Guest–Host Interaction of Coinage Metals in π-Rich Cavities

2016 ◽  
Vol 69 (9) ◽  
pp. 969 ◽  
Author(s):  
Zhi Xiang Wong ◽  
Matthias Lein
Keyword(s):  
Density Functional ◽  
Copper Ions ◽  
Silver Ions ◽  
Intermolecular Forces ◽  
Orbital Energy ◽  
Hybrid Functional ◽  
Coinage Metal ◽  
Host Interaction ◽  
Coinage Metals ◽  
Weak Intermolecular Forces

The complexation of coinage metal cations with [2.2.2]paracyclophane and deltaphane has been investigated by means of density functional theory (DFT) calculations employing the PBE0-D3 hybrid functional, which incorporates explicit dispersion corrections to account for the weak intermolecular forces that are important in the systems studied. Natural bond orbital (NBO) analyses, Bader's Atoms in Molecules theory analyses as well as localised molecular orbital – energy decomposition analyses (LMO-EDAs) have been carried out to further investigate the electronic structure and bonding of the complexes. It was found that both cyclophanes bind strongest with gold ions, followed closely by copper ions and lastly silver ions. The two fragments interact in a non-covalent fashion in these complexes and the metal preferentially resides at the periphery of the molecular cavity of the cyclophane.

On the Nature of Halide-Water Interactions: Insights from Many-Body Representations and Density Functional Theory

2019 ◽  
Author(s):  
Brandon B. Bizzarro ◽  
Colin K. Egan ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Orbital Energy ◽  
Energy Decomposition Analysis ◽  
Interaction Energies ◽  
Many Body ◽  
Functional Theory

<div> <div> <div> <p>Interaction energies of halide-water dimers, X<sup>-</sup>(H<sub>2</sub>O), and trimers, X<sup>-</sup>(H<sub>2</sub>O)<sub>2</sub>, with X = F, Cl, Br, and I, are investigated using various many-body models and exchange-correlation functionals selected across the hierarchy of density functional theory (DFT) approximations. Analysis of the results obtained with the many-body models demonstrates the need to capture important short-range interactions in the regime of large inter-molecular orbital overlap, such as charge transfer and charge penetration. Failure to reproduce these effects can lead to large deviations relative to reference data calculated at the coupled cluster level of theory. Decompositions of interaction energies carried out with the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method demonstrate that permanent and inductive electrostatic energies are accurately reproduced by all classes of XC functionals (from generalized gradient corrected (GGA) to hybrid and range-separated functionals), while significant variance is found for charge transfer energies predicted by different XC functionals. Since GGA and hybrid XC functionals predict the most and least attractive charge transfer energies, respectively, the large variance is likely due to the delocalization error. In this scenario, the hybrid XC functionals are then expected to provide the most accurate charge transfer energies. The sum of Pauli repulsion and dispersion energies are the most varied among the XC functionals, but it is found that a correspondence between the interaction energy and the ALMO EDA total frozen energy may be used to determine accurate estimates for these contributions. </p> </div> </div> </div>

Spectroscopic investigations and DFT studies of synthesized 4-acetamidophenyl 3,4,5-trimethoxybenzoate and 4-acetyl phenyl 3,4,5-trimethoxybenzoate a novel conjugate of gallic acid

2020 ◽  
Vol 17 ◽  
Author(s):  
Sangeeta Srivastava ◽  
Nadeem Ahmad Ansari ◽  
Sadaf Aleem
Keyword(s):  
Gallic Acid ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Major Constituent ◽  
Orbital Energy ◽  
Reactivity Descriptors ◽  
Homo And Lumo ◽  
Electrophilic Reactivity ◽  
Global And Local

: Gallic acid is abundantly found in amla (Phyllanthus emblica), a deciduous of the family phyllanthaceae. Gallic acid, the major constituent of the plant was methylated to 3,4,5 trimethoxy gallic acid, which then underwent steglich esterification first with paracetamol and then with 4-hydroxy acetophenone to yield 4-acetamidophenyl 3,4,5-trimethoxybenzoate and 4-acetyl phenyl 3,4,5-trimethoxybenzoate “respectively”. 1H NMR, 13C NMR, UV, FT-IR and mass spectroscopy were used to characterize the synthesized compounds. Density functional theory (B3YLP) using 6-31G (d,p) basis set have been used for quantum chemical calculations. AIM (Atom in molecule) approach depicted weak molecular interactions within the molecules whereas the reactive site and reactivity within the molecule were examined by global and local reactivity descriptors. The HOMO and LUMO energies and frontier orbital energy gap were calculated by time dependant DFT approach using IEFPCM model. Small value for HOMO–LUMO energy gap indicated that easier charge transfer occurs within compound 4. The nucleophilic and electrophilic reactivity were determined by MEP (molecular electrostatic potential) experiment. Polarizability, dipole moment, and first hyperpolarizability values were calculated to depict the NLO (nonlinear optical) property of both the synthesized compounds. The antimicrobial activity was also carried out and broad spectrum antibacterial activity against several strains of bacteria and certain unicellular fungi were exhibited by synthesized compound 3.

scholarly journals A New Piano-Stool Ruthenium(II) P-Cymene-Based Complex: Crystallographic, Hirshfeld Surface, DFT, and Luminescent Studies

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 13
Author(s):  
Mohd. Muddassir ◽  
Abdullah Alarifi ◽  
Mohd. Afzal
Keyword(s):  
Density Functional ◽  
Weak Interactions ◽  
Energy Levels ◽  
Hirshfeld Surface ◽  
Binding Energies ◽  
Orbital Energy ◽  
Aminosalicylic Acid ◽  
Full Characterization

A new complex (Ru(η6-p-cymene)(5-ASA)Cl2) (1) where 5-ASA is 5-aminosalicylic acid has been prepared by reacting the ruthenium arene precursors ((η6-arene)Ru(μ-Cl)Cl)2, with the 5-ASA ligands in a 1:1 ratio. Full characterization of complex 1 was accomplished by elemental analysis, IR, and TGA following the structure obtained from a single-crystal X-ray pattern. The structural analysis revealed that complex 1 shows a “piano-stool” geometry with Ru-C (2.160(5)- 2.208(5)Å), Ru-N (2.159(4) Å) distances, which is similar to equivalents sister complex. Density functional theory (DFT) was used to calculate the significant molecular orbital energy levels, binding energies, bond angles, bond lengths, and spectral data (FTIR, NMR, and UV–VIS) of complex 1, consistent with the experimental results. The IR and UV–VIS spectra of complex 1 were computed using all of the methods and choose the most appropriate way to discuss. Hirshfeld surface analysis was also executed to understand the role of weak interactions such as H⋯H, C⋯H, C-H⋯π, and vdW interactions, which play a significant role in the crystal environment’s stability. Moreover, the luminescence results at room temperature show that complex 1 gives a more intense emission band positioned at 465 nm upon excitation at 330 nm makes it a suitable candidate for the building of photoluminescent material.

scholarly journals Intercalated architecture of MA2Z4 family layered van der Waals materials with emerging topological, magnetic and superconducting properties

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Wang ◽  
Yongpeng Shi ◽  
Mingfeng Liu ◽  
Ao Zhang ◽  
Yi-Lun Hong ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Layer Structure ◽  
Atomic Layer ◽  
Type I ◽  
Hybrid Functional ◽  
Functional Theory ◽  
Valence Electrons ◽  
Nonmagnetic Metals ◽  
Standard Density

AbstractThe search for new two-dimensional monolayers with diverse electronic properties has attracted growing interest in recent years. Here, we present an approach to construct MA2Z4 monolayers with a septuple-atomic-layer structure, that is, intercalating a MoS2-type monolayer MZ2 into an InSe-type monolayer A2Z2. We illustrate this unique strategy by means of first-principles calculations, which not only reproduce the structures of MoSi2N4 and MnBi2Te4 that were already experimentally synthesized, but also predict 72 compounds that are thermodynamically and dynamically stable. Such an intercalated architecture significantly reconstructs the band structures of the constituents MZ2 and A2Z2, leading to diverse electronic properties for MA2Z4, which can be classified according to the total number of valence electrons. The systems with 32 and 34 valence electrons are mostly semiconductors. Whereas, those with 33 valence electrons can be nonmagnetic metals or ferromagnetic semiconductors. In particular, we find that, among the predicted compounds, (Ca,Sr)Ga2Te4 are topologically nontrivial by both the standard density functional theory and hybrid functional calculations. While VSi2P4 is a ferromagnetic semiconductor and TaSi2N4 is a type-I Ising superconductor. Moreover, WSi2P4 is a direct gap semiconductor with peculiar spin-valley properties, which are robust against interlayer interactions. Our study thus provides an effective way of designing septuple-atomic-layer MA2Z4 with unusual electronic properties to draw immediate experimental interest.

Study on the optical spectra of the oxygen vacancy in ZnWO4 crystal

2021 ◽  
pp. 2150471
Author(s):  
Gaiping Lian ◽  
Tingyu Liu ◽  
Le Yu
Keyword(s):  
Oxygen Vacancy ◽  
Density Functional ◽  
Defect Formation ◽  
Finite Size ◽  
Optical Spectra ◽  
Functional Method ◽  
Hybrid Functional ◽  
Electron Phonon Coupling ◽  
Correction Scheme ◽  
The Density Functional Theory

ZnWO4 is easy to color, which will reduce the luminous efficiency of the crystal and limit the application of the crystal. In order to study the origin of the color in the crystal, in this paper, the effects of the oxygen vacancy on the optical properties for the ZnWO4 crystal have been studied based on the density functional theory (DFT). The hybrid functional method (HSE) and the finite-size correction scheme (FNV) are used to correct the band edge problem and eliminate the artificial interaction of the charged defects, respectively. On the basis of the corrected defect formation energy, we obtain the optical spectra of the [Formula: see text] and [Formula: see text] centers containing electron-phonon coupling. The calculated absorption and luminescence peaks are at 2.54 eV and 0.79 eV for the [Formula: see text] center and at 2.98 eV and 1.09 eV for the [Formula: see text] center, respectively. The calculated absorption band of the [Formula: see text] center is close to the experimental value of 2.48 eV (500 nm), so we speculate that the coloring of the ZnWO4 crystal is related to the [Formula: see text] center. Meanwhile, the existence of oxygen vacancy makes ZnWO4 crystal to have self-absorption and to increase decay time, which greatly affects the scintillation properties of the crystal.

scholarly journals Thermoelasticity in Organic Semiconductors Determined with Terahertz Spectroscopy and Quantum Quasi-Harmonic Simulations

2020 ◽  
Author(s):  
Peter A. Banks ◽  
Jefferson Maul ◽  
Mark T. Mancini ◽  
Adam C. Whalley ◽  
Alessandro Erba ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Density Functional ◽  
Mechanical Response ◽  
Terahertz Spectroscopy ◽  
Harmonic Approximation ◽  
Low Frequency ◽  
Intermolecular Forces ◽  
State Density ◽  
Experimental Apparatus ◽  
Thermoelastic Response

The thermomechanical response of organic semiconducting solids is an essential aspect to consider in the design of materials for advanced applications, and in particular, flexible electronics. The non-covalent intermolecular forces that exist in organic solids not only result in a diverse set of mechanical properties, but also a critical dependence of those same properties on temperature. However, studying the thermoelastic response of solids is experimentally challenging, often requiring large single-crystals and sensitive experimental apparatus. An alternative contactless approach involves using low-frequency vibrational spectroscopy to characterize the underlying intermolecular forces, and then combining this information with solid-state density functional theory simulations to retrieve the mechanical response of materials. This methodology leverages recent advances in the quasi-harmonic approximation to predict the temperature evolution of crystalline structures, dynamics, and associated forces, and then utilizes this information to determine the elastic tensor as a function of temperature. Here, this methodology is illustrated for two prototypical organic semiconducting crystals, rubrene and BTBT, and suggests a new alternative means to characterizing the thermoelastic response of organic materials.

scholarly journals Theoretical Study of Solvent Effects on the Electronic and Thermodynamic Properties of Tetrathiafulvalene (TTF) Molecule Based on DFT

2021 ◽  
pp. 42-54
Author(s):  
Rabiu Nuhu Muhammad ◽  
N. M. Mahraz ◽  
A. S Gidado ◽  
A. Musa
Keyword(s):  
Thermodynamic Properties ◽  
Bond Length ◽  
Density Functional ◽  
Theoretical Study ◽  
Energy Gap ◽  
Basis Set ◽  
Basis Sets ◽  
Frontier Molecular Orbital ◽  
Orbital Energy ◽  
Chemical Hardness

Tetrathiafulvalene () is an organosulfur compound used in the production of molecular devices such as switches, sensors, nonlinear optical devices and rectifiers. In this work, a theoretical study on the effects of solvent on TTF molecule was investigated and reported based on Density Functional Theory (DFT) as implemented in Gaussian 03 package using B3LYP/6-31++G(d,p) basis set. Different solvents were introduced as a bridge to investigate their effects on the electronic structure. The HUMO, LUMO, energy gap, global chemical index, thermodynamic properties, NLO and DOS analysis of the TTF molecule in order to determine the reactivity and stability of the molecule were obtained. The results obtained showed that the solvents have effects on the electronic and non-linear-optical properties of the molecule. The optimized bond length revealed that the molecule has strong bond in gas phase with smallest bond length of about 1.0834Å than in the rest of the solvents. It was observed that the molecule is more stable in acetonitrile with HOMO-LUMO gap and chemical hardness of 3.6373eV and 1.8187eV respectively. This indicates that the energy gap and chemical hardness of TTF molecule increases with the increase in polarity and dielectric constant of the solvents. The computed results agreed with the results in the literature. The thermodynamics and NLO properties calculation also indicated that TTF molecule has highest value of specific heat capacity (Cv), total dipole moment () and first order hyperpolarizability () in acetonitrile, while acetone has the highest value of entropy and toluene has a slightly higher value of zero point vibrational energy (ZPVE) than the rest of the solvents. The results show that careful selection of the solvents and basis sets can tune the frontier molecular orbital energy gap of the molecule and can be used for molecular device applications.

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