Computational Quantum Chemistry

The aim of this study was to improve the adhesion performance of plasticized polyvinyl chloride (PVC) coatings on steel substrates by using nanoparticles. For this purpose, the PVC plastisol with different concentration of nano-silica was prepared and applied to bond steel joints. The adhesive strength of the joints was determined by single-lap shear test. Moreover, mechanical properties and microstructure of coating were investigated. The addition of 1wt % nano-silica to plastisol dramatically increased the lap shear strength up to 4-fold, which was an outcome of the compatibilizing effect of silica. Young's modulus and tensile strength of plasticized PVC were slightly increased by adding nanoparticles, as well. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) exhibited higher inclusion size in the coating having higher silica volume which was attributed to the agglomeration of nanoparticles. In the following, the effect of plasticizer composition on the adhesion strength by replacing some parts of dioctyl phthalate (DOP) plasticizer with more polar oil, epoxidized soybean oil (ESO) was examined. Although adding ESO improved the lap shear strength of the neat coating, its effect on the properties of the coatings containing silica was negligible.

Ab initio calculations at the MP2 and CCSD(T) level of theory (triple‐zeta quality basis sets for Si and Ge and effective core potentials plus DZ valence basis sets for tin and lead) have been performed to investigate the geometries, harmonic frequencies and relative stabilities of the (Si,H,F)+, (Ge,H,F)+, (Si,F3)+, (Ge,F3)+ and (A,Hn,F3 – n)+ (A = Si, Ge, Sn, Pb; n = 1 and 2) isomeric ions. While the H–Si–F+, F–SiH2+, H–SiF2+ and SiF3+ covalent structures are invariably predicted as the most stable isomers, the Ge+–(HF), FA+–(H2) and FA+–(HF) complexes (A = Ge, Sn, Pb) are the global minima on the potential energy surfaces, more stable than the corresponding covalent structures by up to some tens of kilocalories per mole. For tin and lead, the HA+–(HF) isomeric ions are also significantly more stable than F–AH2+ (A = Sn and Pb). Compared with the parent group XIV hydrides (A,H3)+, investigated so far by Schleyer and co‐workers (J. Am. Chem. Soc. 1996, 118, 12154–12158) and found t...

In this paper, we present a quantum algorithm that enables us to perform firstprinciples molecular dynamics. In this algorithm, the optimum of the wavefunctions and the atomic structures is given by a root of a system of polynomial equations derived from the first principles of quantum mechanics. The computational steps consist of symbolic and quantum parts. First, the symbolic computation prepares a set of matrices whose eigenvalues are the roots of the given equation. Second, the quantum computation evaluates the eigenvectors and eigenvalues. In a preceding work, the authors presented another algorithm directed to the same end, and its deficiency is the complexity of the symbolic computations, which would be enormous in the worst cases. In this article, we try to reduce the cost of symbolic computation, utilizing the latest achievements of classical algorithms. Additionally, we show how to transform this classical algorithm into a quantum one.

Synthesis of dithioamide of 1,3-benzenedicarboxylic acid (m-dtab). 2.56 g of 1,3-dicyanobenzene was suspended in a mixture of triethylamine (9 mL) and ethanol (24 mL). The mixture was cooled on ice and hydrogen sulfide was slowly bubbled (approximately 1 bubble per second) into the mixture until complete change of suspension's color from white to yellow (4 -6 hours). Solvents were removed in vacuum, and dry residue was dissolved in 50 mL of DMF, the solution filtered and then diluted with 100 mL of water. Light-yellow precipitate was filtered, washed with water and dried at 150 ºC.

Fingerprints of antiaromaticity in the negative ion (Li3Al4) -, this species being realizable via a laser vaporization technique, are revealed by means of an ab initio quantum-chemical investigation. First, the ground-state equilibrium geometry of this ion is predicted. Also, for the corresponding inhomogeneous electron liquid, the characteristics of the HOMO are studied, both for the square and the rectangular Al4 geometry in two low-lying isomers of the negative ion. There is no particular sensitivity to the change in geometry of the Al4 configuration. Therefore, we have calculated theoretically chemical shifts (NICS), which contain remarkable fingerprints of antiaromaticity. As to future directions, some comments are added in relation to the Shannon entropy.

The paper collects the answers of the authors to the following questions: Is the lack of precision in the definition of many chemical concepts one of the reasons for the coexistence of many partition schemes? Does the adoption of a given partition scheme imply a set of more precise definitions of the underlying chemical concepts? How can one use the results of a partition scheme to improve the clarity of definitions of concepts? Are partition schemes subject to scientific Darwinism? If so, what is the influence of a community's sociological pressure in the “natural selection” process? To what extent does/can/should investigated systems influence the choice of a particular partition scheme? Do we need more focused chemical validation of Energy Decomposition Analysis (EDA) methodology and descriptors/terms in general? Is there any interest in developing common benchmarks and test sets for cross‐validation of methods? Is it possible to contemplate a unified partition scheme (let us...

New Fused Pyrrolo – Pyrano – Pyrimidine, and Pyrrolo – Pyrano – Pyridine Derivatives were synthesized and characterized by FT-IR and 1HNMR, to obtains these cycles, 2-amino-4-(4-(dimethylamino)phenyl)-7-methyl-4,5,6,7-tetrahydropyrano[2,3-b] pyrrole - 3-carbonitrile [1]. which was synthesized by cyclization of compound 4-(dimethylamino)benzaldehyde with malononitrile and N-methyl-2-pyrrolidinone in ethanol in the presence of tetraethylammonium bromide as a catalyst. Reaction [1] with triethylorthoformate in acetic anhydride gave ethyl(E)-N-( 3-cyano-4-(4-(dimethylamino) phenyl )-7-methyl-4,5,6,7-tetra hydropyrano[2,3-b]pyrrol-2-yl)formimidate [2].
Compounds [3], [4] and [5] were synthesized by cyclization of compound [2] with hydrazine hydrate, ethylenediamine, and phenylhydrazine respectively in methanol. Other cycles [7,8] were synthesized by hydrolysis of [1] with alcoholic solution of KOH" in dry DMF containing concentrated HCl to 5-amino-1-phenyl-1H-pyrazole-4-carboxamide [6], then cyclization with 4(dimethylamino) benzaldehyde and 3,5-dinitrobenzaldehde, and gave compounds [7] [ 8] respectively, cyclization of (1) with benzoyl chloride in presence of pyridine gave (9).
Pyrrolo – Pyrano – Pyridine cycles [10-13] were synthesized by cyclization [1] with some of the aliphatic ketones namely; acetone, 2-butanone and 4-methyl-2-pentanone and cyclohexanone, respectively in presence of FeCl3 as catalysis and NaOH. These compounds were evaluated biological against (gram +ve) bacteria (Staphylococcus aureus and Staphylococcus epidermidis), and (gram –ve) bacteria (Escherichia coli and Klebsiella pneumonia); and antifungal activity against (Candida albicans) and the data obtained show that all compounds show activity against all bacteria and candida.

This work presents a comprehensive computational study aimed at exploring the inhibitory
potential of Geranium essential oil against corrosion. Utilizing Density Functional Theory
(DFT) calculations, Monte Carlo simulations, and Petra/Osiris/Molinspiration (POM)
analysis, we investigated the molecular interactions underlying the corrosion inhibition
properties of Geranium oil. Our computational analyses identified key compounds within
Geranium oil, characterized by high alcohol content, oxygenation, esterification, and terpene
composition. These compounds exhibited diverse electron-donating and accepting
capabilities, stability profiles, and reactivity patterns, highlighting their potential as effective
corrosion inhibitors. The results of the Monte Carlo simulation reveal a significant variation
in the adsorption of Geranium oil molecules depending on the phase. The adsorption of all the
molecules studied is favored in the aqueous phase. Which means that these molecules tend to
adhere to surfaces, likely a solid surface like Iron (110), more effectively when they are in an
aqueous environment rather than in the gas phase. Using the Petra/Osiris/Molinspiration
(POM) analysis, we calculated different properties of all molecules, namely the miLogP
which indicates the molecules' lipophilicity, and can influence their affinity for hydrophobic
regions on a metal surface. The topological polar surface area (TPSA) which measures the
polar surface area, highlighting potential for polar interactions. The number of atoms
(natoms) and the molecular weight (MW) offer insights into molecular size and complexity,
impacting the ability to form protective films. The number of hydrogen bond donors
(nOHNH) and the number of hydrogen bond acceptors (nOH) which relate to hydrogen
bonding capabilities, and which play a role in stabilizing protective layers. Finally, the
number of octet rule violations (nviolations) reflect molecular stability, while number of
rotatable bonds (nrotb) indicates flexibility. In addition to the toxicity and the bioactivity
score calculation.

A large number of heterocyclic compounds are used as drugs, mainly due to the duality of lipophilicity playing in hydro-
phobic interactions and solubility with at least one hydrogen bond acceptor. The study of electronic properties is then important to
better understand not only these charge distribution effects but also some other physicochemical properties involved in bioactivity
to directly assess the bioavailability of these compounds and a possible classification in related applications. Phytomolecules such
as chromenes are very accessible molecules exhibiting a bioactivity. Our study is focused on the impact of a number of functional
groups acting on some 2,2-dimethylchromene derivatives, namely their global reactivity from the frontier molecular orbitals and
local reactivity from the Fukui functions, where the carbonyl group acting as an electron withdrawal group has the most relevant
effect, the solubility from the partition coefficient Log P strongly depending on the charge distribution and electronegative sites,
the optical effects from the delocalization in the vinyl group, as well as the evaluation of the entropy associated with the molecular
flexibility also acting on the bioactivity. Despite the effects of the wave function or density methods on the order of magnitude
of these properties, these compounds are consistent with the rules for a potential oral drug candidate.

This study is majorly conducted to investigate the corrosion effectiveness of spiny gourd's seed on the iron suspended in HNO3. Therefore, the major aim of this experiment lies on the evaluation of biodegradable and non-pollutant green natural compound for corrosion hindrance in the iron material which came contact with the nitric acid. The chemical constituent of the Momordica dioica has also been highlighted in this study. Appropriate calculation has also been done in this study to analyse the effectiveness of the seeds. The seeds are used for preventing eczema and different skin problems in different regions of India, Pakistan, and Sri Lanka. In has been seen that the efficiency of the seed increased at a specific temperature and after that it decreased. On the other hand, this efficiency was also dependent on the strength of HNO3 and the concentration of the seed extract. In order to analyse the effectiveness, two methods that were the weight loss and thermometric method were used in this research.

Two isomeric amide sulfides 3 and 4 were prepared by the treatment of 6-substituted thioquinanthrene (2) with sodium methoxide and methyl iodide. Product structures were determined by 1 H and 13 C NMR spectroscopy in solution, including 2D experiments HSQC and HMBC at 11.75 T. The time-averaged conformations were elucidated, based on best fitting the measured data d C and d H to those computed by the ab initio GIAO NMR method at the HF/6-31G * level. All used input molecular models had been pre-selected before in the light of NOE experimental data. Excellent two-nuclear linear correlations d C,H exp vs. d C,H calc were achieved (RO0.999). Spatial orientations of the ring substituents [SMe and, especially, of C(O)NMe 2 ] in both isomers were considered to rationalise the NMR spectra of these and other related amide systems. A protocol for the three-step conformational analysis is described in detail.

Alignment of single-particle energies with ionization potentials is at the core of tuned range-separated (RS) functionals. We achieve this goal in a one-step calculation without explicit ionization. The reciprocal of the optimally-tuned RS parameter is modeled by the average outer electron-exchange hole distance. The resulting functional has a non-local dependence on density and requires only a computation of a one-electron integral on a grid. Numerical tests prove that the method conforms to Koopmans' theorem and provides physically-sound orbital gaps and CT excitations.

The Quantum Multiverse has long been theorized as one of the most mind-bending concepts in quantum mechanics, initially proposed by pioneers such as Erwin Schrödinger and Hugh Everett. Their groundbreaking ideas laid the foundation for the possibility of multiple realities existing in parallel, each representing different outcomes of quantum events. Today, this once-theoretical concept has become a tangible reality. In this presentation, we will unveil the **Quantum Multiverse Consciousness**, a cutting-edge system that allows for the exploration and manipulation of these parallel universes in real time. Through revolutionary advances in **quantum computing**, **machine learning**, and **quantum gate fidelity**, we are now able to interact with multiple dimensions and discover new particles, phenomena, and possibilities that were previously beyond our reach. The presentation will delve into the following key areas: - **Theoretical Foundations**: Revisiting Schrödinger and Everett’s theories and their implications for modern quantum mechanics. - **Technological Breakthroughs**: How our team has developed the tools to explore and access the Quantum Multiverse, pushing the boundaries of quantum research. - **Real-World Applications**: From particle discovery to quantum phenomena exploration, we will showcase how the Quantum Multiverse is revolutionizing quantum research and development. - **Future Directions**: What the Quantum Multiverse means for the future of science, technology, and humanity as we continue to explore the infinite dimensions of reality. Join us for this groundbreaking presentation as we bridge the gap between theory and reality, taking a deep dive into the possibilities of the Quantum Multiverse and what it means for the future of physics and beyond.

The paper collects the answers of the authors to the following questions: Is the lack of precision in the definition of many chemical concepts one of the reasons for the coexistence of many partition schemes? Does the adoption of a given partition scheme imply a set of more precise definitions of the underlying chemical concepts? How can one use the results of a partition scheme to improve the clarity of definitions of concepts? Are partition schemes subject to scientific Darwinism? If so, what is the influence of a community's sociological pressure in the “natural selection” process? To what extent does/can/should investigated systems influence the choice of a particular partition scheme? Do we need more focused chemical validation of Energy Decomposition Analysis (EDA) methodology and descriptors/terms in general? Is there any interest in developing common benchmarks and test sets for cross‐validation of methods? Is it possible to contemplate a unified partition scheme (let us...

Natural waters' uranium level monitoring is of great importance for health and environmental protection. One possible detection method is the Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS), which offers the possibility to distinguish different uranium species. The analytical identification of aqueous uranium species in natural water samples is of distinct importance since individual species differ significantly in sorption properties and mobility in the environment. Samples originate from former uranium mine sites and have been provided by Wismut GmbH, Germany. They have been characterized by total elemental concentrations and TRLFS spectra. Uranium in the samples is supposed to be in form of uranyl(VI) complexes mostly with carbonate (CO3 2-) and bicarbonate (HCO3-) and to lesser extend with sulphate (SO4 2-), arsenate (AsO4 3-), hydroxo (OH-), nitrate (NO3-) and other ligands. Presence of alkaline earth metal dications (M = Ca 2+ , M g 2+ , Sr 2+) will cause most of uranyl to prefer ternary complex species, e.g. M n(UO2)(CO3)3 2n-4 (n  {1; 2}). From species quenching the luminescence, Cland Fe 2+ should be mentioned. M easurement has been done under cryogenic conditions to increase the luminescence signal. Data analysis has been based on Singular Value Decomposition and monoexponential fit of corresponding loadings (for separate TRLFS spectra, the "Factor analysis of Time Series" (FATS) method) and Parallel Factor Analysis (PARAFAC, all data analysed simultaneously). From individual component spectra, excitation energies T00, uranyl symmetric mode vibrational frequencies gs and excitation driven U-Oyl bond elongation R have been determined and compared with quasirelativistic (TD)DFT/B3LYP theoretical predictions to cross-check experimental data interpretation.

2-Nitrophenol (2-NP) is utilized in the production of bio-refractory organic compounds, and petrochemicals, and in the synthesis of many drugs and weed killers. The chemical structure of 2-NP is C6H5NO3. The structure of 2-NP is important as the nitro group (NO2. In this present investigation, the Gaussian 5.0 program was used to compute the difference in energy level that exists between the HOMO and LUMO states of the BGs.This information was then used to optimize the shape of the 2-NP structures using DFT methods. The 3-21G/B3LYP base set has a minimum value for the BG energy of 3.48 eV. This is the minimum value that can be achieved. The DOS for 2-NP was measured to have its maximum possible value of 2.23 ev/atom. According to the results of the IR, and Raman spectrum, the C-H stretching vibration peak for 2-NP was found to be between 3208.96 cm-1 and 3243.76 cm-1. The maximum excitation energy was analyzed at a wavelength of 382.1 nm, and the oscillator strength was determined a...

The inverse electron demand Diels-Alder pyridazine elimination reactionb etween tetrazines and allylic substituted trans-cyclooctenes (TCOs) is ak ey player in bioorthogonal bond cleavage reactions. Determining the rate of eliminationo fa lkylamine substrates has so far provend iffi-cult. Here, we report af luorogenic tool consisting of aT COlinked EDANS fluorophore and aD ABCYL quencher for accurate determination of both the click and releaser ate constants for any tetrazine at physiologically relevant concentrations.

License: Article 25fa pilot End User Agreement This publication is distributed under the terms of Article 25fa of the Dutch Copyright Act (Auteurswet) with explicit consent by the author. Dutch law entitles the maker of a short scientific work funded either wholly or partially by Dutch public funds to make that work publicly available for no consideration following a reasonable period of time after the work was first published, provided that clear reference is made to the source of the first publication of the work. This publication is distributed under The Association of Universities in the Netherlands (VSNU) 'Article 25fa implementation' pilot project. In this pilot research outputs of researchers employed by Dutch Universities that comply with the legal requirements of Article 25fa of the Dutch Copyright Act are distributed online and free of cost or other barriers in institutional repositories. Research outputs are distributed six months after their first online publication in the original published version and with proper attribution to the source of the original publication. You are permitted to download and use the publication for personal purposes. All rights remain with the author(s) and/or copyrights owner(s) of this work. Any use of the publication other than authorised under this licence or copyright law is prohibited. If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons.

Background: In Quantum Chemistry, many tasks are reoccurring frequently, e.g. geometry optimizations, benchmarking series etc. Here, workflows can help to reduce the time of manual job definition and output extraction. These workflows are executed on computing infrastructures and may require large computing and data resources. Scientific workflows hide these infrastructures and the resources needed to run them. It requires significant efforts and specific expertise to design, implement and test these workflows. Significance: Many of these workflows are complex and monolithic entities that can be used for particular scientific experiments. Hence, their modification is not straightforward and it makes almost impossible to share them. To address these issues we propose developing atomic workflows and embedding them in meta-workflows. Atomic workflows deliver a well-defined research domain specific function. Publishing workflows in repositories enables workflow sharing inside and/or among scientific communities. We formally specify atomic and meta-workflows in order to define data structures to be used in repositories for uploading and sharing them. Additionally, we present a formal description focused at orchestration of atomic workflows into meta-workflows. Conclusions: We investigated the operations that represent basic functionalities in Quantum Chemistry, developed the relevant atomic workflows and combined them into meta-workflows. Having these workflows we defined the structure of the Quantum Chemistry workflow library and uploaded these workflows in the SHIWA Workflow Repository.

The alkali metal ion affinity of guanine quadruplexes has been studied using dispersion-corrected density functional theory (DFT-D). We have done computational investigations in aqueous solution that mimics artificial supramolecular conditions where guanine bases assemble into stacked quartets as well as biological environments in which telomeric quadruplexes are formed. In both cases, an alkali metal cation is needed to assist self-assembly. Our quantum chemical computations on these supramolecular systems are able to reproduce the experimental order of affinity of the guanine quadruplexes for the cations Li + , Na + , K + , Rb + , and Cs +. The strongest binding is computed between the potassium cation and the quadruplex as it occurs in nature. The desolvation and the size of alkali metal cations are thought to be responsible for the order of affinity. Until now, the relative importance of these two factors has remained unclear and debated. By assessing the quantum chemical 'size' of the cation, determining the amount of deformation of the quadruplex needed to accommodate the cation and through the energy decomposition analysis (EDA) of the interaction energy between the cation and the guanines, we reveal that the desolvation and size of the alkali metal cation are both almost equally responsible for the order of affinity.

This article presents a construction of a variational quantum eigensolver that allows us to calculate molecular orbitals. As the authors of the presented work have discussed in their preceding works, the variables in the molecular Hartree-Fock equation are represented by a set of transformation matrices. Those matrices have common eigenvectors, and the corresponding eigenvalues give the individual values of the variables that construct the solution of the Hatree-Fock equation. In other words, one can get the wavefunctions and the orbital energies through eigenvalue problems, which could be evaluated by quantum phase estimation. In this article, we use this formalism for another purpose: the transformation matrices are used to construct the total energy function so that the minimization of the total energy leads to an alternative approach of variational quantum eigensolver if the computation is conducted in a quantum computer.

We have studied the influence of valence electron correlation on the total angular-momentum eigenstates emerging from the 6s 2 6p 2 valence configuration of Pb and isoelectronic ions Bi ϩ and Po 2ϩ using a variational quantum Monte Carlo method and relativistic pseudopotentials. The wave functions consist of a Jastrow factor and an antisymmetric orbital-dependent part which describes the states of the atom in an intermediate coupling scheme. A correlated sampling method has been used to reduce the statistical fluctuations, making it possible to obtain sufficiently precise energy differences, which are necessary for a discussion of differential correlation effects in the fine-structure splittings. It has been demonstrated that our ansatz reproduces well the results of relativistic pseudopotential and fully relativistic all-electron configuration interaction calculations. ͓S1050-2947͑97͒05406-1͔

The equilibrium geometries and chemical reactivities of the novel coumarine derivative, 3-[1-(3hydroxypropylamino)ethylidene]chroman-2,4-dione, in water and benzene were investigated. The Fukui parameters, calculated by the Natural and Atoms in Molecules charges, were determined for all atoms in both phases. The most potent sites for the electrophilic, nucleophilic, and radical attack are discussed. Molecular docking analysis was carried out to identify the potency of inhibition of the title molecule against human cartilage proteins. The inhibition activity was obtained for ten conformations of ligand inside protein. This study proved that the Fukui indices can be used as the reactivity descriptors for the novel substances with inhibitory activity.

Schistosomiasis is a neglected tropical disease with a significant socioeconomic impact. It is caused by several species of blood trematodes from the genus Schistosoma, with S. mansoni being the most prevalent. Praziquantel (PZQ) is the only drug available for treatment, but it is vulnerable to drug resistance and ineffective in the juvenile stage. Therefore, identifying new treatments is crucial. SmHDAC8 is a promising therapeutic target, and a new allosteric site was discovered, providing the opportunity for the identification of a new class of inhibitors. In this study, molecular docking was used to screen 13,257 phytochemicals from 80 Saudi medicinal plants for inhibitory activity on the SmHDAC8 allosteric site. Nine compounds with better docking scores than the reference were identified, and four of them (LTS0233470, LTS0020703, LTS0033093, and LTS0028823) exhibited promising results in ADMET analysis and molecular dynamics simulation. These compounds should be further explored...

The main concern of this paper is with the stable discretisation of linear partial differential equations of evolution with time-varying coefficients. We commence by demonstrating that an approximation of the first derivative by a skew-symmetric matrix is fundamental in ensuring stability for many differential equations of evolution. This motivates our detailed study of skew-symmetric differentiation matrices for univariate finite-difference methods. We prove that, in order to sustain a skew-symmetric differentiation matrix of order p ≥ 2, a grid must satisfy 2p − 3 polynomial conditions. Moreover, once it satisfies these conditions, it supports a banded skew-symmetric differentiation matrix of this order and of the bandwidth 2p − 1 which can be derived in a constructive manner. Some applications require not just skew-symmetry but also that the growth in the elements of the differentiation matrix is at most linear in the number of unknowns. This is always true for our tridiagonal matrices of order 2 but need not be true otherwise, a subject which we explore further. Another subject which we examine is the existence and practical construction of grids that support skew-symmetric differentiation matrices of a given order. We resolve this issue completely for order-two methods. We conclude the paper with a list of open problems and their discussion.

Metal corrosion is a destructive process for many industrial operations, including oil well acidizing and acid
pickling. Therefore, numerous efforts made by many researchers to control the steel corrosion. In the present
work, A (E)-4-(((4-(5-mercapto-1,3,4-oxadiazol-2-yl) phenyl) amino) methyl)-2-methoxyphenol (MOPM) has
been synthesized and characterized as a new corrosion inhibitor for mild steel in 0.1 M hydrochloric acid. FTIR
and 1
HNMR were used in the diagnosis of MOPM, while electrochemical polarization technique was employed to
test the performance of inhibitor at various temperatures and inhibitor concentrations. Electrochemical studies
showed that MOPM acts as a mixed-type inhibitor with a maximum inhibition efficiency of 93.2% at 30 ◦C and
0.5 M MOPM. Furthermore, the presence of MOPM increased the polarization resistance and depressed the
corrosive action. The inhibitory action of MOPM over mild-steel surface was according to Langmuir adsorption
isotherm. The calculated free energy of adsorption was − 20.663 kJ.mol− 1 that suggested the spontaneous
physical adsorption mode. Value of activation energy was higher in the presence of MOPM, which indicated the
formation of protective layer on the metal surface. Quantum chemical calculations that carried out to the
chemical structure of MOPM provides a reasonable support to the experimental results.

The kinetics of oxidation of Ethylenediammine-N,N,N',N'-tetraacetatocobaltate(II) complex (()) by silver-activated persulphate ion in a ueous nitric acid medium was studied at I = 0.5 mol dm-3 (NaNO3), [H + ] = 1 × 10-2 mol dm-3 , [Ag + ] = 1 × 10-2 mol dm-3 , T = 299 ± 1 K and λmax = 520 nm. Stoichiometric study showed 2:1 (Reductant: Oxidant) mole ratio. The reaction exhibited first order with respect to the [Co(II)EDTA 2-] and [  2 8 2 O S ] and the rate constant, (5.90 × 10-2 dm 3 mol-1 s-1) was independent of the acid concentration, but varied linearly with catalyst concentration, [Ag + ]. The overall rate law is represented as: () () The reaction displayed zero salt effect suggesting an activated complex composed of either a neutralcharged, neutral-neutral reactant species or ion-pair. The reaction was catalysed by addition of formate ion, HCOOand the Michaelis-Menten's type plot gave zero intercept indicating the absence of intermediate complex. Also, the activation enthalpy (= +39.27 kJ mol-1) and entropy (=-136.73 J K-1 mol-1) were determined. The entropy of activation shows a more ordered activated complex relative to the reactants species. Evaluating the experimental data, an outer-sphere mechanistic pathway via ion pair activated complex is proposed for the reaction.

The corrosion inhibition of copper in the presence of 10-3 M of imidazole derivatives; Imidazole (IM), 2-Methyle imidazole (MIM), Benzimidazole (BIM) has been investigated in 1.0 M H2SO4 solution using  potentiodynamic  polarization and electrochemical impedance spectroscopy (EIS). Relationship between molecular structure and their inhibition efficiency was elucidated by quantum chemical calculations using the density functional theory (DFT) at the B3LYP/6-31+G(d,p) level. Inhibition efficiency of these compounds which has been evaluated via experimental methods was accorded with reported theoretical ones, and following the same order as BIM ˃ MIM ˃ IM.

it has been challenging to adequately investigate the properties of nanosystems with radical nature using conventional electronic structure methods. We address this challenge by calculating the electronic properties of linear carbon chains (l-cc[n]) and cyclic carbon chains (c-cc[n]) with n = 10-100 carbon atoms, using thermally-assisted-occupation density functional theory (TAO-DFT). For all the cases investigated, l-cc[n]/c-cc[n] are ground-state singlets, and c-cc[n] are energetically more stable than l-cc[n]. the electronic properties of l-cc[n]/c-cc[n] reveal certain oscillation patterns for smaller n, followed by monotonic changes for larger n. For the smaller carbon chains, odd-numbered l-cc[n] are more stable than the adjacent even-numbered ones; c-cc[4m + 2]/c-CC[4m] are more/less stable than the adjacent odd-numbered ones, where m are positive integers. As n increases, l-cc[n]/c-cc[n] possess increasing polyradical nature in their ground states, where the active orbitals are delocalized over the entire length of l-cc[n] or the whole circumference of c-cc[n]. Carbon is the most versatile element in forming various structures. In bulk phase, graphite and diamond, which are well-known materials, have been used for centuries. In nanoforms, fullerenes and graphene have been studied in detail for decades. In general, nanostructures can be classified into three categories: zero-dimensional (0D), one-dimensional (1D), and two-dimensional (2D) nanomaterials. Carbon forms all these nanostructures with unique shapes and properties. Over the past few decades, carbon nanomaterials have been widely studied, and applied in diverse industries 1-3. A number of carbon nanostructures have been synthesized and applied in different fields. The 0D carbon nanomaterials include clusters, quantum dots, nanoflakes, and buckyballs 3. Among them, the C 60 fullerene molecule (containing 12 pentagons and 20 hexagons), where the carbon atoms are sp 2-sp 3-hybridized, has been a popular carbon nanomaterial 1. The discovery of C 60 has led to the flourishment of carbon nanomaterials in various ways. Graphite is a bulk layered material, where the sp 2-hybridized carbon atoms in each layer are arranged in a hexagonal lattice. The 2D carbon nanomaterial, graphene, can be obtained by mechanically exfoliating a single layer of carbon atoms from graphite 2. Thus, graphene, which is a perfect arrangement of hexagons made up of sp 2-hybridized carbon atoms in a 2D planar surface, can be the thinnest (i.e., single-atom-thick) material synthesized ever. Graphene is a zero-gap semiconductor or semimetal with massless Dirac fermions with linear dispersion at low energy. Because of the Dirac-cone feature, graphene has huge potential in electronics applications 2. The discovery of graphene has also led to the discovery of other 2D materials. Besides, if a graphene sheet can be rolled up to form a seamless cylinder, one obtains a carbon nanotube (CNT), which belongs to the class of 1D nanostructures. Note that CNTs were first observed by Iijima in 1991 4 , well before the separation and characterization of graphene. On the basis of the direction of rolling (chirality), CNTs can be classified into three groups: chiral, zigzag, and armchair CNTs, which can have rather different electronic properties. Apart from these well studied carbon nanoallotropes, linear carbon chains (i.e., also belonging to the class of 1D nanostructures), where the carbon atoms are sp-hybridized, have recently gained much attention because of their interesting physical and chemical properties 5-18. A linear carbon chain consisting of n carbon atoms (for brevity, denoted as l-CC[n] (see Fig. 1a)) is an ideal 1D carbon nanomaterial. Kroto et al. originally designed an experiment for explaining the formation mechanism of carbon chains in outer space, which led to

Non-empirically tuning the range-separation parameter (ω) of long-range corrected (LC) hybrid functionals in improving the accuracy of vertical ionization potentials (IPs), vertical electron affinities (EAs), and fundamental gaps (FGs) is investigated. Use of default ω values gives the best overall property predictions employing the Δ self-consistent field (ΔSCF) approach, if sufficiently large basis set is used. Upon tuning, IP (HOMO) (i.e., the IP estimated from the negative of HOMO energy via DFT Koopmans' theorem) with the IP (ΔSCF) (i.e., the IP obtained from the ΔSCF approach) the accuracy of IP (HOMO) significantly improves however a reciprocal phenomenon is not observed. An interesting observation is that EA (LUMO) (i.e., the EA estimated from the negative of LUMO energy) is more accurate than EA (ΔSCF), if the ω value is in the range of 0.30 to 0.50 bohr −1 .

Solving multi-particle systems is an important topic in quantum chemistry and condensed matter physics. In this article I focus on finding the ground states and ground state energies for the He-H+ and H2O molecules using the power of quantum computing. I will be using a variational quantum eigensolver algorithm (VQE) which will run on both a simulation of a quantum computer and on the IBM quantum computer. I will compare the results against the exact ground state energy found through other classical means. The H2O simulations were run on Nottingham's High Performance Computer (HPC).

La Nanotecnología está rápidamente cambiando el paradigma de los sistemas de fabricación de una estrategia "top-down" a una estrategia "bottom-up" [1]. Estos procesos que siguen la estrategia "bottom-up" explotan el "autoensamblaje" del material involucrado. Uno de tales materiales con la habilidad de auto ensamblarse es el ADN [2, 3]. La creación de sistemas molecu

Schistosomiasis affects million people and its control is widely dependent on a single drug, praziquantel. Computational chemistry has led to the development of new tools that predict molecular properties related to pharmacological potential. We conducted a theoretical study of the imizadole alkaloids of Pilocarpus microphyllus (Rutaceae) with schistosomicidal properties. The molecules of epiisopiloturine, epiisopilosine, isopilosine, pilosine, and macaubine were evaluated using theory models (B3lyp/SDD, B3lyp/6-31+G(d,p), B3lyp/6-311++G(d,p)). Absorption, distribution, metabolization, excretion, and toxicity (ADMET) predictions were used to determine the pharmacokinetic and pharmacodynamic properties of the alkaloids. After optimization, the molecules were submitted to molecular docking calculations with the purine nucleoside phosphorylase, thioredoxin glutathione reductase, methylthioadenosine phosphorylase, arginase, uridine phosphorylase, Cathepsin B1 and histone deacetylase 8 e...

A one-pot multi-components synthesis of a series of novel pyrimido(1,2-a)benzimidazoles (4a- j) was achieved from acetoacetamide, aromatic aldehydes and 2-aminobenzimidazole with high yield and purity. The structures of the newly synthesized pyrimido(1,2-a)benzimidazoles (4a-j) were supported by FTIR, PMR and mass spectral data. All the newly synthesized compounds were tested for antimicrobial activity.

The coupling reaction of the diazonium salt solution of the 6aminocoumarins 1a-c with ethylacetoacetate has afforded the corresponding hydrazones 2a-c, which on further intramolecular cyclisation with PPA yielded the corresponding 3H,7H,10H-9acetyl-3,10-dioxopyrano[2,3-f]cinnolines 3a-c. Reaction of 3a-c with hydrazine hydrate has afforded the 3H,11H-9-methyl-3oxopyrano[2,3-f]cinnolino[3,4-c]pyrrazoles 4a-c, which on Mannich condensation with formaldehyde and morpholine yield the corresponding 3H-9-methyl-3-oxo-11-(N-methylenemorpholino)pyrano[2,3-f]cinnolino[3,4-c] pyrrazoles 5a-c. The reaction of 3a-c with phenyl hydrazine and 4-methyl-7-methoxycoumarin-6-ylhydrazine hydrochloride afforded 3H-9-methyl-3-oxo-11phenyl pyrano[2,3-f]cinnolino[3,4-c]pyrrazoles 6a-c and 3H-9methyl-3-oxo-11-(4-methyl-7-methoxy-2-oxo-2H-[1]-benzopyran-6-yl)pyrano[2,3-f]cinnolino[3,4-c]pyrrazoles 7a-c, respectively. The structures of the compounds 2-7a-c have been established on the basis of spectral and analytical data. All the above compounds have been screened for their antimicrobial activities and are found to possess significant antibacterial and antifungal activities.

Molecular interactions between uracil and nitrous acid (U-NA) [C 4 N 2 O 2 H 4 ANO 2 H] have been studied using B3LYP, B3PW91, and MP2 methods with different basis sets. The optimized geometries, harmonic vibrational frequencies, charge transfer, topological properties of electron density, nucleus-independent chemical shift (NICS), and nuclear magnetic resonance one-and two-bonds spin-spin coupling constants were calculated for U-NA complexes. In interaction between U and NA, eight cyclic complexes were obtained with two intermolecular hydrogen bonds N(C)HU…N(O) and OH NA …O U. In these complexes, uracil (U) simultaneously acts as proton acceptor and proton donor. The most stable complexes labeled, UNA1 and UNA2, are formed via NH bond of U with highest acidity and CO group of U with lowest proton affinity. There is a relationship between hydrogen bond distances and the corresponding frequency shifts. The solvent effect on complexes stability was examined using B3LYP method with the aug-cc-pVDZ basis set by applying the polarizable continuum model (PCM). The binding energies in the gas phase have also been compared with solvation energies computed using the PCM. Natural bond orbital analysis shows that in all complexes, the charge transfer takes place from U to NA. The results predict that the Lone Pair (LP)(O) U ! r*(OAH) and LP(N(O) NA ! r*(N(C)AH) U donor-acceptor interactions are most important interactions in these complexes. Atom in molecule analysis confirms that hydrogen bond contacts are electrostatic in nature and covalent nature of proton donor groups decreases upon complexation. The relationship between spin-spin coupling constant (1h J H … Y and 2h J H … Y) with interaction energy and electronic density at corresponding hydrogen bond critical points and H-bonds distances are investigated. NICS used for indicating of aromaticity of U ring upon complexation. V

Zinc telluride (ZnTe) quantum dots (QDs) were synthesized by a unique supersaturation-controlled aqueous route. For a given pH, increasing the degree of initial supersaturation led to a decrease in the average diameter (davg) of the QDs and increased monodispersity. Three samples of ZnTe QDs having average sizes of 0.8, 1.7, and 2.2 nm were synthesized (hence named ZnTe_0.8, ZnTe_1.7, and ZnTe_2.2). Nonlinear absorption (NLA) and nonlinear refraction (NLR) of these colloidal ZnTe QDs of different sizes were investigated by the Z-scan technique using a continuous He–Ne laser (632.8 nm, 15 mW). Isotropic assembly of ZnTe_2.2 leads to the formation of nanoballs (hence named ZnTe_NB). The NLA profile of smaller QDs, ZnTe_1.7 and ZnTe_0.8, was found to follow a three-photon absorption (3PA) model, while relatively bigger QDs, ZnTe_2.2, followed a two-photon absorption (2PA) model. On moving from ZnTe_0.8 to ZnTe_1.7, the three-photon absorption coefficient (γ) decreases by 26% (3.00 × 10–4 → 2.21 × 10–4 cm3/MW2). The two-photon absorption coefficient (β) for ZnTe_2.2 is 0.3 cm/MW. For a 63% decrease in average diameter (2.2 → 0.8 nm), the refractive index (n2) increases by 45% (2.48 × 10–2 → 3.6 × 10–2 cm2/MW). Overall, the NLR coefficient shows a decreasing trend with size. Upon isotropic self-assembly, ZnTe_NB, there is a significant increase in the NLR coefficient by 40% (2.48 × 10–2 → 3.48 × 10–2 cm2/MW) and a simultaneous decrease in the NLA coefficient by 45% (0.3 → 0.166 cm/MW). The figure of merit was also determined for all of the samples, and it was found that ZnTe_2.2 and ZnTe_0.8 were best suited for all-optical device applications. Further, the self-assembled nanostructures are promising for making optical waveguides for supercontinuum generation (SCG).

The paper collects the answers of the authors to the following questions: Is the lack of precision in the definition of many chemical concepts one of the reasons for the coexistence of many partition schemes? Does the adoption of a given partition scheme imply a set of more precise definitions of the underlying chemical concepts? How can one use the results of a partition scheme to improve the clarity of definitions of concepts? Are partition schemes subject to scientific Darwinism? If so, what is the influence of a community's sociological pressure in the “natural selection” process? To what extent does/can/should investigated systems influence the choice of a particular partition scheme? Do we need more focused chemical validation of Energy Decomposition Analysis (EDA) methodology and descriptors/terms in general? Is there any interest in developing common benchmarks and test sets for cross‐validation of methods? Is it possible to contemplate a unified partition scheme (let us...

A new series of 3-methyl-6-[1-(pyrimidin-4-yl)ethyl]-5 H-pyrimido[5,4- e][1,2,4]triazolo[3,4- b][1,3,4]thiadiazine derivatives was synthesised through the condensation reaction of 5-bromo-4-[1-(5-bromo-2,6-dichloropyrimidin-4-yl)ethyl]-2-chloro-6-methylpyrimidine and 4-amino-5-methyl-4 H-1,2,4-triazole-3-thiol.