LANL2DZ Basis Set Research Articles

Structural and spectroscopic analysis of L‐Proline monomer and dimer by DFT approach

AbstractIn this work we have analyzed the Fourier Transform Infrared (FTIR), Raman and Surface Enhanced Raman Spectra (SERS) of L‐Proline. The molecule under consideration L‐Proline in monomer and dimer states were optimized using DFT/B3LYP and DFT/M06‐2X methods with 6‐31G (d,p) basis set. In order to correlate the experimental SERS spectra we have calculated the Raman spectra of L‐Proline monomer and dimer with silver (Ag) clusters using Density Functional Theory (DFT) with B3LYP functional and LANL2DZ basis set. The vibrational spectra were interpreted by using vibrational energy distribution analysis (VEDA) program and potential Energy Distribution (PED) analysis of the vibrational modes have been performed to have a clear picture of the fragments of different states of the molecule. The equilibrium molecular geometry, harmonic vibrational wavenumbers, Frontier molecular orbitals, Mulliken charges, energy parameters and various bonding features have also been computed.

Affinities to Oxaliplatin: Vitamins from B Group vs. Nucleobases.

Oxaliplatin, similar to Cisplatin, exhibits anticancer activity by interacting with DNA and inducing programmed cell death. It is biotransformed through a number of spontaneous and non-enzymatic processes. In this way, several transient reactive species are formed, including dichloro-, monochloro-, and diaqua-DACH platin, which can complex with DNA and other macromolecules. The molecular level suggests that such interactions can also take place with vitamins containing aromatic rings with lone pair orbitals. Theoretical and experimental studies were performed to investigate interactions of vitamins from the B group with Oxaliplatin, and the results were compared with values characterizing native purines. Quantum-chemical simulations were carried out at the B3LYP/6-31G(d,p) level, with the LANL2DZ basis set representing atomic orbitals of platinum atom, and at the MN15/def2-TZVP levels of theory with the use of Polarizable Continuum Model (IEF-PCM formulation) and water as a solvent. Additionally, time-dependent density functional theory (TD-DFT) was employed to study molecular properties in the electronic excited state. Interactions of vitamins and Oxaliplatin were investigated using UV-Vis spectroscopy. Values of the free energy (ΔGr) indicate spontaneous reactions with monoaqua [PtH2OClDACH]+ and diaqua [Pt(H2O)2DACH]2+ derivatives of Oxaliplatin. However, diaqua derivatives were found to be preferable. The free energy (ΔGr) values obtained for vitamins from the B group indicate lower affinity of Oxaliplatin compared with values characterizing complexes formed by guanine, adenine, and cytosine. The exception is the monoaqua form of vitamin B1 (thiamine) at the MN15/def2-TZVP levels of calculations. An application of atoms in molecules (AIM) theory revealed non-covalent interactions present in the complexes studied. The comparison of computed and experimental spectroscopic properties showed a good agreement.

Novel thiadiazole‐derived Schiff base ligand and its transition metal complexes: Thermal behaviour, theoretical study, chemo‐sensor, antimicrobial, antidiabetic and anticancer activity

Novel thiadiazole‐based Schiff base ligand (L) and their Co(II), Ni(II), Cu(II) and Zn(II) metal complexes have been prepared and characterized using elemental analysis, IR, 1H‐NMR, 13C‐NMR, UV‐vis spectroscopy, EPR, thermal analysis, magnetic moment and conductometric measurements. Based on the above studies, the metal complexes were found to exhibit octahedral geometry except that of Zn(II) complex, which is tetrahedral. The thermal stability and the presence of coordinated water molecules of the metal complexes were investigated by thermogravimetric analysis. Geometry optimization of the ligand and its Zn(II) complex was performed using B3LYP functional with LANL2DZ basis set. The HOMO–LUMO energy gap, molecular properties, NLO, polarizability and MEP were theoretically calculated. The fluorescence spectra of the ligand revealed that the sensor could detect K+ ions over the pool of other metal ions. The Schiff base ligand and its metal complexes have been screened for their antimicrobial activity against different bacterial and fungal species using inhibition zone technique and by well diffusion methods. The results revealed that metal complexes have more activity than that of the ligand. The anticancer activities of Co(II) and Cu(II) complexes have been studied towards breast cancer (MCF‐7) cell lines. The Co(II) and Cu(II) complexes have also been evaluated for in vitro α‐amylase inhibitory activity.

Structural characterization (XRD, FTIR) and magnetic studies of Cd(II)-Sulfamethoxazole-2,2′-bipyridine: DFT and Hirshfeld Surface Analysis

New cadmium(II) complex have been synthesized by the reaction of nitrogen donor ligand sulfamethoxazole (smtxH: 4-amino-N-(5-methylisoxazol-3-yl)benzenesulfonamide) and nötr ligand 2,2′-bipyridine (bipy). The resulting compound is a neutral [The Cd(smtx)2(bipy)2•H2O] complex. The structure of the metal complex have been elucidated by single-crystal X-ray diffraction. The central Cd(II) ion is coordinated by two monodentate sulfamethoxazole anions together with two bidentate bipy ligand forming the octahedral geometry. The theoretical optimized geometrical parameters is calculated by using the Density Functional Theory (DFT) with the B3LYP method at 6–311G(d,p) bases set. Observed and calculated IR frequencies were found to be agreement. Hirshfeld surface analysis has been performed to study the nature of intermolecular interactions within the crystal structure and the finger- print plots, molecular surface contours. Molecular orbital coefficients were obtained using EPR and UV data. The thermal behavior of compound has been investigated.Cd(II)-smtx-2,2′-bipyridine molecule was synthesized. The complex was characterized by FT-IR, XRD. Molecular orbital coefficients were calculated using data from EPR and UV. With the help of Hirshfeld surface analysis, the intermolecular interactions in the crystal structure were interpreted by reducing them to fingerprint graphics. The TGA curves of compound have been examined. Structural and optical properties of the complex were further analyzed by quantum chemical calculations performed using DFT-TDDFT/B3LYP method in combination with LANL2DZ basis set.

Anticancer property and normal cell toxicity profile of pyrrolidine‐based platinum (II) complexes: Their DNA, BSA interaction, and molecular docking

The bioactivity and cytotoxic property of cis‐[Pt (AEP)Cl2] (C‐1); [Pt (AEP)(OH2)2](NO3)2 (C‐2); [Pt (AEP)(GSH) (C‐3)]; and [Pt (AEP)(DL‐meth)]2+(C‐4) (where AEP = 1‐[2‐Aminoethyl] pyrrolidine; GSH = Glutathione; DL‐meth = DL‐methionine) were extensively investigated to find out the more active and less toxic anticancer lead molecules. Spectroscopically characterized Pt (II) complexes (C‐1 to C‐4) were under investigation for their anticancer activity and bio‐molecular interaction with DNA and BSA. The binding property of the complexes toward DNA and BSA were evaluated by UV–Vis, fluorescence spectroscopy, gel electrophoresis, cyclic voltammetry (CV), circular dichroism (CD), and viscometric methods for their pharmacokinetic and pharmacodynamics importance. The BSA binding activity as well as their “Drug reservoir” property of Pt (II) complexes were highlighted for their biological significance. Furthermore, to assess the manner of interaction and also binding strength of the complexes with DNA and BSA molecule, a theoretical approach by molecular docking was performed, utilizing the optimized structure of the complexes. Structural optimization has been performed with density functional theory (DFT) correlation functional (B3LYP) at 6‐31G + (d, p) and LANL2DZ basis set was used for C, N, H, O, S, and metal, respectively. In vitro anticancer activity and level of ROS generation in presence of each complex were explored on A549 cancer cell as well as normal human cell lines HEK293, and their potential cytotoxic property was observed as compared to well‐known recognized anticancer cisplatin.

Density Functional Theory Study on NiNx (x = 1, 2, 3, 4) Catalytic Hydrogenation of Acetylene.

In this study, using the application of density functional theory, the mechanism of graphene-NiNx (x = 1, 2, 3, 4) series non-noble metal catalysts in acetylene hydrogenation was examined under the B3LYP/6-31G** approach. With the DFT-D3 density functional dispersion correction, the effective core pseudopotential basis set of LANL2DZ was applied to metallic Ni atoms. The reaction energy barriers of NiNx catalysts are different from the co-adsorption structure during the catalytic hydrogenation of graphene-NiNx (x = 1, 2, 3, 4). The calculated results showed that the energy barrier and selectivity of graphene-NiN4 for ethylene production were 25.24 kcal/mol and 26.35 kcal/mol, respectively. The low energy barrier and high activity characteristics showed excellent catalytic performance of the catalyst. Therefore, graphene-NiN4 provides an idea for the direction of catalytic hydrogenation.

Nonlinear optical and quantum chemical studies of Palladium benzimidazole Schiff base complex

This article presents the linear and nonlinear optics and density functional theory studies of a Palladium complex with a benzimidazole-based Schiff base. Linear absorption of the complex has been studied using a UV–Vis absorption spectrometer. Optical nonlinearity and thereby the optical limiting performance of the complex has been deliberated experimentally using a Z-scan method with a continuum wave laser of wavelength 532 nm. The NLO investigation of the complex demonstrated significant nonlinear absorption (βeff = 4.64–27.23 × 10−2 cm/W) with an imaginary part of nonlinear optical susceptibility of the third-order (Imχ(3) = 1.28–7.49 × 10−5 esu) and nonlinear refraction (n2 = 5.46–12.3 × 10−7 cm2/W) with real part of nonlinear optical susceptibility of the third-order (Reχ(3) = 3.55–8.00 × 10−5 esu). The large nonlinear absorption displayed superior optical power limiting characteristics with a threshold and clapping level of 115 W/cm2 and 35 W/cm2respectively. Theoretical studies are performed for Palladium benzimidazole Schiff base complex within Density Functional Theory (DFT) framework, using hybrid exchange-correlation B3LYP with basis set LANL2DZ. DFT-based descriptors are computed viz. energy gap between HOMO-LUMO, electronegativity, electrophilicity index, molecular hardness, and softness. Result reveals that the bond length between Pd–O is small as compared to Pd–Cl and Pd–N.

Determination of the standard enthalpy of formation of iodine compounds through the G2 and G3(MP2)//B3-SBK theories.

The domain of application of the G3(MP2)//B3-SBK theory was expanded, and its efficiency was evaluated to determinate enthalpies of formation of forty-one iodine compounds. The results were compared to those obtained with the G2 theory for the same set of molecules. The G3(MP2)//B3-SBK theory showed a mean deviation and deviation standard equal to 3.7kcalmol-1 and 6.0kcalmol-1, respectively. The G2 theory (mean deviation = 3.1kcalmol-1 and standard deviation = 4.9kcalmol-1) presented a lower error and standard deviation, but at a significantly higher computational cost. For a more complete evaluation, as a secondary part of the work, it also used different functionals B3LYP, M06-2X, WB97XD, and MP2 method with four different basis sets 6-311G(d,p), LANL2DZ, jorge-ADZP, and CEP-31G(d). The best density functional/basis set combination was obtained with M06-2X/CEP-31G(d) among the three mentioned functionals. However, the produced mean deviation is significant and equal to 17.3kcalmol-1, with a standard deviation equal to 23.0kcalmol-1. The 6-311G(d,p) basis achieved the best performance with the MP2 method, generating an equally significant mean deviation of 12.8kcalmol-1 with a standard deviation equal to 18.7kcalmol-1.

Synthesis and experimental/theoretical evaluation of an efficient Calix[4]arene based sensor for selective detection of Pt2+ ion

In this study, a novel derivative of functionalised Calix[4]arene chem-sensor (4-amino thiazole 2-thiol-Calix[4]arene (R-Sensor)) was investigated, using the FT-IR spectroscopic method. Fluorescent properties and the ability to detect the sensor toward different cation ions in acetonitrile aqueous solution were investigated using the UV–Vis method, fluorescence titration, and Job’s plot method. The results showed that among the studied cations, the presence of Pt(II) has a greater effect on the intensity and wavelength of the emission. In addition, the optimised structure and electronic properties of this R-sensor was studied, using the density functional theory (DFT), B3LYP and M062X methods, at the LANL2DZ (6-311 + G/CPCM and 6-311++G/CPCM) basis set, and quantum theory of atoms in molecules (QTAIM). The results of these theoretical-computational studies showed that the selectivity of this sensor is related to its molecular structure, electronic properties, and surface electrostatic properties. Theoretical studies have shown that electronic properties such as energy gap, sensitivity, and charge/energy transfer change dramatically in the presence of Pt(II) cations. In addition, the molecular competitive tests showed that this R-sensor could be a good candidate for monitoring/measuring Pt(II) in physiological samples/ environments.

DFT investigation of graphene quantum dot-Ixora floral natural dye (GQD-NDIX) nanocomposites as visible light harvesters in dye-sensitized solar cells

As reported, the power conversion efficiencies of photosensitized solar cells with the four natural dyes from Ixora floral (NDIXs) were less than 1%, resulting from poor absorption of light in the visible (Vis) and near infrared (NIR) regions. The four NDIXs are aurone (ND1), pelargonidin (ND2), cyanidin (ND3) and malvidin (ND4). In this work, the study was conducted to investigate the effect of hybridizing the four NDIXs with graphene quantum dots (GQDs). The four NDIXs were studied computationally at the DFT/TDDFT with B3LYP/CAM-B3LYP functionals and 6-31G(d,p)/LANL2DZ basis sets all with the C-PCM solvation model. All the calculated parameters preferred the GQD-NDIX nanocomposites (NCs). NCs have appropriate HOMO and LUMO energy levels, absorbed light in the Vis region with a much higher light harvesting efficiency (by a difference not less than 5%), and significantly improve the intramolecular charge transfer (IACT) property necessary for efficient electron injection. Among the three configurations of the possible adsorption systems of NCs on TiO2, the NCs adsorbed on TiO2 through a covalent interaction between the NDs and TiO2 and not by the GQD adsorbed on TiO2 were evident by comparing the adsorption energies of different adsorption systems (the difference is not less than 0.7 eV). The optical properties of isolated dyes/nanocomposites were compared and discussed, and the optical properties of TiO2 adsorbed systems were calculated and discussed. The nonlinear optical (NLO) properties were compared and proved to be significantly enhanced and thus the IACT abilities in the adsorbed systems. This work can be used as a useful source for developing GQD-NDIX photosensitizers as efficient visible light harvesters in DSSC applications.

Third-order nonlinear optical studies of Bis(4-methylbenzylammonium) tetrachloridocuprate metal-organic crystal with optical limiting behavior: Experimental and theoretical investigations

The metal-organic nonlinear optical (NLO) compound Bis(4-methylbenzylammonium) tetrachloridocuprate (4MBA) was synthesized and grown by the slow evaporation method. X-ray crystal analysis revealed the crystal structure and conformation. Density functional theory (DFT) at B3PW91/LanL2DZ basis set level was applied and computed the optimized geometry, electronic structure, vibrational spectra, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), and natural bonding orbitals (NBO). UV–Vis-NIR spectroscopic measurements revealed the optical transparency range from 310 to 1100 nm and excited-state properties. The thermal behavior and stability of the compound were analyzed using TGA/DTA, and the suitability of the optical material is weighed. The dielectric parameters and AC conductivity were investigated as a function of frequency and temperature. Second-harmonic generation (SHG) efficiency was measured using the Kurtz and Perry powder approach and found 4MBA to be 0.8 times the KDP. The nonlinear refractive index (n2), nonlinear optical absorption (β) and third-order nonlinear optical susceptibility (χ(3)) measured values are 1.548 × 10−9 cm2 W−1, 0.0538 × 10−4 cm W−1, and 6.049 × 10−8 esu respectively, and shows that the 4MBA molecule is a third-order nonlinear optical material. The optical limiting threshold value is determined as 7.632 × 103 W cm2 for 532 nm continuous-wave laser, representing that the 4MBA is a strong candidate for the optical limiting application. The static and dynamic nonlinear optical parameters were computed with three different functions including B3PW91, M06 and PBE0 using LanL2DZ basis set. The outcomes revealed that the 4MBA molecule under study might be a promising NLO material for frequency generators and optical limiters applications.

Experimental and computational investigation of a novel organic cation hexachlorostannate (IV) material (C7H9N2O)2(SnCl6)

A novel organic–inorganic hybrid material (C7H9N2O)2(SnCl6) was obtained by synthetic reaction in aqueous solution. The crystallographic study shows that the investigated compound crystallizes in the triclinic system with P-1 space group. Its unit cell dimensions are a = 7.0859 (7) Å, b = 9.0553 (9) Å, c = 9.1442 (8) Å, a = 81.152(8) Å3, b = 87.126 (8) Å3, c = 67.977 (10) Å3 with V = 537, 43(25) and Z = 2.The three-dimensional framework and the stability of the crystal are insured by N−H⋯Cl, N−H⋯O and C−H⋯O hydrogen bonds and Cg⋯Cg (π⋯π) stacking. The vibrational absorption bands were recorded by IR spectroscopy and have been identified in relation to the crystal structure of a made-up (C7H9N2O)2(SnCl6) sample. The optical properties of the crystal were studied by using UV–visible absorption spectroscopy. The intermolecular interactions occurring in the crystal and their relative contributions in building the solid-state architecture, were quantified by using the three-dimensional Hirshfeld surfaces and two-dimensional fingerprint plots. In addition, the molecular geometries, vibrational frequencies of the compounds in the ground state have been performed using density functional theory (DFT) method, at B3LYP with 6-311g+(2d,2p) set for C, H, N, O, Cl atoms and LANL2DZ basis set for Sn atom.Topological AIM approaches and noncovalent interaction reduced density gradient (NCI-RDG) analyses and were pursued to generate a profound understanding of the structure-directing interactions in the compound. The NBO analysis was carried out to provide information about the delocalization of charge and energy density of atoms.

Quantum chemical hydrogenolysis strategy for elimination of heteroatoms in biomass homologous organic compounds based on oxolane and thiolane

Bio-oils obtained from biomass contain heteroatoms compounds, like oxolane and thiolane. It is quite difficult for industrialist to purify such refractory bio-oils. One of the efficient strategies for the elimination of heteroatoms is hydrogenolysis process, which results in the formation of H2O and H2S residues as by-products. In this work, quantum chemical studies have been used to analyse the reaction mechanism for the removal of hetero atoms (S and O) as H2O and H2S. We selected B3LYP functional of DFT with Pople's basis set 6-311G(d,p) for computing the hydrogenolysis steps without catalyst. LANL2DZ basis set, is used for studying hydrogenolysis steps involving AlCl3 and WS3H3+ as catalysts. All the reactions are analysed at the temperature of 600 K and pressure of 40 bars. Structural, thermodynamic, kinetic properties have been employed to study this process. The analysis of variations parameters during the hydrogenolysis process reveals that these two organic biomass compounds undergo sequential ring opening at C-X (X = O, S) bonds. Butanol and Butanethiol are obtained as a result of first hydrogenolysis process, and these compounds are converted to butane during second catalytic process while eliminating heteroatoms.

Spectroscopic and Molecular Docking Studies of Cu(II), Ni(II), Co(II), and Mn(II) Complexes with Anticonvulsant Therapeutic Agent Gabapentin.

New Cu(II), Ni(II), Co(II), and Mn(II) complexes of the gabapentin (Gpn) bidentate drug ligand were synthesized and studied using elemental analyses, melting temperatures, molar conductivity, UV–Vis, magnetic measurements, FTIR, and surface morphology (scanning (SEM) and transmission (TEM) electron microscopes).The gabapentin ligand was shown to form monobasic metal:ligand (1:1) stoichiometry complexes with the metal ions Cu(II), Ni(II), Co(II), and Mn(II). Molar conductance measurements in dimethyl-sulfoxide solvent with a concentration of 10−3 M correlated to a non-electrolytic character for all of the produced complexes. A deformed octahedral environment was proposed for all metal complexes. Through the nitrogen atom of the –NH2 group and the oxygen atom of the carboxylate group, the Gpn drug chelated as a bidentate ligand toward the Mn2+, Co2+, Ni2+, and Cu2+ metal ions. This coordination behavior was validated by spectroscopic, magnetic, and electronic spectra using the formulas of the [M(Gpn)(H2O)3(Cl)]·nH2O complexes (where n = 2–6).Transmission electron microscopy was used to examine the nanostructure of the produced gabapentin complexes. Molecular docking was utilized to investigate the comparative interaction between the Gpn drug and its four metal [Cu(II), Ni(II), Co(II), and Mn(II)] complexes as ligands using serotonin (6BQH) and dopamine (6CM4) receptors. AutoDock Vina results were further refined through molecular dynamics simulation, and molecular processes for receptor–ligand interactions were also studied. The B3LYP level of theory and LanL2DZ basis set was used for DFT (density functional theory) studies. The optimized geometries, along with the MEP map and HOMO → LUMO of the metal complexes, were studied.

Synthesis, Spectroscopic Characterization, Molecular Docking and in Vitro Cytotoxicity Evaluation Studies on 6-Methoxy-8-Nitroquinoline Hydrogen Sulphate: A Novel Cervical Cancer Drug

The 6-Methoxy-8-nitroquinoline hydrogen sulfate (6M8NQHS) molecule has been studied using density functional theory (DFT) with thorough and accurate vibrational and spectroscopic investigations, as well as experimental validation. FT-IR, FT-Raman, and UV-Vis spectroscopy techniques were used to characterize the synthesized 6M8NQHS sample. The optimized molecular structure and harmonic vibrational frequencies of the molecule were calculated using DFT/B3LYP method with a LANL2DZ basis set using the Gaussian 09 program. The computed and experimental vibrational wavenumbers were assigned. The UV-Vis spectrum absorption spectrum of the molecule was observed in the liquid phase (acetone) and also simulated, which shows the π to π* and n to π* electronic transitions of the molecule. Frontier molecular orbital research reveals the molecule’s molecular reactivity and kinetic stability. The molecule’s reactive site is confirmed by the Mulliken atomic charge distribution and molecular electrostatic potential surface analysis. The bioactivity of the molecule was demonstrated by the natural bond orbital analysis. Molecular docking analysis confirms that the 6M8NQHS molecule inhibits the action of human p38a Mitogen-activated protein kinase 14, which is linked to cervical cancer. In addition, the MTT assay was used to determine the in vitro cytotoxicity of the 6M8NQHS molecule against human cervical cancer cell lines (ME180) and human breast cancer cell lines (MDA MB 231), demonstrating that the title molecule inhibits the cervical cancer cell lines more than breast cancer cell lines. As a result, the current research paves the way for the creation of new drugs to treat cervical cancer.

A comparative DFT study of structural, electronic, thermodynamic, optical, and magnetic properties of TM (Ir, Pt, and Au) doped in small Tin (Sn5 & Sn6) clusters

ABSTRACT The geometric, electronic, thermodynamic, optical, and magnetic properties of Sn5 and Sn6 clusters after doping with transition metals (TM) – Gold, Platinum, and Iridium have been investigated. This investigation has been performed by employing density functional theory with B3LYP hybrid functional using LanL2DZ and SDD basis sets. It was observed that Pristine Sn5 / Sn6 clusters gain more stability and effectiveness after doping transition metals in middle and side positions. The TM doped Sn5 clusters are more stable chemically and energetically than TM doped Sn6 clusters whereas Sn4-Au-M cluster is more stable than other clusters. Imaginary frequency was not found for Sn4-Au-M cluster according to IR spectroscopy study. So, this cluster can be found naturally and possesses magnetic susceptibility. Also, Au-M doped Sn5 cluster is spontaneous and more stable thermodynamically. Due to preferable structural, electronic, thermodynamic, and magnetic properties, the optically active Sn4-Au-M cluster could be suitable for technological applications.

Intermolecular interaction study of Ag-amino acid biomolecular complex using vibrational spectroscopic techniques and density functional theory method

Nowadays, people are more healthy skin conscious which leads to a healthy and beneficial lifestyle. There are different skin products in the market and many are coming up according to consumer demand. In the present study, we have chosen three molecules D-Proline, TCA and Ag metal that are very much beneficial for the skin and synthesize their biomolecular complex. The study of their biomolecular complex at the atomic level shall help to produce potential drugs having high efficacy and fewer side effects. The present paper emphasizes the interaction study of silver (Ag) metal ions with amino acid D-Proline and the solute-solvent mixture of D-Proline and Trichloroacetic acid (TCA) under the Raman, FTIR and UV-Vis experimental techniques. The favourable binding sites of D-Proline, (D-Proline)Ag, (D-Proline)Ag2, D-Proline-TCA, (D-Proline-TCA)Ag and (D-Proline-TCA)Ag2 complexes are studied using the B3LYP method with a LANL2DZ basis set. The study includes electronic and molecular behaviour examined under MEP surface study, frontier molecular orbital analysis, NBO analysis, and AIM analysis to investigate the type of interactions between the metal and the ligand. The IEFPCM solvation model is undertaken to execute the UV-Vis simulation using methanol as solvent. BSSE method is carried out to provide an appropriate interacting environment. The complexes' drug-likeness properties and bioactivity score are studied to understand their bioactivity and pharmacokinetics. The Autodock tool is implemented to execute the molecular docking study of the complexes with the preferable binding sites of 1QCY collagen receptor.

Experimental and theoretical evaluation of N-pyridoxal-salicylic acid hydrazide derived copper(II) complex with 2-methylimidazole

This article deals with the experimental and theoretical evaluations of N-pyridoxal-salicylic acid hydrazide (H2pd-sah) 1 and its mixed-ligand copper(II) complex with 2-methylimidazole, [Cu(pd-sah)(MeImdH)] 2. The compounds were characterized based on spectral (UV/Vis. IR) methods, powder-XRD, elemental analysis, and molar conductivity measurements. Both compounds' molecular structure and charge analysis were computed through B3LYP with 6-311 G (d, p) and LANL2DZ basic set using the Gaussian 09 W program package. The time-dependent density functional theory (TD-DFT) approach is used in gas-phase electronic transitions of 2 using the LANL2DZ basis set. Also, the computed UV-Vis based upon TD-DFT results and IR spectra were simulated for comparison with the experimental ones. The molecular structure based on theoretical investigation reveals that compound 2 adopts a distorted square planer N2O2 coordination sphere around the Cu(II). The ONO donor atoms of hydrazone moiety and one nitrogen of 2-methylimidazole constitute the N2O2 basal plane. Moreover, the in-vitro antioxidant activity was evaluated by DPPH assay in both compounds. In addition, Molecular docking studies were performed to predict the binding interaction between compound 2 and the Human Serum Albumin HSA (PDB ID: 1H9Z). Communicated by Ramaswamy H. Sarma

Understanding the mechanism of thioguanine's binding to Ag6 and bimetallic (Ag3–Au3 and Ag3–Cu3) clusters

Using Ag6, Ag3Au3 and Ag3Cu3 clusters, density functional theory (DFT) methods were used to elucidate the interaction behavior of thione-containing thioguanine drug (TGN) on silver. The CAM-B3LYP functional with LANL2DZ basis set was used to study the different features and bonding qualities of resultant metal complexes. The drug molecule tends to anchor on the cluster with binding energies ranging from −16 to −23 kcal/mol. Due to the recovery time values and change in energy gap, the metal clusters can be turned into an electrical signal for detecting TGN. TGN-metal cluster interactions are reversible events, and a drug release mechanism has been postulated. As a result of a modest change in pH in tumor cells, the drug is able to detach from metal surfaces. Non-covalent interactions studies show that TGN's NH2 group is more important for hydrogen bonding, and the heterocyclic N and S atoms may play a role in weak interactions.

Synthesis, structural, photo-physical properties and DFT studies of some diarylheptanoids

In the present work, we have described the structures, photo-physical properties and DFT computations of some curcumin type diarylheptanoids (4a–c). These compounds were characterized by multi-spectroscopic techniques including X-ray single crystal of one of the intermediates (3a). The molecular geometries and structural features were configured by DFT -B3LYP/6-31G(d,p) calculations; however, combined 6-31G(d,p)/LANL2Dz basis sets (B3LYP/Gen) were employed in case of bromine and iodine derivatives. Compared to the native curcuminoids, these diarylheptanoids showed blue-shifted optical spectroscopic features in solution; aggregation enhanced emission properties were also noted. The incorporation of halogen atom enhanced thermal stability of the compounds. Aided by Cartesian coordinate displacement of the computed wavenumbers, we have suggested reliable vibrational assignments for the observed infrared fundamentals. The results of this study will be a valuable addition to the growing body of work on the properties of curcuminoids.