B3LYP Method Research Articles

Theoretical Investigations of Bioactive Substituted 2‐Amino‐3,5‐dicarbonitrile‐6‐thiopyridine Derivatives

AbstractThis study utilizes the density functional theory (DFT) (B3LYP method and 6–31 + G* basis set)‐based method to theoretically investigate substituted 2‐amino‐3,5‐dicarbonitrile‐6‐thiopyridine derivatives within a prevalent multicomponent reaction involving aldehyde, malononitrile, and thiophenol. Various reactivity descriptors, including frontier molecular orbitals, dipole moment, polarizability, and molecular electrostatic potential, are computed to understand the variations in reactivity and stability of these compounds. The results demonstrate the reliability of DFT‐derived descriptors in predicting chemical reactivity and provide valuable insights for further research and practical applications in the field of chemical reactivity and reaction mechanisms. Geometric parameters, along with thermodynamic variables, such as standard enthalpies (ΔH), entropies (ΔS), Gibbs free energy (ΔG), and global reactivity descriptors (ionization potential (I), electron affinity (A), chemical hardness (η), softness (σ), global softness (S), chemical potential (μ), global electrophilicity (ω), and nucleophilicity index (N), are calculated to gain insight into the dynamics of these interactions and variations in reactivity and stability.

Quantum computational, spectroscopic analysis, and molecular docking studies of 2-chloroethyl benzene

In this work, theoretical and experimental aspects of 2-chloroethyl benzene (2-CEB) were investigated and implemented for future investigations. Molecular geometry of target compound (2-CEB) optimized by using method B3LYP and 6-311G + + (d,p) basis set. Predicted vibrational frequencies were assigned using the VEDA 4 program based on the potential energy distribution (PED). FT-IR spectra, UV–Vis & NMR spectra were all experimentally acquired in the solid phase. The anticipated vibrational frequencies and the optimized geometrical parameters exhibited satisfactory agreement. according to the literature results and the corresponding experimental data. The Natural Bond Order (NBO) study established interaction between donor and acceptor. Molecular Electrostatic Potential (MEP), Electron Localization Function (ELF), Reduced Density Gradient (RDG) and Fukui functions, the reactive sites, and charge distribution of the molecule were highlighted. It also included the energies and diagrams for the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Ease of charge transfer in the compound has been assessed by using the HOMO–LUMO band gap. In the molecular docking study, 2-CEB was docked with 6 different protein receptors.Graphical

Spectroscopic, quantum computational, molecular dynamic simulations, and molecular docking investigation of the biologically important compound-2,6-diaminopyridine

To establish the role in future drug development, 2,6-diamino pyridine (2,6-DAP) was investigated experimentally using computational tools. NMR (1H,13C), FTIR, and UV–Vis spectra were analyzed for the titled compound. The molecular structure was optimized via DFT with the “B3LYP method with 6-311++G(d,p)” The optimized parameters of the structure were assessed with the observed bond characteristics. The vibrational frequencies were studied, PED was carried out, and the calculated vibrational frequency obtained was compared with the experimentally obtained FTIR. NMR (1H,13C) was calculated and compared with the experimentally obtained spectra. UV–vis spectra are calculated in the gaseous phase and different mediums of solvents (methanol, DMSO) by employing the PCM solvent model and TD-DFT method, and the estimated value was compared with experimentally measured data. NBO analysis was done to study the donor-acceptor interaction. The extent of electron charge transfer inside the molecular structure was examined using HOMO–LUMO energy values. The study of excitation analysis led to the creation of E.D.D and H.D.D maps in methanol and DMSO. The AIM and ELF analysis was employed to compute the iso-surface projections, ellipticity, and binding energies. The MEP and Fukui functions evaluate the molecule’s reactive zones. Hirshfeld research was done to analyze interactions among the molecules in the structure of the crystal, and 3D Hirshfeld tops and 2D fingerprint layouts were developed. The molecular docking procedure was used, followed by a 100 ns MD simulation and computation of binding free energy found to delineate the binding affinity of the molecule toward human carbonic anhydrase II (HCA II). Molecular docking studies with several receptor proteins were also conducted to determine the most effective protein-ligand interactions. Biological assessments like drug-likeness also act upon the compound to verify the molecule’s drug-like nature.

Isatin-Fluorene Schiff base as potent antidiabetic agent: Synthesis, DFT calculations, Topology, in silico ADME analysis and molecular docking studies

Diabetes mellitus is a rapidly evolving planetary challenge with substantial societal, salubrity, and financial connotations. Derivatives of isatin with hydrazides, coumarin and aldehydes have proven to possess anti-diabetic activities. Hence, as a novel perspective, isatin was merged with a polycyclic aromatic compound, 2-amino fluorene to build a Schiff base compound with anti-diabetic activity. The anti-diabetic characteristics of the designed compound were scrutinised through in silico molecular docking studies. The designed compound, (Z)-3-((9H-fluoren-2-yl)imino)indolin-2-one (FII) was synthesised in the laboratory using a simple condensation procedure. NMR, HRMS, and Infrared spectral analyses did the experimental structural characterisation of FII. The theoretical investigations of FII were evaluated via density functional theory (DFT). The DFT studies provide insight into the structure, reactivity, and electronic properties of compound FII. The most stable conformation of FII was identified and confirmed by the B3LYP method. The basis set 6-31+G(d) was used for the calculations. The DFT studies include frontier molecular orbital (FMO) analysis to define the global parameters and molecular orbital energy gap, molecular electrostatic potential (MEP) map to find out the reactive sites and natural bond orbital (NBO) analysis for understanding the electron density and charge delocalisation of the title compound, FII. Topological analyses such as ELF, LOL, RDG, and QTAIM were performed to investigate the electronic bonding parameters. Additionally, UV-visible and photoluminescence spectra were performed to investigate the optical properties of FII. The biological potential of the title compound was validated by calculating the physicochemical properties using Lipinski's rule. The molecular docking of the synthesised compound, FII, has been computed using two different proteins, exhibiting inhibitory activity against the α-Glucosidase enzyme. The binding energy and ligand efficiency of both the selected proteins with the ligand molecule were also calculated.

A Computational Analysis of the Proton Affinity and the Hydration of TEMPO and Its Piperidine Analogs.

The study investigated the impact of protonation and hydration on the geometry of nitroxide radicals using B3LYP and M06-2X methods. Results indicated that TEMPO exhibited the highest proton affinity in comparison to TEMPOL and TEMPONE. Two pathways contribute to hydrated protonated molecules. TEMPO shows lower first enthalpies of hydration (ΔH1-M), indicating stronger H-bonding interactions, while TEMPONE shows higher values, indicating weaker interactions with H2O. Solvent effects affect charge distribution by decreasing their atomic charge. Spin density (SD) is primarily concentrated in the NO segment, with minimal water molecule contamination. Protonation increases SD on N-atom, while hydration causes a more pronounced redistribution for water molecules. The stability of the dipolar structure (>N⋅+-O-) is evident in SD redistributions. The frontier molecular orbital (FMO) analysis of TEMPONE reveals a minimum EHOMO-LUMO gap (EH-L), enhancing the piperidine ring's reactivity. TEMPO is the most nucleophilic species, while TEMPONE exhibits strong electrophilicity. Transitioning from NO radicals to protonated forms increases the EH-L gap, indicating protonation stabilizes FMOs. Increased water molecules make the molecule less reactive, while increasing hydration decreases this energy gap, making the molecule more reactive. A smaller EH-L gap indicates the compound becomes softer and more prone to electron density and reactivity changes.

Multi-Step syntheses of different pyrazoline derivatives and in silico studies

In the presented study, a series of methoxylated pyrazoline compounds containing amine (Py1-NH2 and Py2-NH2), tosyl (Py1-Ts and Py2-Ts), and nitrile (Py1-CN and Py2-CN) group were synthesized. The structures of these compounds were clarified through the use of mass spectral, FT-IR, and NMR data. In order to examine the chemical properties of methoxylated pyrazoline derivatives theoretically, calculations were performed on the B3LYP, HF, and M06-2x methods using the 6-31++g(d,p) basis set. In addition, molecular docking calculations were performed to examine the interactions of methoxylated pyrazoline derivatives against cancer proteins. Afterwards, ADME/T was performed to examine the effects of methoxylated pyrazoline derivatives as drugs on human metabolism.

Synthesis, characterization, antiproliferative, antibacterial activity, RDG, ELF, LOL Molecular docking and physico chemical properties of novel benzodiazepine derivatives

Four new benzodiazepine derivatives of 2-(2-(ethyl(methyl)amino)benzo [b][1,4]thiazepin-4-yl)phenol (EMBT), (2-(4-ethylbenzo[b][1,4]thiazepin-2-yl)phenol (EBT), 2-(7-chloro-2-(ethyl(methyl)amino)benzo[b][1,4]thiazepin-4-yl)phenol (CEMBT) and 2-(7-chloro-4-ethylbenzo[b][1,4]thiazepin-2-yl)phenol) (CEBT) has been synthesized. The synthesized compounds were characterized by NMR, FT-IR, UV–Vis and ESI-mass spectrometric techniques. The synthesized compounds were evaluated the cytotoxic assay in vitro antiproliferative activity against MCF-7 and HepG2 cancer cells. Further, antibacterial and antifungal screening were used to investigate the biological profile of 1,4-benzodiazepine derivatives. Antibacterial and antifungal activities were carried out, with potent antifungal activity against a few species. The structural, electronic, and vibrational properties of EMBT, EBT, CEMBT, and CEBT have been examined computationally using the hybrid B3LYP method and the 6–311++G(d,p) basis set basis set. Furthermore, molecular docking was used to study the binding interactions of the synthesized compounds and the standard drug Tamoxifen with the hERalpha LBD target protein.

Empirical, computational studies and non-covalent interactions analysis of a novel salt with cadmium transition metal precursor

In this research paper, (C3H5N2)6[CdCl4][CdCl6] was successfully synthesized using a slow evaporation process. The structure was confirmed through single-crystal X-ray crystallography, FT-IR, and thermal analysis. The material was found to crystallize in the tetragonal system (space group I41/a) and the following parameters a = b = 12.0872 (8) Å; c = 24.6985 (16) Å, the crystal packing shows parallel layers of cations and stacks of discrete anions positioned at y = 1/4 and 3/4. The junction between the monoprotonated imidazolium cations and the anions, along with the crystal structure stability, relies on Cl···H−N, and Cl···H−C hydrogen bonds. Computational investigations, conducted using the B3LYP method with 6–311++G(d,p) and LANL2DZ mixed basis set, demonstrated close alignment between the computed and the experimental data, providing insights into the material's geometrical and vibrational properties. The non-covalent interactions were studied through Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analysis and quantitatively using the Hirshfeld surfaces associated with 2D fingerprint plots. Furthermore, thermal stability was assessed through Thermogravimetric and Differential Scanning Calorimetry (TG–DSC) analysis.

Study of the potential energy surface of reactions in a system containing <i>i</i>-propyl and <i>n</i>-propyl radicals

The energy pathways of possible decomposition and isomerization reactions of iso-propyl (i-C3H7) and n-propyl (n-C3H7) radicals have been studied by computational methods of quantum chemistry. B3LYP, M062X, MP2, and CBS-QB3 methods are used to localize stationary points on the potential energy surface of a system containing propyl radicals. A number of intermediate compounds formed during the isomerization and decomposition of propyl radicals have been identified, and information has been obtained on their structure and thermochemical parameters. Based on the results of the research, a diagram of the energy levels of the system under consideration was constructed.

Exploring the activation potential of heme for 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol

The presence of chlorophenols in water poses a significant threat to human health and the environment. In response to this issue, a study was undertaken to evaluate the catalytic capabilities of chlorinated Heme towards common chlorophenols present in water, such as 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol. The study employed the B3LYP method, a sophisticated computational technique within density functional theory, to investigate the molecular interactions and transformations involved. It scrutinized structural parameters, Wiberg Bond Indices, which offer insights into the strength and nature of chemical bonds, along with spectroscopic data including infrared vibrational spectra, ultraviolet-visible absorption spectra, and molecular fluorescence spectra. Furthermore, the research analyzed molecular binding energies and orbital energy levels before and after the formation of complexes between Heme and the targeted chlorophenols. The findings indicate that Heme displays a notable activation characteristic towards these chlorophenols. This suggests that Heme could act as an effective catalyst in the degradation of chlorophenols in water, presenting a novel approach to water purification. The theoretical insights derived from this study are invaluable, potentially guiding the development of more efficient catalytic systems for treating chlorophenol-contaminated water, thereby reducing the environmental and health risks associated with these hazardous compounds.

In Silico Investigation of Molecular Properties and Molecular Docking of Darunavir: An Anti‐HIV Drug

AbstractA second‐generation HIV protease enzyme inhibitor, darunavir is used in combination therapy for patients with history of prior antiretroviral treatments. It inhibits the cleavage of HIV encoded gag‐pol polyprotein in cells contaminated by a virus and thereby hinders the development of mature and infectious new virions. In this paper, optimization of molecular geometry of darunavir has been obtained by Density Functional Theory based B3LYP and ωB97XD methods with 6–311+G(d,p) basis set. The electro‐optical, global reactivity descriptors, and UV–visible spectrum of the drug have been examined using both the functionals. Further, binding affinity of darunavir at different sites of protein receptor (PDB ID: 5b18) has been analyzed using molecular docking technique. Results have been used to discuss electro‐optical and electronic properties of the drug along with its binding affinities with protein receptors.

Chitosan/La catalyzed synthesis of novel ferrocenated spiropyrrolizidines: Green synthesis, crystallographic, DFT and Hirshfeld surface studies

A novel polymeric catalytic system, utilizing chitosan-bounded lanthanum (chitosan/La), facilitated the formation of spiropyrrolizidine hybrids in higher yield. These hybrids were synthesized via one-pot three component 1,3-dipolar cycloaddition reaction involving ferrocenated chalcones, and azomethine ylides. The chemical structures were elucidated using various spectroscopic techniques and further confirmed via X-ray crystallography of a compound 3. Density functional theory (DFT) calculations executed followed by Gaussian 09 and GaussView 5.0 software provided insights into the optimal structure of molecular compounds. The computational analysis employed the 6–311G++ (d,p) higher-order basis set and the B3LYP method. Additionally, Hirshfeld surface analysis was utilized to predict crystallographic shapes, revealing van der Waals interaction contributing to crystal stabilization.

Mongrel synthesis of tin (IV) based 3-aminopyridine with hydrogen halides: Structural, optical, thermal analysis, DFT, Hirshfeld surface analysis and antibacterial investigations

The novel organic-inorganic hybrid materials (C5H7N4)2 [SnCl6] 2- (1) and (C5H7N4)2 [SnBr6]2-(2) have been synthesized and characterized by single-crystal X-ray diffraction at room temperature. Both compounds demonstrate the crystal system was triclinic with Pī space group. Hirshfeld surface analysis investigate the intermolecular interactions and crystal packing derived by single-crystal XRD data reveals the closer contacts associated with strong interactions. Infrared spectrum of both compounds shows the NH stretching band at 3396 cm−1 which indicates a protonated amine group. The product crystals optical characteristics were inspected using UV–visible and photoluminescence spectroscopy. The thermal characteristics were evaluated simultaneously using thermogravimetric (TG) and differential thermal analysis. Tin formal oxidation state was determined as +4 through bond valence sum calculations and CSM shows the ideal octahedral geometry of the anions. DFT calculations utilizing the B3LYP method with the LanL2DZ basis set provide optimized geometries and molecular electrostatic potential maps. We explored the energy difference between (HOMO) and (LUMO) orbitals to understand molecular electrical transport capabilities. The biological activity of the investigated compounds are examined against pathogens which indicates efficacy against bacterial strains.

In silico modelling of radiative efficiencies of anthropogenic greenhouse gases

Radiative efficiency (RE) is a climate metric adopted in international reports on climate change to quantify the greenhouse capacity of gases, and hence to guide decision-making processes and drive transitions in the production and utilization of chemicals in different application fields. Key quantities for the determination of the RE of a gas are the atmospheric irradiance profile and the infrared (IR) absorption cross section spectrum. The latter is usually measured experimentally, even though acquiring high-quality IR spectra can pose severe challenges, sometimes limiting the accuracy or the accessible spectral range. While computational quantum chemistry methods have emerged as valuable tools to simulate IR absorption properties, their application to REs estimation is still limited to the use of the double-harmonic approximation, which presents fundamental limitations. In this work, a cost-effective quantum chemical (QC) workflow including non-empirical anharmonic contributions to spectral properties and an automatic identification of conformer distribution is presented for the accurate evaluation of REs using a range of atmospheric irradiance profiles. Different levels of theory are considered, according to the current state-of-the-art, and the accuracy of the QC RE tool is demonstrated with reference to a number of representative halocarbons widely used in refrigeration, manufacturing, and pharmaceutical fields. The results show that REs can be computed with an average accuracy of 5% using double-hybrid functionals, which overshoot the widely used B3LYP method. Finally, the QC methodology is applied to determine the REs of selected halocarbons for which data is limited, or to address some contradictory results appeared in the literature for some species. The outcomes of this work demonstrate that QC anharmonic IR cross section spectra can be used to estimate REs with an accuracy on par with that of experimental measurements, hence applicable to challenging cases for providing data for policymakers as well for screening purposes when seeking new replacement compounds.

Hyperhardness and hypersoftness of atoms and their ions

ContextThe theory of reactivity based on cDFT has been supplemented with the new method of calculating the atomic and local indices. With the use of previously derived relationship of the electron density gradient to the softness kernel and to the linear response function, we deliver theoretical analysis to obtain significant reactivity indices—the electron density derivatives: local softness and local hypersoftness together with the global hyperhardness index and the derivative of the global softness with respect to the number of electrons. The local derivatives have been applied in the calculation of responses of atoms to perturbation by an external potential by the alchemical approach. The vital role of the local softness has been confirmed; the potential role of the hypersoftness has been indicated.MethodOur original theoretical scheme has been numerically illustrated with the results obtained with electron density calculations with B3LYP method implemented in Gaussian 16 package. The aug-cc-pvqz basis set has been routinely applied, except for the Ca atom (cc-pvqz). Using the pVTZ basis set recommended by Sadlej was necessary for the potassium atom.Graphical

Experimental, quantum chemical spectroscopic investigation, topological, molecular docking/dynamics and biological assessment studies of 2,6-Dihydroxy-4-methyl quinoline

The present work is a comprehensive investigation of the spectral, electronic structure, bonding, and reactivity of the 2,6-dihydroxy-4-methylquinoline (26DH4MQ) molecule through a wide range of experimental and quantum chemical spectroscopic calculations techniques, along with its applications as nonlinear optical materials and biological assessments. The study utilized density functional theory (DFT) and time-dependent density functional theory (TD-DFT) with the B3LYP method and the 6-311G++(d,p) basis set to analyze the structural and molecular properties of 26DH4MQ. The findings from UV–Vis, FT-IR, and FT-NMR spectroscopy show a strong agreement between the experimentally obtained vibrational frequencies and chemical shifts and those predicted by computational methods. Local reactivity descriptors, such as the dual descriptor, Fukui functions, and the molecular electrostatic potential (MEP) map, were used to identify the reactive regions of the molecule. Additionally, natural bond orbital (NBO) analysis provided insights into the charge transfer characteristics of 26DH4MQ, which helps to stabilize the molecular system. The study also revealed notable nonlinear optical (NLO) properties, with polarizability (18.52 × 10–24e.s.u.) and first-order hyperpolarizability (2.26 × 10–30e.s.u.) values that surpass those of standard organic compounds, suggesting significant potential for optoelectronic applications. The biological evaluation of 26DH4MQ assessed its drug-likeness, toxicity, enzyme inhibition, and ADME (Absorption, Distribution, Metabolism, and Excretion) parameters, highlighting its pharmaceutical potential. Furthermore, molecular docking and dynamics studies illustrated the compound's interaction with proteins, indicating its potential role as an insulin inhibitor.

An electrochemical and theoretical approach towards the efficient microwave synthesis of imidazolium-based ionic liquids for unprecedented mild steel corrosion inhibition in 0.5 M H2SO4 solution

The inhibition potential of newly synthesized imidazolium-based ionic liquids (IL-1 and IL-2) on mild steel corrosion in a 0.5 M H2SO4 solution has been comprehensively investigated using gravimetric analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy across various temperatures. Gravimetric analysis indicated that the adsorption of these inhibitors adhered to the Langmuir adsorption isotherm. Significantly, IL-2, featuring a longer alkyl chain, demonstrated superior inhibition efficiency (92.51 % at 303 K) compared to IL-1 (88.71 % at 303 K). Potentiodynamic polarization studies revealed a mixed-type inhibitory behavior, impacting both anodic and cathodic reactions. Surface morphological analyses via SEM and EDX confirmed the formation of a protective film on the mild steel surfaces, substantiating the corrosion inhibition capabilities of IL-1 and IL-2. The novelty of this research lies in the application of density functional theory (DFT) using the B3LYP method, which elucidated that the alkyl chain length at the N-3 position in imidazolium cation-based ionic liquids significantly enhances their inhibition potential. This mechanistic insight suggests that these ionic liquids effectively obstruct both anodic and cathodic sites, providing robust corrosion protection in a 0.5 M H2SO4 solution.

Synthesis, Antimicrobial, DNA Interactions, In Vitro Cytotoxicity, and Cell Cycle Analysis Efficiency of Newly Nano‐Sized Cu (II), Ni (II), Co (II), and Zn (II) Thio‐Schiff Base Complexes of 2‐((E)‐((4,5‐Dimethyl‐2‐(((E)‐4‐Methylbenzylidene)Amino)Phenyl)imino)Methyl)‐Benzenethiol

ABSTRACTNano‐sized bivalent metal complexes, specifically [M(L)2] with L = 2‐((E)‐((4,5‐dimethyl‐2‐(((E)‐4‐methylbenzylidene)amino)phenyl)‐imino)methyl)benzenethiol] (C23H22N2S) and M = Cu (II) (C1), Co (II) (C2), Ni (II) (C3), and Zn (II) (C4), underwent synthesis and subsequent characterization. Elemental analyses, infrared, NMR, mass, electronic, magnetic susceptibility, conductivity assessments, and X‐ray diffraction studies were used to assess our bivalent metal complexes. DFT studies were used to study the tautomeric equilibrium of the tridentate thio‐Schiff base ligand (HL), via the DFT\B3LYP method in connection with a 6–311G* correlation consistent basis set. Two tautomers, which are thione and thiol forms, were studied to estimate the predominant one. The metal formed four coordinated with the tridentate N2S donor thio‐Schiff base to form octahedral geometry complexes. The SEM, TEM, XRD, AFM, and EDX of the studied complexes unveiled distinct and strong diffraction peaks, signifying their crystalline nature and providing evidence of their particle sizes being within the nano‐size. The crystal sizes calculated for all complexes were determined to be ranging from 27.73 to 76.39 nm. The interactions between metal complexes and calf thymus DNA, and their potential for mimicking insulin activity, were investigated in a controlled lab setting by measuring their ability to inhibit alpha‐amylase. The antimicrobial potential of thio‐Schiff base ligand (HL) plus complexes (C1–C4) were tested. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT‐DNA) interaction with the nano‐sized metal (II) chelates. Our flow cytometry data indicate significant levels of apoptosis and cell cycle arresting in both liver and breast cancer cell lines.

Rational Design of Cyclopentadiene-Based Super- and Hyperacids Based on Aromaticity.

The design and synthesis of neutral organic superacids have been of interest recently due to their vast applications in chemistry and material sciences, for example, olefinic polymerization, isolation of highly reactive short-lived cations, etc. Cyclopentadiene behaves as a mild organic acid, producing a stable conjugate base by gaining aromaticity and conjugation after deprotonation. To stabilize conjugate bases of organic acids to show superacidities and hyperacidities, we considered aromatic phenyl substituents with cyclopentadiene (mono-, di-, and triphenyl-substituted cyclopentadiene and their cyano derivatives). The MP2, DFT (B3LYP, M06-2X), and CBS-QB3 methods were used to calculate the gas-phase proton affinities of the parent cyclopentadiene, and the DFT methods were chosen for the substituted cyclopentadiene as they yield an experimental proton affinity of cyclopentadiene of 253.66 kcal/mol (Expt. 253.6 ± 1.3 kcal/mol). The stable trisubstituted cyclopentadiene derivative shows gas-phase enthalpies of deprotonation (ΔHacid) of 245 and 239 kcal/mol with DFT B3LYP and M06-2X methods, respectively, with values in the range of hyperacidity. Some of the tautomers of cyclopentadiene derivatives show hyperacidity, with proton affinity values of 205-240 kcal/mol. Triphenyl-substituted cyclopentadiene behaves as a moderate acid but transforms into a superacid after replacing the phenyl group with nitrobenzene, which is a stronger acid than H2SO4 (ΔHacid = 298 kcal/mol). The nucleus-independent chemical shift (NICS) shows the extent of conjugation in the derivatives of cyclopentadienyl anions after deprotonation, which affects the stabilities of conjugate bases, i.e., the acidities of the protonated species. The calculated harmonic oscillator model of aromaticity and NICS indices reveal that the stability of conjugate bases as well as their acidities increase with increasing aromaticity of cyclopentadiene rings after deprotonation in all molecules.

Synthesis, spectral, DFT and anticancer studies on bis(N-(3-methoxybenzyl)-N-(pyridin-3-ylmethyl)dithiocarbamato-S,S’)M(II) (M= Pd, Pt)

We reported synthesis of bis(N-(3-methoxybenzyl)-N-(pyridin-3-ylmethyl)dithiocarbamato-S,S’)M(II) (where M(II) = palladium(II) (1), platinum(II) (2)). Both the complexes were characterized by elemental analysis, FTIR, UV–visible, 1H and 13C NMR spectroscopy. Based on FTIR spectral studies, bidentate coordination of dithiocarbamate ligand was proposed for both complexes. UV–visible spectral data confirm the formation of square planar complexes. The structure properties, frontier molecular orbital (FMO), molecular electrostatic potential (MEP), chemical reactivities and Mulliken charges were investigated using density functional theory (DFT)/B3LYP methods with 6-31+G (d, p) basis sets and LanL2DZ for light atoms and heavy atoms, respectively. FMO and Mulliken charges recognize the chemical active sites of 1 and 2 responsible for its chemical activity. In vitro anticancer activity of complexes 1 and 2 were analyzed on MCF-7 by MTT assay method. Results show that platinum complex 2 has higher activity compared to these of palladium complex 1.