrasonic time 21 min, the Δ9-THC was degraded to 10.00 mg/kg.

Non-linear optical behavior of gold and silver clusters adsorbed on 2,9-Dimethylquinacridone

In the present work, the adsorption of silver (Ag3) and gold (Au3) clusters on 2,9-Dimethylquinacridone (2,9-DMQA) was examined by using density functional theory. The variation of structural parameters was observed after the introduction of Ag3 and Au3 clusters. The interactions between the clusters and 2,9-DMQA induced variations in the structural parameters and electronic properties. The involvement of clusters in inducing the intramolecular charge transfer was confirmed by electrostatic potential surface and charge analysis. The electronic properties of the complex were studied by absorption and emission spectra. The adsorption of the Ag3 and Au3 clusters over the 2,9-DMQA leads to an enormous rise in the hyperpolarizability of the complexes. Thus, the Ag3 and Au3 clusters adsorbed 2,9-DMQA gave enhanced nonlinear optical activity.

Spectroscopic Characterization, Quantum Chemical and Molecular Docking Studies on 1-Chloroanthraquinone: A Novel Oral Squamous Cell Carcinoma Drug

Anthraquinone derivatives are well recognized for their anticancer activities and pharmacological properties. In the present study, comprehensive theoretical and experimental FT-IR, FT-Raman, and UV-visible spectroscopic studies on the 1-Chloroanthraquinone (CAQ) molecule were carried out. The optimized molecular structure and harmonic vibrational frequencies was calculated using Gaussian 09 program. The experimental and calculated vibrational wavenumbers were assigned, which correlated well with the previous literature. The UV-visible absorption spectrum of the CAQ molecule was computed in the liquid phase (ethanol), which exhibits n–π* electronic transition, and the results were compared with the observed UV-visible spectrum. From the frontier molecular orbital analysis, the calculated energy gap value (4.03 eV) indicates that the CAQ molecule has a stable structure and the value was comparable with the band gap energy value of the reported bioactive molecules. The electron back donation from the carbonyl group oxygen atom to the benzene ring was identified using Mulliken atomic charge distribution analysis. Molecular electrostatic potential surface analysis confirms the reactive sites of the molecule. The natural bond orbital analysis validates electron back donation from the carbonyl group oxygen atom to the benzene ring of the CAQ molecule. The molecular docking analysis results that the CAQ molecule acts as a good inhibitor of histone deacetylase 6 (HDAC6) protein. HDAC6 protein is associated with oral squamous cell carcinoma. Thus, the present study paves the way for designing novel drugs for the treatment of oral squamous cell carcinoma.