Mulliken Population Method Research Articles

The interfacial properties and fracture behavior of the graphite (0001)/Cu (111) interface from a first–principles investigation

Interface considerably influences the properties of copper (Cu)–graphite composites. Therefore, considerable understanding of the interface is required to improve the mechanical and tribological properties of these composites. Because the graphite (0001) and Cu (111) interfaces are a good match, this study focuses on calculating the related properties of the interface structure using first–principles calculations. The parameter setting of this work is reasonable when comparing the theoretical and experimental results of the bulk Cu and graphite. Slabs of the nine-layer graphite (0001) and seven-layer Cu (111) surfaces have excellent convergence. The order of interfacial configuration stability is [Formula: see text] and HCP possesses the largest work of adhesion and smallest interface energy among the studied interface structures. Furthermore, the electron density and Mulliken population method are used to examine the interfacial bonds.

Structural and electronic properties of chromium carbides and Fe-substituted chromium carbides

Chromium carbides are coated over base metal (Fe) to increase wear and corrosion resistance. The electronic structure and bonding properties for chromium carbide bulk phases (Cr3C2, Cr7C3 and Cr23C6) and Fe-substituted chromium carbides is investigated using Density Functional Theory (DFT). The bonding in these carbides has been interpreted in the form of partial density of states, electron density distribution and Mulliken population method. Cr3C2 exhibits the strongest covalent character while Cr7C3 displays the highest metallicity. Cr3C2 showed the highest stability among the chromium carbide phases. In the Fe-substituted chromium carbides (Cr2FeC2), the site preference of Fe in Cr3C2 system has been reported. In Fe-substituted chromium carbides also show both of metallic and covalent character and Cr2Fe3C2 is found to be the most stable Fe-substituted chromium carbide system.

Synthesis, crystallographic structure, theoretical calculations, spectral and thermal properties of trans-diaquabis(trans-4-aminoantipyrine)cobalt(II) acesulfamate

A new acesulfame derivative compound, trans-diaquabis(trans-4-aminoantipyrine)cobalt(II) acesulfamate that formulated as (C30H38CoN8O12S2) was synthesized and characterized by X-ray diffraction method, FT-IR, UV–Vis techniques and Thermal analysis. The compound crystallizes in the orthorhombic space group Pbcn with parameters a = 28.0156 (10) Å, b = 9.4273 (4) Å, c = 13.7777 (5) Å, α = β = γ = 90°, Z = 4. Theoretical calculations have been carried out by using Density Functional Theory (DFT) method in the ground state. With a successful optimization, Mulliken population method, molecular electrostatic potential (MEP) and frontier molecular orbitals were calculated. In addition, the thermal behavior of the complex was investigated. Hirshfeld surface analyses (dnorm surfaces and two-dimensional fingerprint plots) which reveal the nature of intermolecular interactions for the title compound were performed and discussed. The Hirshfeld surface analysis of the crystal structure specifies that the most important contributions for the crystal packing are from O⋯H/H⋯O (37.1%), H⋯H (33.5%) and C⋯H/H⋯C (16.5%) interactions.

X-ray and DFT Investigation of (E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol Compound

(E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol was investigated by experimental and theoretical methodologies. The solid state molecular structure was determined by X-ray diffraction method. All theoretical calculations were performed by density functional theory (DFT) method by using B3LYP/6-31G(d,p) basis set. The titled compound showed the preference of enol form, as supported by X-ray diffraction method. The geometric and molecular properties were compaired for both enol-imine and keto-amine forms for title compound. Stability of the molecule arises from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed using natural bond orbital (NBO) analysis. Mulliken population method and natural population analysis (NPA) have been studied. Also, condensed Fukui function and relative nucleophilicity indices calculated from charges obtained with orbital charge calculation methods (NPA). Molecular electrostatic potential (MEP) and non linear optical (NLO) properties are also examined.

XRD, FT–IR and UV characterization, hirshfeld surface analysis and local-global chemical descriptor studies of (E)-2-((3-fluorophenylimino)methyl)-3-methoxyphenol (1) and (E)-2-((2-fluorophenylimino)methyl)-3-methoxyphenol (2)

A series of novel (E)-2-((3-fluorophenylimino)methyl)-3-methoxyphenol (1) and (E)-2-((2-fluorophenylimino)methyl)-3-methoxyphenol (2) were synthesized and characterized by X-ray diffraction method, FT–IR and UV–Vis techniques. The experimental FI-IR and UV–Vis spectra showed that 1 and 2 were formed single crystal and displayed enol-imine form. Hirshfeld surface analysis was carried out for title molecules, which reveals the nature of intermolecular contacts, the fingerprint plots and molecular surface contours (dnorm, di and de). The optimized molecular geometry (bond length, bond angle, torsion angle) and all other theoretical computations were calculated by using density functional theory (DFT) B3LYP method with the help of 6-31G (d,p) basis set. The optimized geometry results, which were well represented by the X-ray data, show that DFT/B3LYP 6-31G (d,p) was a suitable level of theory. After a successful optimization, frontier molecular orbitals, chemical activity, non-linear optical properties (NLO), natural bond orbital (NBO) analysis, molecular electrostatic potential (MEP), fukui function analysis, Mulliken population method (MPA) and natural population analysis (NPA), which cannot be obtained experimentally, were calculated and investigated.

Synthesis, X-ray diffraction method, spectroscopic characterization (FT-IR, 1H and 13C NMR), antimicrobial activity, Hirshfeld surface analysis and DFT computations of novel sulfonamide derivatives

Synthesized compounds of N-(2-aminophenyl)benzenesulfonamide 1 and (Z)-N-(2-((2-nitrobenzylidene)amino)phenyl)benzenesulfonamide 2 were characterized by antimicrobial activity, FT-IR, 1H and 13C NMR. Two new Schiff base ligands containing aromatic sulfonamide fragment of (Z)-N-(2-((3-nitrobenzylidene)amino)phenyl)benzenesulfonamide 3 and (Z)-N-(2-((4-nitrobenzylidene)amino)phenyl)benzenesulfonamide 4 were synthesized and investigated by spectroscopic techniques including 1H and 13C NMR, FT-IR, single crystal X-ray diffraction, Hirshfeld surface, theoretical method analyses and by antimicrobial activity. The molecular geometry obtained from the X-ray structure determination was optimized Density Functional Theory (DFT/B3LYP) method with the 6–311++G(d,p) basis set in ground state. From the optimized geometry of the molecules of 3 and 4, the geometric parameters, vibrational wavenumbers and chemical shifts were computed. The optimized geometry results, which were well represented the X-ray data, were shown that the chosen of DFT/B3LYP 6-311G++(d,p) was a successful choice. After a successful optimization, frontier molecular orbitals, chemical activity, non-linear optical properties (NLO), molecular electrostatic mep (MEP), Mulliken population method, natural population analysis (NPA) and natural bond orbital analysis (NBO), which cannot be obtained experimentally, were calculated and investigated.

X-ray structural, spectroscopic and computational approach (NBO, MEP, NLO, NPA, fukui function analyses) of (E)-2-((4-bromophenylimino)methyl)-3-methoxyphenol

ABSTRACTThe title compound was isolated and investigated by experimental X-ray diffraction method and density functional theory (DFT) calculational properties and spectroscopic methodologies. The experimental investigations of the compound indicated the molecule seems to be in enol form. DFT calculations are performed both for enol and keto tautomers of the title compound. Additionally chemical activity, electronic transmission and property effect on different solvents, molecular electrostatic potential (MEP), non-linear optical properties (NLO), Mulliken population method, natural population analysis (NPA), natural bond orbital (NBO) and Fukui function analyses have been studied.

Synthesis, molecular structure, vibrational spectroscopy, optical investigation and DFT study of a novel hybrid material: 3,3′-diammoniumdiphenylsulfone hexachloridostannate monohydrate

In his work we investigate a new halogenotin (IV) organic inorganic material. The structure, determined by single-crystal X-ray diffraction at 293 K of 3,3′-diammoniumdiphenylsulfone hexachloridostannate monohydrate abbreviated 3,3′(DDS)SnCl6, can be viewed as inorganic layers built from (SnCl6)2− octahedra and H2O molecules, between which, the organic entities [C12H14N2O2S]2+ are inserted. Experimental room-temperature X-ray studies were supported by theoretical methods using density functional theory (DFT). The detailed examination of the vibrational spectra of our material was correlated by DFT calculation using the unit cell parameters obtained from the experiment data.The optical properties in the UV–visible region have been explored by the UV–visible absorption. This material shows a single absorption band centred at 325 nm (318 eV). The energy difference between Occupied, HOMO and Lowest Unoccupied, LUMO orbital which is called energy gap can be used to predict the strength and stability of metal complexes, as well as in determining molecular electrical transport properties. For the calculation of excitation energies in the optical studies we used Time-Dependent Density Functional Theory (TD-DFT). In addition, Mulliken population method and molecular electrostatic potential (MEP) of the title material have been theoretically studied by GAUSSIAN 03 package.

Crystallographic, spectroscopic (FTIR and NMR) and quantum computational calculation studies on bis(2-methoxy-4-((E)-prop-1-enyl)phenyl)oxalate

In this paper, we report first, a new synthesis of bis(2-methoxy-4-((E)-prop-1-enyl)phenyl)oxalate, namely, C22H22O6, (I). Then, we present detailed FTIR, 1H NMR, 13C NMR spectroscopies and single-crystal X-ray diffraction techniques, Hartree-Fock (HF) and Density Functional Theory (DFT) molecular orbital calculation study of the title compound. Compound (I) crystallizes in the monoclinic space group P21/c, with Z = 2 in cells with a = 6.3440(5)Å, b = 10.1098(9)Å, c = 16.1899(15)Å, V = 1035.65(16)Å3 and displays weak C-H⋯O intermolecular interaction which contributes to crystal packing. The molecular geometry was also calculated using the Gaussian03W software, and structure was optimized using the HF and DFT/B3LYP methods with the 6-31G(d,p) basis set at the ground state. The harmonic vibrational frequencies, 1H and 13C NMR chemical shifts of I were calculated using the same method with the 6-31G(d,p) basis set. The calculated results show that the predicted geometry can well reproduce structural parameters. The energetic behaviors of the title compound in solvent media were examined using the DFT/B3LYP method with the 6-31G(d,p) basis set applying the Polarizable Continuum Model (PCM). Besides, the frontier molecular orbitals (FMOs), Mulliken population method, natural population analysis (NPA), molecular electrostatic potential (MEP) map of the title compound were investigated by theoretical calculations. Based on vibrational analyses, the thermodynamic properties of I at different temperatures have been calculated, and corresponding relations between the properties and temperature have also been obtained.

Theoretical and experimental investigations on molecular structure of bis(2-methoxy-4-allylphenyl)oxalate

The aim of this study is to find out the molecular characteristic and structural parameters that govern the chemical behavior of a new bis(2-methoxy-4-allylphenyl)oxalate compound and to compare predictions made from theory with experimental observations. The title compound, bis(2-methoxy-4-allylphenyl)oxalate (I), (C22H22O6), has been synthesized. The compound has been characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopies and single crystal X-ray diffraction techniques. Optimized molecular structure, harmonic vibrational frequencies have been calculated by B3LYP/6-311G(d,p) method using density functional theory (DFT). 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule have been investigated by the Gauge-Invariant Atomic Orbital (GIAO) method. The calculated results show that the predicted geometry can well reproduce structural parameters. To estimate chemical reactive sites of the molecule, molecular electrostatic potential map (MEP), frontier molecular orbitals (FMOs), Mulliken population method and natural population analysis (NPA) have been calculated for the optimized geometry of the molecule. To investigate the NLO properties of the molecule, the electric dipole, the polarizability and the first hyperpolarizability have been calculated. In addition, thermodynamic properties have also been studied.

Theoretical analysis (NBO, NPA, Mulliken population method) and molecular orbital studies (hardness, chemical potential, electrophilicity and Fukui function analysis) of (E)-2-[(4-hydroxy-2-methylphenylimino)methyl]-3-methoxyphenol

Theoretical analysis (NBO, NPA, Mulliken population method) and molecular orbital studies (hardness, chemical potential, electrophilicity and Fukui function analysis) of (<i>E</i>)-2-[(4-hydroxy-2-methylphenylimino)methyl]-3-methoxyphenol

Theoretical analysis (NBO, NPA, Mulliken Population Method) and molecular orbital studies (hardness, chemical potential, electrophilicity and Fukui function analysis) of (E)-2-((4-hydroxy-2-methylphenylimino)methyl)-3-methoxyphenol

The molecular structure and spectroscopic properties of (E)-2-((4-hydroxy-2-methylphenylimino)methyl)-3-methoxyphenol, were characterized by X-ray diffraction, FT-IR and UV–Vis spectroscopy. All of theoretical calculations and optimized geometric parameters have been calculated by using density functional theory (DFT) with hybrid method B3LYP by 6-31G(d,p) basis set. The title compound of C15H15N1O3 have been analyzed according to electronic and energetics behaviors for enol-imine and keto-amine tautomers. Both these tautomers engender six-membered ring due to intramolecular hydrogen bonded interactions. Two types of intramolecular hydrogen bonds (a) strong O–H⋯N interactions in enol-imine form and (b) N–H⋯O interactions in keto-amine form are compared particularly. The theoretical vibrational frequencies have been found in good agreement with the corresponding experimental data. A study on the electronic and optical properties, absorption wavelengths, excitation energy, dipole moment, molecular electrostatic potential (MEP) and frontier molecular orbital energies are performed using DFT method. Additionally, geometry optimizations in solvent media were performed with the same level of theory by the polarizable continuum model (PCM). The effect of solvents on the tautomeric stability has been investigated. Mulliken Population Method and natural population analysis (NPA) have been studied. NBO analysis is carried out to picture the charge transfer between the localized bonds and lone pairs. The local reactivity of the molecule has been studied using the Fukui function. NLO properties related to polarizability and hyperpolarizability are also discussed.

Synthesis, molecular structure, spectroscopic analysis, thermodynamic parameters and molecular modeling studies of (2-methoxyphenyl)oxalate

The aim of this study is to find out the molecular characteristic and structural parameters that govern the chemical behavior of a new (2-methoxyphenyl)oxalate compound and to compare predictions made from theory with experimental observations. The title compound, (2-methoxyphenyl)oxalate, (I), (C16H14O6), has been synthesized. The compound has been characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopies and single crystal X-ray diffraction techniques. Optimized molecular structure, harmonic vibrational frequencies, 1H and 13C NMR chemical shifts have been investigated by B3LYP/6-31G(d,p) method using density functional theory (DFT). The calculated results show that the predicted geometry can well reproduce structural parameters. In addition, global chemical reactivity descriptors, molecular electrostatic potential map (MEP), frontier molecular orbitals (FMOs), Mulliken population method and natural population analysis (NPA) and thermodynamic properties have also been studied. The energetic behavior of title compound has been examined in solvent media using polarizable continuum model (PCM).

The spectroscopic (FT-IR, UV–vis), Fukui function, NLO, NBO, NPA and tautomerism effect analysis of (E)-2-[(2-hydroxy-6-methoxybenzylidene)amino]benzonitrile

A new o-hydroxy Schiff base, (E)-2-[(2-hydroxy-6-methoxybenzylidene)amino]benzonitrile was isolated and investigated by experimental and theoretical methodologies. The solid state molecular structure was determined by X-ray diffraction method. The vibrational spectral analysis was carried out by using FT-IR spectroscopy in the range of 4000–400cm−1. Theoretical calculations were performed by density functional theory (DFT) method using 6-31G(d,p) basis set. The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The UV–vis spectrum of the compound was recorded in the region 200–800nm in several solvents and electronic properties such as excitation energies, and wavelengths were calculated by TD-DFT/B3LYP method. The most prominent transitions were corresponds to π→π∗.Hybrid density functional theory (DFT) was used to investigate the enol-imine and keto-amine tautomers of titled compound. The titled compound showed the preference of enol form, as supported by X-ray and spectroscopic analysis results. The geometric and molecular properties were compaired for both enol-imine and keto-amine forms. Additionally, geometry optimizations in solvent media were performed with the same level of theory by the integral equation formalism polarizable continuum (IEF-PCM). Stability of the molecule arises from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed using natural bond orbital (NBO) analysis. Mulliken population method and natural population analysis (NPA) have been studied. Also, condensed Fukui function and relative nucleophilicity indices calculated from charges obtained with orbital charge calculation methods (NPA). Molecular electrostatic potential (MEP) and non linear optical (NLO) properties are also examined.

Experimental (X-ray, FT-IR and UV–vis spectra) and theoretical methods (DFT study) of (E)-3-methoxy-2-[(p-tolylimino)methyl]phenol

A suitable single crystal of (E)-3-methoxy-2-[(p-tolylimino)methyl]phenol, formulated as C15H15N1O2, reveals that the structure is adopted to its E configuration about the azomethine CN double bond. The compound adopts a enol–imine tautomeric form with a strong intramolecular OH⋯N hydrogen bond. The single crystal X-ray diffraction analysis at 296K crystallizes in the monoclinic space group P21/c with a=13.4791(11) Å, b=6.8251(3) Å, c=18.3561(15) Å, α=90°, β=129.296(5)°, γ=90° and Z=4. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR and UV–vis spectrometry.Optimized molecular structure and harmonic vibrational frequencies have been investigated by DFT/B3LYP method with 6-31G(d,p) basis set. Stability of the molecule, hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed by using natural bond orbital (NBO) analysis.Electronic structures were discussed by TD-DFT method and the relocation of the electron density were determined. The energetic behavior of the title compound has been examined in solvent media using polarizable continuum model (PCM). Molecular electrostatic potential (MEP), Mulliken population method and natural population analysis (NPA) have been studied. Nonlinear optical (NLO) properties were also investigated. In addition, frontier molecular orbitals analysis have been performed from the optimized geometry. An ionization potential (I), electron affinity (A), electrophilicity index (ω), chemical potential (μ), electronegativity (χ), hardness (η), and softness (S), have been investigated.

Theoretical and experimental investigation of (E)-2-([3,4-dimethylphenyl)imino]methyl)-3-methoxyphenol: Enol–keto tautomerism, spectroscopic properties, NLO, NBO and NPA analysis

The molecular structure and spectroscopic properties of (E)-2-([3,4-dimethylphenyl)imino]methyl)-3-methoxyphenol were investigated by X-ray diffraction, FT-IR and UV–vis spectroscopy. The vibrational frequencies calculatedusing DFT/B3LYP/6-31G(d,p) method. Results showed better agreement with the experimental values. The electronic properties was studied and the most prominent transition corresponds to π→π* and n→π*. Two types of intramolecular hydrogen bonds are strong OH⋯N interactions in enol-imine form and NH⋯O interactions in keto-amine form are compared by using density functional theory (DFT) method with B3LYP applying 6-31G(d,p) basis set. Both enol–keto tautomers engender six-membered ring due to intramolecular hydrogen bonded interactions.Geometry optimizations in solvent media were performed with the same level of theory by the polarizable continuum model (PCM). The effect of solvents on the tautomeric stability has been investigated. Stability of the molecule arises from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed using natural bond orbital (NBO) analysis. Molecular electrostatic potential (MEP) of the titled compound was studied for predicting the reactive sites. Mulliken population method and natural population analysis (NPA) have been studied. Population methods and MEP generally provides information regarding the chemical reactivity regions and charge distributions. Additionally, Frontier Molecular Orbitals analysis hasbeen performed from the optimized geometry. These orbitals also related to ionization potential, electron affinity, kinetic stability and hyperpolarizability of the molecule. The molecule exhibited good nonlinear optical (NLO) activity and first order hyperpolarizability. The predicted nonlinear optical properties of the title compound are 18 times greater than ones of urea.

Structures and stabilities of AunXm(n+m=4，X=Cu, Al, Y) clusters

The equilibrium geometries and electronic structure properties of mixed Aun Xm(n+m=4, X=Cu, Al, Y) have been obtained by using the B3LYP hybrid wh ich is based on non-local density functional theory method. The binding energies, ionization potential, electron affinity, the highest occupied molecular orbital ener gy level, lowest unoccupied molecular orbital energy level,and the energy gaps o f them have been calculated. By analyzing the properties of electrons using the Mulliken population method, it is concluded that impurity increases the stabilit ies of Au cluster. When Cu, Al and Y doped in Au4 cluster, the energy gaps reduce and the binding energies increase.

A Theoretical Study of the Protonation of Purine

AbstractEnergy profiles and molecular binding number (MBN) were calculated for purine and its mono‐protonated forms by the CNDO/2 algorithm. Total energy indicates that the 3,7‐species is the most stable among the protonated isomers, being insignificantly more stable than the 1,7‐analogue. Electronic energy suggests that proton may preferentially be attached to position 3. Charge densities are presented by both Mulliken's population method and CNDO/2.