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The machine learning potential (MLP) is proposed based on the representation of the environment through moment tensors to model the diamond phase nucleation in misoriented bilayer graphene. MLP is trained on a set of graphene structures, 2D diamond, and their hydrogenated modifications obtained by density functional theory computations. Learned MLP accurately reproduces energies and strengths of these structures and correctly describes hydrogenation of bilayer graphene and the formation of interlayer bonds. Growth of the diamond phase in bigraphene with a 5° misorientation of layers is studied using MLP. It is found that the formation energy increases with an increase in the number of hydrogen atoms, which indicates hydrogen cluster nucleation on the surface of bilayer graphene. Hydrogenation of the system leads to the growth of the cubic diamond region up to the AA′ stacking promoting the formation of lonsdaleite with the surface. This fact allows us to draw the conclusion about the adequacy of the potential obtained. [ABSTRACT FROM AUTHOR]

We report a three-stage scheme (1) Pbt–NH2 + CS2 → (Pbt–NH)2C=S (1) (Pbt = 4-(1′,3′-benzothiazole-2′-yl)phenyl), (2) 1 + PPh3 + I2 → Pbt–N=C=N–Pbt (2), (3) 2 + Ph2PH → (Pbt–N)(Pbt–NH)CPPh2 (3) for the synthesis of a novel luminescent phosphoguanidine 3 with an unprecedentedly high yield (90%) at the last catalyst-free stage. It is demonstrated by the density functional theory (DFT) method that high reactivity of 2, leading to such an yield, is explained by a high electrostatic potential at the central carbon atom. For 3, two polymorphs 3α, 3β and a solvatomorph 3γ·THF are prepared. The structures of 2, 3α, 3β, and 3γ·THF are determined by single-crystal XRD. The tendency of crystals of different phenylbenzothiazole derivatives to form different conformations is explained by the computational (DFT) data indicating that the energy change of the molecule of 3 considered as a function of the torsion angle between phenyl and benzothiazole fragments does not exceed 2 kJ/mol in the –15...30° range. Photophysical properties of 3β and 3γ·THF phases are studied. It is shown that these compounds exhibit photoluminescence with an emission maximum at 510 nm. [ABSTRACT FROM AUTHOR]

Carboxylate molecules are distinguished as potential compounds in the largely emergent chemical world of heterocyclic compounds showing alike pharmacological characteristics. The knowledge of a mixture of synthetic pathways and different physicochemical parameters of such compounds are of special interest to medicinal chemists to produce combinatorial collections and carry out in-depth searches of lead molecules. Among various groups of the compounds studied, carboxylate moieties stand out as unique in features due to their biological, pharmacological, and medicinal properties. The synthesis, crystal structure, conformation, and density functional theory study of the (4-(4-nitrophenyl)-9-(phenylsulfonyl)-9H-carbazole-2,3-diyl)bis(p-tolylmethanone) derivative are reported in detail. The carboxylate moiety is in the planar conformation with C–H⋯O hydrogen bonds and Van der Waals forces. Density functional theory is utilised to investigate the carboxylate derivative. Similar to co-crystal ligands, carboxylate compounds exhibit potent interactions with the target protein. The supramolecular properties are measured and validated using Hirshfeld surface studies. [ABSTRACT FROM AUTHOR]

In this study, we investigate the reaction between water and the cis and trans limonene oxide mixture in the presence of ethyl carbamate ((R)-N-(α-methyl-benzyl)ethyl-carbamate), producing (1 R, 2 R, 4 R)-limonene-1,2-diol and trans limonene oxide. This study is carried out using the quantum mechanical density functional theory (DFT) method B3LYP-D3/6-31+G (d,p) to theoretically explain that 1,2-limonene diol is the hydrolysis product derived from cis limonene oxide, with trans limonene oxide not reacting (regioselectivity). For this reason, we exploit Fukui's frontier molecular orbital theory (FMO), local softness and local hardness ratios, transition states of the obtained products, the Fukui indices, and the thermodynamic quantities (enthalpy, entropy, free energy calculations). The theoretical results effectively elucidate the observed regioselectivity and corroborate the experimental findings. [ABSTRACT FROM AUTHOR]

Structural, electronic, and vibrational properties of phosphates LiCdPO4, NaCdPO4, RbCdPO4, CsCdPO4 are studied by density functional theory and Hartree–Fock methods using the CRYSTAL17 code in the LCAO basis set with gradient PBE, PBEsol and hybrid PBE0, PBEsol0 functionals. It is shown that the crystal structures contain infinite zigzag chains consisting of [CdO6] octahedra and [PO4] tetrahedra inside which there are alkali metal atoms. By the Gaussian broadening of normal long-wave modes IR absorption and Raman spectra are calculated. Differences in the number of spectral bands, their polarization and intensities are related to different symmetry space groups of the crystals. [ABSTRACT FROM AUTHOR]

The parameterization of machine learning potentials (MLP) for precise characterization of the interaction between carbon atoms in graphite and diamond phases is described. The training set consisted of various allotropic forms of carbon and their compounds. The MLPs are trained using forces, energies, and stress tensors obtained from ab initio simulations. It is shown that the MLPs can accurately reproduce elastic properties and structural parameters of carbon phases. However, the MLPs also predict some unphysical behavior due to the training set limitations and the lack of long-range interactions in the MLPs. In spite of these limitations, MLPs are a promising tool for the accurate characterization of diamond nucleation in graphite. [ABSTRACT FROM AUTHOR]

Adsorption of various glycerol conformations at Brønsted sites in mordenite is studied by the density functional theory. It is shown that the adsorption energy depends on the initial conformation of the glycerol molecule and ranges from –44.0 kcal/mol (ββ conformation) to –64.7 kcal/mol (αγ conformation). In some cases, the glycerol molecule switches its conformation as a result of nanoconfinement. It is shown that the most energetically favorable adsorption of glycerol on mordenite proceeds via the primary OH group. High adsorption energy is due to the proton transfer from the zeolite Brønsted site to glycerol as a result of the hydrogen bond formation and also due to the formation of up to four additional hydrogen bonds with oxygen atoms of the zeolite framework. As a result, the backbone of the adsorbed molecule deforms, which fact should affect the course of chemical reactions involving glycerol. [ABSTRACT FROM AUTHOR]

Geometric characteristics and the thermodynamic stability of zinc(II) pivalate derivatives with functionalized N-heterocyclic carbenes R–NHC–X (R= Dipp, t-Bu, Mes, i-Pr; X = OMe, H, Br, CN) are studied using the density functional theory (DFT B3LYP/Def2-TZVP). It is shown that formation of coordination compounds ([Zn(Piv)2(R–NHC–X)] or [Zn(Piv)2(R–NHC–X)2]) of various compositions is mainly determined by steric hindrances created by the bulky groups R at the nitrogen atoms in carbenes. The introduction of electron-active groups X into carbene positions 4 and 5 slightly diminishes the stability of the resulting adducts. [ABSTRACT FROM AUTHOR]

For the last few years technical improvements of compositions and preparation procedures for perovskite-based solar cells have remarkably enhanced their energy conversion efficiency. Crystal and electronic structures together with ion diffusion in partially substituted cubic methylammonium (MA) perovskite based on lead halide MA0.5X0.5PbI3, where X is the cation, are theoretically investigated using density functional theory and molecular dynamics methods. The electronic structure of partially substituted perovskites studied is similar to the MAPbI3 structure, however, the band gap changes compared to their structures. Partial MA substitution distorts the lattice, which prevents MA or X diffusion between A sites in the perovskite crystal. The partial cation substitution affects the electronic structure and distorts the crystal lattice of perovskite, which makes it possible to control the optical properties of the material in different spectral regions and to influence the electronic composition of defects. [ABSTRACT FROM AUTHOR]

Heterospin compounds based on stable radical-containing triangular polycyclic hydrosilicons are simulated using the density functional theory (DFT B3LYP/6-311++G(d,p)). It is shown that the nature and strength of exchange interactions depend on the size of the silicene core and the type of radical substituents. The proposed high-spin ground-state molecules, exhibiting strong ferromagnetic coupling of unpaired electrons, and systems with non-interacting paramagnetic centers can be considered as promising building units for molecular electronics devices. [ABSTRACT FROM AUTHOR]

The structures of phosphorus clusters with the number of atoms from 17 to 220 and their stability are studied theoretically. To calculate total energies of clusters a model is used that allows the highly accurate reproduction of density functional theory results. Calculations show that the most energetically favorable clusters Pn with 17 ≤ n ≤ 90 are single-stranded structures. At 91 ≤ n ≤ 125 these systems compete with double strands of fibrous phosphorus, and at n ≥ 126 fibrous phosphorus clusters become more favorable. The application of local stability criteria makes it possible to reveal the most stable clusters that are most likely to occur in the experiment. [ABSTRACT FROM AUTHOR]

The structures of phosphorus clusters with the number of atoms from 17 to 220 and their stability are studied theoretically. To calculate total energies of clusters a model is used that allows the highly accurate reproduction of density functional theory results. Calculations show that the most energetically favorable clusters Pn with 17 ≤ n ≤ 90 are single-stranded structures. At 91 ≤ n ≤ 125 these systems compete with double strands of fibrous phosphorus, and at n ≥ 126 fibrous phosphorus clusters become more favorable. The application of local stability criteria makes it possible to reveal the most stable clusters that are most likely to occur in the experiment. [ABSTRACT FROM AUTHOR]

The pseudo-potential PAW method of the density functional theory is employed to study the localization of superstoichiometric oxygen in ferrite CaBaFe4O7 with the orthorhombic swedenborgite structure. The geometric characteristics of oxygen defects are determined by the crystal lattice relaxation procedure. It is shown that the formation of defects in calcium and barium coordination are energetically unfavorable. Oxygen intercalation into structural trigonal iron-oxygen and Kagomé layers is more favorable. In these layers, two edge-sharing Fe2O5 bipyramides are formed instead of FeO4 tetrahedra connected via one oxygen atom. The structural instability of ferrite CaBaFe4O7 is shown to be caused by the population of anti-bonding 2p O states during oxygen intercalation. The asymmetric location of the intercalated oxygen ion relative to the neighboring iron ions promotes the appearance of local electric polarization, which can induce ferroelectric effects in the presence of ferromagnetic order. [ABSTRACT FROM AUTHOR]

A PEPPSI-type imidazolidin-2-ylidene-based palladium(II) complex was prepared according to literature. Detail molecular structure of this complex has been confirmed by X-ray diffraction analysis and supplemented by theoretical calculations. Also, electronic properties of the complex were investigated by UV-Vis spectroscopy. The complex under scrutiny was found to adopt a trans arrangement with square-planar geometry. Furthermore, theoretical structure and spectroscopic data were obtained using density functional theory (DFT/HSEH1PBE) method and SDD basis set, and compared with the experimental data. In general, the theoretical findings were in line with the experimental outcomes. [ABSTRACT FROM AUTHOR]

In this study, the title compound was synthesized, and its structure was illuminated by X-ray diffraction, 1H and 13C NMR spectroscopy methods. X-ray study shows that the crystal structure is stabilized by intermolecular C–H⋯Cl hydrogen bonds. Quantum mechanical approach was carried out to study the molecular structure, NMR spectra and stability of the compound by using Density Functional Theory (DFT) with HSEH1PBE functional and LanL2DZ basis set. Hirshfeld surface analysis was used as theoretical approach to assess driving force for crystal structure formation via the intermolecular interactions in the crystal lattice. In addition, chemical reactivity and kinetic stability of the molecule based on frontier molecular orbital analysis were investigated. [ABSTRACT FROM AUTHOR]

Five membered hetrocyclic moieties have been proved to possess strong biological activities. The compounds 5-(4-chlorophenyl)-3-(coumarin-3-yl)-1H-pyrazole and 5-(4-chlorophenyl)-3-(coumarin-3-yl)isoxazole were synthesized and characterized by IR, 1H and 13C NMR, and high-resolution mass spectrometry. The structural optimization and the interpretation of theoretical vibrational spectra is made by the Gaussian09 software and the B3LYP/6-31G density functional theory (DFT) approach. Bond lengths, bond angles have all been studied. The Mulliken population analysis on atomic charges is performed. The thermodynamic stability in the ground state and reactivity of the compounds in the excited state are explained by the HOMO–LUMO energy gap. The molecular docking study is carried out using PyRx. The anti-oxidant activities of the derivatives were determined by DPPH scavenging assay. The synthesized compound showed remarkable antioxidant activity. The newly synthesized compounds were tested for their anticancer activity against HeLa cell line in vitro by MTT assay method. [ABSTRACT FROM AUTHOR]

The Friedel–Crafts alkylation of benzene with cyclohex-4-ene-1,2-dicarboxylic acid is studied by quantum chemical methods. Parameters of the starting compounds, products, and transition compounds are calculated by density functional theory (DFT) and ab initio Hartree–Fock (HF) methods. Theoretical enthalpies of formation show that it is more favorable for (1R,2S,4R)-4-phenylcyclohexane-1,2-dicarboxylic acid (syn-product) than for (1R,2S,4S)-4-phenylcyclohexane-1,2-dicarboxylic acid (anti-product). The data obtained are confirmed by HELC and 1H-1H NOESY spectroscopy. According the to results of the quantum chemical study and the experiment, the Friedel–Crafts alkylation of benzene with cyclohex-4-ene-1,2-dicarboxylic acid and subsequent modifications of the product are regio- and stereoselective. [ABSTRACT FROM AUTHOR]

Reaction pathways are found for electronic structural rearrangements in thiometallates [MS4]n– (M = V, n = 3; Mo, n = 2; Re, n = 1), which do not contradict the hypothesis about the possible electron transfer from sulfide ions S2– to metal centers with a corresponding decrease in metal atomic charges and the formation of disulfide ions of the (S2)2– type. The obtained results are compared with similar results for the same series of oxometallates [MO4]n–. [ABSTRACT FROM AUTHOR]

The effect of pressure on the structure and electronic properties of the α-phase of sodium amide is studied by ab initio calculations based on the density functional theory. Linear compressibilities of α-NaNH2 are calculated, and thus, the negative linear compressibility (–12 TPa–1) is found due to an increase in the ∠(N–Na–N) angle with increasing pressure. Based on the quantum topological analysis of the electron density, interatomic interactions are investigated. Changes in α-NaNH2 band gaps under pressure are calculated using the hybrid functional. [ABSTRACT FROM AUTHOR]

The 7-azaindoles derivatives, as a major category of compounds, show a widespread of biological activities. The compound 5-bromo-1-tosyl-1H-pyrrolo[2,3-b]pyridine (1) was obtained by one-step substitution reaction. In the meantime, the structure of compound 1 was confirmed by 1H NMR, 13C NMR, FTIR and X-ray diffraction. The optimized molecular crystal structure was preliminarily determined by using density functional theory (DFT) and compared with the X-ray diffraction values. In addition, more physical and chemical properties of compound 1 have been studied by further studying the molecular electrostatic potential and frontier molecular orbital of compound 1. [ABSTRACT FROM AUTHOR]

Electronic structures of four tetrafluoro derivatives of zinc(II) phthalocyanine with substituents at non-peripheral positions as well as their valence electronically excited singlet states are calculated by density functional theory methods. For the structural isomers under study intense electronic transitions to which characteristic Q and B absorption bands correspond are analyzed. The UV-Vis absorption spectrum of the considered compound is modeled using the calculated data for the relative thermodynamic stability of the isomers. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) and the Møller–Plesset expansion (MP2) calculations were benchmarked to characterize the structure of novel derivatives of carbene hydroxymethylene. In this regard, eleven numbers of primary aldehydes including formaldehyde, acetaldehyde, formyl chloride, 2-chloroacetaldehyde, formyl fluoride, 2-fluoroacetaldehyde, formic acid, propionaldehyde, glyoxal, methyl formate, and formyl bromide (1H–11Br) were scrutinized, at the B3LYP/6-311++G(3d,3p) level of theory. Thereafter, the process of keto-enol tautomerism via a [1,2]-H-shift of 1H–11Br was monitored to reach their corresponding enol forms (1P–11P). For all species (except for one structure), the TS involves a triangle structure of C–O–H and yields cis or trans isomers of a singlet ground-state (S) carbene that contrasts the multiplicity of ordinary carbenes. The bond dissociation energy (BDE) calculations were carried out for the homolytic cleavage of C–H bonds of 1H–11Br. The AIM, as a promising analysis that definitely reveals the nature of the bond, was conducted to characterize the eigenvalues at the bond critical points (BCPs). In addition, the relation between the Hammett equation and thermodynamic parameters was obtained. Our investigation suggests new stable S derivatives of carbene hydroxymethylene that can be isolated. [ABSTRACT FROM AUTHOR]

Structure, longitudinal elasticity, and electronic properties of endohedral assembled composites of single-walled carbon nanotubes and a one-dimensional crystal KI - KI@CNT - are studied by the density functional theory method. It is established that electronic properties of defect-free composites KI@CNT are predetermined by the electronic properties of the parent nanotube. The introduction of K or I vacancies stimulates the charge transfer between the encapsulate and the nanotube, accompanied by increasing concentration of electron or hole charge carriers in the nanotube. Young′s moduli of KI@CNT are 20-50% lower than those of parent nanotubes, irrespective of their chirality type and presence of atomic vacancies in the KI encapsulate. These results approve the preservation of high strength of carbon nanotubes within their composites with halides and provide a helpful guideline for applications of nanotubes as delivery agents, nanoreactors, etc. [ABSTRACT FROM AUTHOR]

Ethyl 5-(trimethylsilyl)-1-1H-pyrazole-3-carboxylate is a broad-spectrum bioactive derivative of pyrazole. In this study, this compound was synthesized, and its purity was analyzed using IR, 1H NMR, 13C NMR, and MS. At the same time, the single crystal of the title compound was determined through X-ray diffraction analysis. Moreover, the optimal structure of the molecule was calculated using density functional theory (DFT) calculations and compared with the X-ray diffraction data. The results of conformational analysis revealed that the optimized molecular structure obtained from DFT calculations was equivalent to that obtained from X-ray diffraction analysis. The crystal structure determined using single crystal diffraction is consistent with that of the title compound. In addition, the molecular electrostatic potential and leading molecular orbitals of the title compound were further investigated using DFT calculations, and insights into some of the physical and chemical properties of the compound were achieved. [ABSTRACT FROM AUTHOR]

Mechanism of (E,Z)-1,3-diaryl-2-azadienes stereoselective formation from N-benzylketimines and acetylene in the superbasic KOt-Bu/DMSO environment is considered within the density functional theory on the example of N-benzyl-1-phenylethane-1-imine vinylation. [ABSTRACT FROM AUTHOR]

The ab initio study of tubular nanostructures formed by folding monatomic diamond-like L4, L3-6, and L3-4-6 layers is reported. Density functional theory calculations of the structure show that only polyprismatic tubes based on the L4 layer, designated as (n, 0)L4, and characterized by the n/mmm point group can exist. The other tubular nanostructures are unstable even at a temperature close to 0 K and transform into amorphous or hybrid nanostructures as well as carbon nanotubes. Diameters of the studied (n, 0)L4 tubes range from 0.1997 nm to 0.4667 nm; the translation parameter varies from 0.1622 nm to 0.1634 nm. By the molecular dynamics simulation it is found that an isolated (5, 0)L4 tube having the minimum total energy can be stable at least up to 150 K. In the case of the synthesis of bundles of the most stable L4-diamond-like tubes, they can be unambiguously identified using the calculated X-ray absorption spectrum, the Raman spectrum, and the powder X-ray diffraction pattern. [ABSTRACT FROM AUTHOR]

First example of a nitrosoruthenium complex with a nitroxyl radical is prepared by the interaction of Na2RuNOCl5 with 2-(3-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-l-H-imidazole-1-oxyl-3-N-oxide (L) in acetonitrile at 85°C. The reaction product is the Na[RuNOCl4L] monosubstituted complex where the nitroxyl radical is coordinated by the nitrogen atom of the pyridine ring and occupies a cis position with respect to the nitroso group. The EPR data show that the spin density distribution in the radical almost does not change upon the coordination. The combination of electronic spectroscopy and density functional theory (DFT) data show that transitions at 500-700 nm are determined by the intraligand electron transfer in the nitroxide radical and by the electron transfer from the nitroxyl radical to the orbitals of the Ru–NO fragment. [ABSTRACT FROM AUTHOR]

Interaction of the palladium(II) benzonitrile complex [Pd(PhCN)2Cl2] with glyoxal-bis(2-hydroxy-3,5-di-tert-butylphenyl)imine (H2L) induces intramolecular rearrangement of H2L into the corresponding tetrahydrobenzoxazinobenzoxosine (L′), and the coordination of the latter to Pd(II) leads to the formation of [Pd(L′)Cl2]·(CH3)2CO (1·(CH3)2CO). The crystal structure of this compound is determined by XRD. The Pd atom in the structure occurs in a square planar environment of two Cl atoms and two N atoms of the L′ ligand. Quantum chemical calculations within the density functional theory are conducted; the electronic structure of 1 is studied. The Pd–N and Pd–Cl bonds are shown to be intermediate type bonds. Orbitals of N–Pd–Cl three-center bonds are discovered using the NBO analysis. The formation of such three-center bonds can be represented as a result of the electron density donation from the orbitals of nitrogen lone pairs to the σ* orbitals of Pd–Cl bonds. [ABSTRACT FROM AUTHOR]

The structure and electronic properties of crystalline purine are studied by ab initio calculations based on the density functional theory with regard to the dispersion interaction depending on the pressure up to 1 GPa. Purine is shown to be characterized by a negative linear compressibility, and its mechanism is determined at the microscopic level. Elastic constants, linear compressibilities, and elastic moduli of purine are calculated. Based on the electron density topological analysis, the hydrogen bond between purine molecules is investigated. The band gap of purine is calculated and its change with pressure is predicted. [ABSTRACT FROM AUTHOR]

The crystal structure of the NbO compound can be described as a vacancy-ordered derivative of the NaCl (B1) structure type with a concentration of structural vacancies of 25 at.% simultaneously in two sublattices. It was previously supposed that as the pressure increased, the vacancy-free NbO crystal with the B1 structure stabilized. In this work, effects of the pressure and the concentration of vacancies on the NbO structure are investigated by density functional theory methods. A new vacancy-free NbO phase with the rhombohedral crystal structure is found, its thermodynamic stability is evaluated, and the electronic structure is analyzed. It is demonstrated that with an increase in the pressure, rhombohedral NbO must be enthalpically stabilized rather than the vacancy-free NbO phase with the B1 structure. [ABSTRACT FROM AUTHOR]

Atomic and electronic structures of cyclic organosilicon compound 9,9,10,10-tetraethynyl-9,10-dihydrodisilaanthracene are studied by the density functional theory. The calculated structural parameters of this molecule are compared with the respective crystallographic values for a series of dihydrosilanthrene derivatives. Based on the calculations, the electronic structure of the studied compound is analyzed and the results are in good agreement with the X-ray emission spectroscopy data. [ABSTRACT FROM AUTHOR]

Structural parameters and relative Gibbs free energies are calculated by density functional theory methods for four tetrafluoro derivatives of zinc(II) phthalocyanine with substituents in non-peripheral positions. It is established that the least symmetrical isomer exhibits the highest thermodynamic stability under standard conditions. It is shown that the experimental IR spectrum of the studied compound contains contributions from the IR spectra of the corresponding isomers; a theoretical approach for the spectrum simulation is proposed. [ABSTRACT FROM AUTHOR]

A pair of C9-C10-trans-C10-artemisinin-purine hybrids (A and B) were stereoselectively synthesized under a protonic acid condition, which were structurally characterized by 1H NMR, 13C NMR, IR, HRMS and single crystal X-ray diffraction. Further structural analyses were conducted by Density Functional Theory (DFT) Calculation. DFT-optimized structures of A and B were consistent with X-ray data, so were DFT-based molecular vibrations with IR data. Intramolecular hydrogen bonds played significant role in stabilization of crystal structures both A and B which were chemical stable. Finally, antiproliferative effects of A and B were evaluated in human breast cancer cell lines T47D and MDA-MB-436. The anticancer activities of two novel compounds were equivalent to the positive control (mercaptopurine) towards the ER+ cell line T47D, while A was more potent than the positive control in triple-negative-type MDA-MB-436 cells. [ABSTRACT FROM AUTHOR]

The organometallic complex [Pd(dpp-bian)(C4(COOMe)4)]·(C2H5)2O (1·(C2H5)2O) is obtained by the interaction of [Pd2(dba)3] (dba = dibenzylideneacetone) with dimethyl ether of acetylenedicarboxylic acid and 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian) in the 1:4:2 molar ratio. During the oxidative addition reaction the 1,2,3,4-tetrakis(methoxycarbonyl)buta-1,3-dienyl dianion is formed from two molecules of dimethyl ether of acetylenedicarboxylic acid. This dianion is coordinated to palladium(II) via 1 and 4 carbon atoms with the formation of the palladacyclopentadienyl moiety. The crystal structure is determined by the single crystal X-ray diffraction analysis. The 1·(C2H5)2O compound crystallizes in the orthorhombic crystal system (Pbca) with unit cell parameters a = 16.9069(3) Å, b = 23.5618(6) Å, c = 23.8902(7) Å, V = 9516.83(40) Å3. Each palladium atom has an almost square planar environment composed of two dpp-bian nitrogen atoms and two carbon atoms of the (C4(COOMe)4)2– anion. The cyclic voltammogram of 1 in acetonitrile reveals irreversible oxidation at Ea = 1.43 V, reversible reduction at E1/2 = 0.62 V, and irreversible reduction at Eb = 1.52 V. The electronic structure of complex 1 is studied within the density functional theory. [ABSTRACT FROM AUTHOR]

A novel sandwich-like heterotrinuclear [Zn(II)2Mn(III)] complex, [{Zn(L)Cl}2Mn]Cl, has been constructed successfully from a bicompartmental 3-MeOSalphen ligand (H2L), N,N′-bis(3-methoxy-salicylidene)phenylene-1,2-diamine. The chemically obained structure was determined through single crystal X-ray diffraction and spectrochemical (IR and UV-Vis) analyses. The structural studies revealed that characteristic inner N2O2 compartment of H2L is occupied by Zn(II) atom and outer O2O2 compartment is coordinated by Mn(III) atom in the Zn(II)–Mn(III) complex. The Zn(II)–Mn(III) complex can be used as a potential light-emitting material owing to the fluorescent property. In addition, density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed to take insight of experimental electronic spectra. Interaction region indicator (IRI) analyses were calculated to show relative chemical bond changes before and after coordination. [ABSTRACT FROM AUTHOR]

By the interaction of [Rh2(COE)4(μ-Cl)2] (COE = cyclooctene) with 1,2-bis[(2,6-diisopropyl phenyl)imino]acenaphthene (dpp-bian) new binuclear complex [Rh2(dpp-bian)2(μ-Cl)2]·2.72CH2Cl2 is obtained. The crystal structure is determined by the single crystal X-ray diffraction analysis. Compound 1·2.72CH2Cl2 crystallizes in the orthorhombic crystal system (space group Pnma) with unit cell parameters a = 51.200(3) Å, b = 22.3795(13) Å, c = 12.8631(8) Å, V = 14739.0(16) Å3, R = 0.0536. Each rhodium atom has a distorted square-planar environment formed by two dpp-bian N atoms and two bridging Cl atoms. Density functional theory calculations predict the existence of two isomers of the [Rh2(dpp-bian)2(μ-Cl)2] complex with similar formation energies. [ABSTRACT FROM AUTHOR]

In this work, methyl(tert-butoxycarbonyl)-L-tyrosinate and methyl(2,2,2-trifluoroacetyl)-L-tyrosinate are synthesized, and their structures are confirmed spectroscopically. Single crystals of these compounds are studied by X-ray diffraction. The optimized molecular structure is determined by density functional theory (DFT) calculations using the B3LYP/6-311G(2d,p) basis set, and the structure is compared with the X-ray structure. Conformational analyses reveal that the experimentally obtained and theoretically predicted structures are consistent with each other. In addition, molecular electrostatic potentials and frontier molecular orbitals of the two compounds are studied by DFT to reveal certain physicochemical properties of the compounds. [ABSTRACT FROM AUTHOR]

N-(2-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-3-methyl-butanamide is an important boric acid derivative. In this article, the title compound is obtained by a two-step substitution reaction. The structure of the title compound is verified by FTIR, 1H and 13C NMR, and MS. Simultaneously, the single crystal structure of the title compound is gauged by X-ray diffraction and subjected to crystallographic and conformational analyses. Density functional theory (DFT) is applied to further calculate the molecular structure and compare it with X-ray values. The result of the conformational analysis shows that the molecular structure optimized by DFT is identical with the single crystal structure determined by single crystal X-ray diffraction. In addition, DFT is used to further study the molecular electrostatic potential and frontier molecular orbitals of the title compound, revealing the molecular structure characteristics, conformation, and some special physical and chemical properties of the title compound. [ABSTRACT FROM AUTHOR]

A new pyrido[2,3-d]pyrimidine derivative 1-(3-((6-bromopyrido[2,3-d]pyrimidin-4-yl)oxy)phenyl)-3-cyclopentylurea is designed and synthesized. The final structure is characterized by 1H, 13C, and 2D NMR, MS, FTIR. In addition, the crystal structure of the title compound is determined by X-ray diffraction. With the 6-311G(2d,p) basis set, the molecule is further explored using density functional theory (DFT) by the B3LYP method. The final results show that the DFT optimized structure of the title molecule is consistent with the crystal structure determined by X-ray diffraction. The Hirshfeld surface analysis and the 2D fingerprint plot are given to support the quantitative analysis of intermolecular interactions and contacts generated by supramolecular accumulation in crystals. The interactions of the title molecule are analyzed by the natural bond orbital analysis. Finally, the molecular electrostatic potential and frontier molecular orbitals are further investigated using DFT. [ABSTRACT FROM AUTHOR]

In this paper, the triazoloquinazolinone derivative 1-(pyrrolidin-1-yl-methyl)-4-(thiophen-2-yl-methyl)[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-one is synthesized and characterized by spectroscopy. The density functional theory (DFT) is used to calculate the optimal structure of the title compound using the B3LYP correlation function with the 6-311G(2d,p) basis set. Furthermore, the crystal structure of the title compound is determined by the X-ray diffraction analysis, and its geometric data are very close to the DFT calculated results for the optimized structure. In addition, the antitumor activity of the title compound on A375 cells is studied using SHP244 and Sorafenib as positive control drugs. The results show that the inhibitory rates of the title compound, SHP244, and Sorafenib on A375 cells are 12.10%, 13.84%, and 14.82%, respectively. [ABSTRACT FROM AUTHOR]

Arylsulfochlorination of β-aminopropioamidoximes is theoretically studied using estimations of thermodynamic parameters of the corresponding reactions, quantum chemical HOMO–LUMO analysis of molecular structures of reaction products. Full geometry optimization of the molecules is performed and vibrational frequencies are calculated with the Gaussian09 program using the DFT method at the B3LYP/6-31++G(d,p) level of theory. It is established that para-toluenesulfonates and para-nitrobenzenesulfonates of spiropyrazolinium compounds are thermodynamically most preferable in the arylsulfochlorination reactions of four studied β-aminopropioamidoximes in the presence of DIPEA, while the O-substitution products are most preferable in the reaction of β-(benzimidazol-1-yl)propioamidoxime arylsulfochlorination. The calculated results agree with experimental data and can be used to predict the structure and properties of amidoxime arylsulfochlorination products. [ABSTRACT FROM AUTHOR]

Electronic structure and interactions between central atoms C and Ge and ethynyl groups in C(C≡CH)4 and Ge(C≡CH)4 are studied by the density functional theory; the experimental X-ray photoelectron spectroscopy data are obtained. Using calculations, correlation diagrams of energy levels for C(C≡CH)4, Ge(C≡CH)4, and C2H2 are constructed and compared with each other. Densities of states of C and Ge atoms in the molecules are analyzed. The main types of interatomic electronic interactions resulting in chemical bonds between central atoms C and Ge and ethynyl groups are determined from theoretical and experimental data. [ABSTRACT FROM AUTHOR]

N-(2-methoxy-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-3-yl)cyclopropanesulfonamide is an organic intermediate with borate and sulfonamide groups, which can be synthesized through nucleophilic and amidation reactions. In this article, we characterize the structure of the title compound by 1H and 13C NMR, IR, MS, and single crystal X-ray diffraction of the title compound for crystallographic and conformational analyses. The comparison of the actual value with the value calculated by density functional theory (DFT) shows that the crystal structures obtained by the two methods are consistent. On this basis, DFT is used to study the molecular electrostatic potential and frontier molecular orbitals of the title compound to further clarify certain physical and chemical properties of the compound. [ABSTRACT FROM AUTHOR]

4-(2-Chlorobenzyl)-1-(5-nitro-2-(pyrrolidin-1-yl)phenyl)-[1,2,4]triazolo[4,3-a]quinazo-lin-5(4H)-one is a derivative of quinazolinones with antitumor, antibacterial, anti-inflammatory, and antimicrobial effects. Using diabetic jujube as a raw material, the title compound is synthesized by substitution and cyclization steps. The structure of the target compound is confirmed by FTIR, 1H and 13C NMR, and MS spectroscopies. The precise structure of the 4-(2-chlorobenzyl)-1-(5-nitro-2-(pyrrolidin-1-yl)phenyl)-[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-one compound is analyzed by single crystal X-ray diffraction (XRD). The molecular structure is further calculated using density functional theory (DFT) and the result is compared with the XRD value. The molecular electrostatic potential and frontier molecular orbitals of the title compound are investigated using DFT. In addition, the obtained atomic coordinates for the single crystal of the compound are then applied in a molecular docking simulation, and the title compound is found to participate in a number of important binding interactions in the SHP2 binding sites. [ABSTRACT FROM AUTHOR]

Structure, energy and spectral parameters of moieties of C3H7OH–HCl solutions with various compositions are calculated using density functional theory based on the regularities characterizing formation of complexes with hydrogen bonds in binary systems. It is shown that six concentration structural zones can be distinguished in the C3H7OH–HCl system (1:0-6:5). Liquid isopropyl alcohol consists of cyclic hexamers (C3H7OH)6. Solutions of each of the five subsequent zones contain two types of cyclic moieties whose average H-bond energies (~30-74 kcal/mol) are 5-10 times larger than those in hexamer (C3H7OH)6. The main interactions between components in the C3H7OH–HCl system occur inside such moieties (almost completely isolated from each other by alkyl groups of C3H7OH molecules). Such moieties contain previously unknown complexes with two quasi-symmetric bridges Cl⋯H⋯O and O⋯H⋯O, conjugated proton solvates, having one common oxygen atom. The concentrated solutions contain, in addition to conjugated proton solvates, moieties with the composition 2:2, each having four Cl⋯H⋯O bridges with similar parameters. The fact that the maximum density of these solutions and the HCl solubility limit approximately correspond to the component mole ratio 6:5 was explained and all features of obtained IR spectra were interpreted by using calculated data on the structure of C3H7OH–HCl solutions and that of observed complexes. [ABSTRACT FROM AUTHOR]

Tert-butyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indazole-1-carboxylate is a significant intermediate of 1H-indazole derivatives. In this paper, the title compound is acquired through two substitution reactions. The structure is corroborated by FTIR, 1H and 13C NMR spectroscopy, and MS. In the meantime, the single crystal is detected by means of X-ray diffraction, calculated by exerting density functional theory (DFT), and subjected to the crystallographic and conformational analysis. The results of comparing the DFT calculated value with the X-ray diffraction value display that the optimized molecular structure does cohere with the single crystal structure ascertained via the experiment. The 98.28% stable conformer and 1.72% unstable conformers are found in the DFT calculations. Furthermore, to reveal the physicochemical features of the title compound, the molecular electrostatic potential and frontier molecular orbitals are investigated through DFT. [ABSTRACT FROM AUTHOR]

Short supramolecular Br···Br and I···I contacts in chalcogenides Ti4Se9I6, V4S9Br4, Ta4S9Br8, and Ta4Se9I8 with a square {M4Q9} core are theoretically studied by quantum chemical calculations within the density functional theory (ωB97XD/DZP-DKH) and the QTAIM topological analysis of the electron density distribution. [ABSTRACT FROM AUTHOR]

The structure and metal complexation studies using dispersion-corrected density functional theory methods are performed for four stable glycolic acid conformers named SSC, GAC, SAC, and AAT. The condensed Fukui functions are calculated to study the favourable reactive site for metal binding on the glycolic acid conformers. The interaction of alkali metal ions (Na+, K+) with different binding sites (carboxyl, hydroxyl oxygen) of the glycolic acid conformers in the gas phase is investigated at the same level of theory. Our calculations show that the order of stability changes into SSC > AAT > GAC = SAC due to the binding of the metal ion. The relative energy values indicate that the AAT conformer is more stable than the GAC and SAC conformers. This occurs when a metal ion (Na+, K+) is bound with the carboxyl oxygen atom of glycolic acid. The QTAIM, RDG, NCI, ELF, LOL, and NBO analysis are employed in this work to understand the strength of intra- and intermolecular interactions in the glycolic acid metal complexes. [ABSTRACT FROM AUTHOR]

Sulfonamides are used as antibacterial drugs for decades. 3-bromo-N-(3-fluorophenyl) benzenesulfonamide is synthesized by the amidation reaction. The structure of the title compound is confirmed by FTIR, 1H and 13C NMR, and MS spectroscopies. At the same time, the single crystal of the compound is analyzed by X-ray diffraction and the conformational analysis is performed. Density functional theory (DFT) is used to further calculate the molecular structure, and the results are consistent with the X-ray diffraction results. In addition, DFT is also used to calculate and analyze the electrostatic potential and the frontier molecular orbital of the molecule, which provides some references for the analysis of the physical and chemical properties of the molecule. In addition, vibrational frequencies are analyzed, revealing some physicochemical properties of the title compound. [ABSTRACT FROM AUTHOR]

The clusters InxO (x = 2, 3) and In4O0/—1 arestudied using density functional theory (B3PW91). The global minima contain linear di-coordinated, T-shape tri-coordinated, and planar tetra-coordinated oxygen atoms for In2O, In3O, and In4O, respectively. 18-valence electrons contribute to square structure of In4O. Excitingly, 19-valence electron in [In4O]– contains tetra-coordinated oxygen. Molecular orbitals analysis reveals that delocalized π-bonding and σ-bonding orbitals stabilize the planar tetra-coordinated bonding of oxygen. In addition, the stability becomes worse with a decrease in coordination number. [ABSTRACT FROM AUTHOR]