scholarly journals Visualization of magnesium and rubidium ion hydration in sulfocationite using quantum chemical calculation

2021 ◽  
Vol 65 (6) ◽  
pp. 692-701
Author(s):  
V. S. Soldatov ◽  
T. V. Bezyazychnaya ◽  
E. G. Kosandrovich
Keyword(s):  
Binding Energy ◽  
Ab Initio Calculation ◽  
Molecular Layer ◽  
Binding Energies ◽  
Magnesium Ion ◽  
Water Molecules ◽  
Chemical Calculation ◽  
Ion Hydration ◽  
Coordination Numbers ◽  
Comparable Size

Based on the data of ab initio calculation of the structure of (RSO3)2Mg (H2O)18 and (RSO3Rb)2(H2O)16 clusters, which simulate the structure of swollen sulfostyrene ion exchangers in the corresponding ionic forms and a water cluster of comparable size, the numbers of water molecules directly bound to cations and their coordination numbers, including the oxygen atoms of the sulfonic groups linked to the cation, were calculated. It is shown that the first molecular layer around the magnesium ion is formed from water molecules with the highest binding energy with the cluster, and around the rubidium ion – from the molecules of the nearest environment with the lowest binding energies. This is explained by the fact that the transfer of water molecules from its volume to magnesium hydrate is energetically favorable, but not to rubidium hydrate. Therefore, the magnesium ion builds its hydrate mainly from water molecules with the highest binding energy in order to obtain the greatest energy gain, and the rubidium ion – from molecules with the lowest energy, which provides the smallest energy loss.

The binding energies of trialkylgermanium cations to water molecules studied by high pressure mass spectrometry

1987 ◽  
Vol 65 (9) ◽  
pp. 2146-2148 ◽  
Author(s):  
John Alfred Stone ◽  
Wilhelmus Johannes Wytenburg
Keyword(s):  
Mass Spectrometry ◽  
High Pressure ◽  
Electron Beam ◽  
Binding Energy ◽  
Thermodynamic Data ◽  
Binding Energies ◽  
Water Molecules ◽  
Pulsed Electron Beam

The binding energies of H2O to R3Ge+ have been measured using pulsed electron beam, high pressure mass spectrometry. van't Hoff plots have yielded thermodynamic data (ΔH0, ΔS0) for the reactions, [5], [Formula: see text]and [7], [Formula: see text]. [Formula: see text] decreases with increasing size of R (CH3 28.6 ± 0.5 kcal mol−1, C4H9 20.6 ± 1.2 kcal mol−1) while [Formula: see text] shows much less change (34.4 ± 0.9 to 30.3 ± 2.8 cal K−1 mol−1). Comparison with data for (CH3)3M+ (M = Si, Sn) shows that binding energy decreases with increasing size of M.

A DFT study of spherands containing five anisyl groups — Highly preorganized to bind the alkali metal

2006 ◽  
Vol 84 (8) ◽  
pp. 1045-1049 ◽  
Author(s):  
Shabaan AK Elroby ◽  
Kyu Hwan Lee ◽  
Seung Joo Cho ◽  
Alan Hinchliffe
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Density Functional ◽  
Ionic Radius ◽  
Binding Energies ◽  
Cavity Size ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Good Agreement

Although anisyl units are basically poor ligands for metal ions, the rigid placements of their oxygens during synthesis rather than during complexation are undoubtedly responsible for the enhanced binding and selectivity of the spherand. We used standard B3LYP/6-31G** (5d) density functional theory (DFT) to investigate the complexation between spherands containing five anisyl groups, with CH2–O–CH2 (2) and CH2–S–CH2 (3) units in an 18-membered macrocyclic ring, and the cationic guests (Li+, Na+, and K+). Our geometric structure results for spherands 1, 2, and 3 are in good agreement with the previously reported X-ray diffraction data. The absolute values of the binding energy of all the spherands are inversely proportional to the ionic radius of the guests. The results, taken as a whole, show that replacement of one anisyl group by CH2–O–CH2 (2) and CH2–S–CH2 (3) makes the cavity bigger and less preorganized. In addition, both the binding and specificity decrease for small ions. The spherands 2 and 3 appear beautifully preorganized to bind all guests, so it is not surprising that their binding energies are close to the parent spherand 1. Interestingly, there is a clear linear relation between the radius of the cavity and the binding energy (R2 = 0.999).Key words: spherands, preorganization, density functional theory, binding energy, cavity size.

scholarly journals np-Pair Correlations in the Isovector Pairing Model

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1405
Author(s):  
Feng Pan ◽  
Yingwen He ◽  
Lianrong Dai ◽  
Chong Qi ◽  
Jerry P. Draayer
Keyword(s):  
Binding Energy ◽  
Occupation Number ◽  
Mean Field ◽  
Energy Difference ◽  
Binding Energies ◽  
Pair Correlations ◽  
Isospin Symmetry Breaking ◽  
Pairing Model ◽  
Proton Pairing ◽  
Spin Basis

A diagonalization scheme for the shell model mean-field plus isovector pairing Hamiltonian in the O(5) tensor product basis of the quasi-spin SUΛ(2) ⊗ SUI(2) chain is proposed. The advantage of the diagonalization scheme lies in the fact that not only can the isospin-conserved, charge-independent isovector pairing interaction be analyzed, but also the isospin symmetry breaking cases. More importantly, the number operator of the np-pairs can be realized in this neutron and proton quasi-spin basis, with which the np-pair occupation number and its fluctuation at the J = 0+ ground state of the model can be evaluated. As examples of the application, binding energies and low-lying J = 0+ excited states of the even–even and odd–odd N∼Z ds-shell nuclei are fit in the model with the charge-independent approximation, from which the neutron–proton pairing contribution to the binding energy in the ds-shell nuclei is estimated. It is observed that the decrease in the double binding-energy difference for the odd–odd nuclei is mainly due to the symmetry energy and Wigner energy contribution to the binding energy that alter the pairing staggering patten. The np-pair amplitudes in the np-pair stripping or picking-up process of these N = Z nuclei are also calculated.

Quantum chemical calculation of cation interaction with water molecules and ethylene glycol

2007 ◽  
Vol 48 (1) ◽  
pp. 166-169 ◽  
Author(s):  
A. G. Rozhkova ◽  
E. V. Butyrskaya ◽  
M. V. Rozhkova ◽  
V. A. Shaposhnik
Keyword(s):  
Ethylene Glycol ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Water Molecules ◽  
Chemical Calculation

Interfacial Adhesion of Cu to Self-Assembled Monolayers on SiO2

2001 ◽  
Vol 695 ◽  
Author(s):  
G. Cui ◽  
M. Lane ◽  
K. Vijayamohanan ◽  
G. Ramanath
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Interfacial Adhesion ◽  
Adhesion Energy ◽  
Binding Energies ◽  
Self Assembled Monolayers ◽  
Chemical Binding ◽  
Barrier Materials ◽  
Assembled Monolayers ◽  
Self Assembled

ABSTRACTAs the critical feature size in microelectronic devices continues to decrease below 100 nm, new barrier materials of > 5 nm thickness are required. Recently we have shown that self-assembled monolayers (SAMs) are attractive candidates that inhibit Cu diffusion into SiO2. For SAMs to be used as barriers in real applications, however, they must also promote adhesion at the Cu/dielectric interfaces. Here, we report preliminary quantitative measurements of interfacial adhesion energy and chemical binding energy of Cu/SiO2 interfaces treated with nitrogen-terminated SAMs. Amine-containing SAMs show a ~10% higher adhesion energy with Cu, while interfaces with Cu-pyridine bonds actually show degraded adhesion, when compared with that of the reference Cu/SiN interface. However, X-ray photoelectron spectroscopy (XPS) measurements show that Cu-pyridine and Cu-amine interactions have a factor-of-four higher binding energy than that of Cu-N bonds at Cu/SiN interfaces. The lack of correlation between adhesion and chemical binding energies is most likely due to incomplete coverage of SAMs.

The binding energies of atomic nuclei III. Nuclear forces and the ground state of oxygen 16

1959 ◽  
Vol 253 (1273) ◽  
pp. 186-198 ◽  
Keyword(s):  
Binding Energy ◽  
Electron Scattering ◽  
Ground State ◽  
Binding Energies ◽  
Wave Functions ◽  
Unperturbed System ◽  
Core Radius ◽  
Nuclear Forces ◽  
Potential Core ◽  
Atomic Nuclei

The r. m. s. radius and the binding energy of oxygen 16 are calculated for several different internueleon potentials. These potentials all fit the low-energy data for two nucleons, they have hard cores of differing radii, and they include the Gammel-Thaler potential (core radius 0·4 fermi). The calculated r. m. s. radii range from 1·5 f for a potential with core radius 0·2 f to 2·0 f for a core radius 0·6 f. The value obtained from electron scattering experiments is 2·65 f. The calculated binding energies range from 256 MeV for a core radius 0·2 f to 118 MeV for core 0·5 f. The experimental value of binding energy is 127·3 MeV. The 25% discrepancy in the calculated r. m. s. radius may be due to the limitations of harmonic oscillator wave functions used in the unperturbed system.

Competition between coordination bonds and hydrogen bonding interactions in solvatomorphs of copper(II), cadmium(II) and cobalt(II) complexes with 2,2′-bipyridyl and acetate

2019 ◽  
Vol 234 (2) ◽  
pp. 119-128 ◽  
Author(s):  
José Antônio do Nascimento Neto ◽  
Cameron Capeletti da Silva ◽  
Leandro Ribeiro ◽  
Ana Karoline Silva Mendanha Valdo ◽  
Felipe Terra Martins
Keyword(s):  
Hydrogen Bonding ◽  
Dft Calculations ◽  
Organic Molecules ◽  
Energy Difference ◽  
Water Molecules ◽  
Coordination Numbers ◽  
Lattice Water ◽  
Hydrogen Bonding Interactions ◽  
Metal Organic ◽  
Coordination Bonds

Abstract The delicate balance among conformation, coordination bonds and hydrogen bonding has been probed in solvatomorphs of known metal-organic molecules synthesised from copper(II), cadmium(II) and cobalt(II) with acetate (OAc) and 2,2′-bipyridine (bipy). The Cu(OAc)2(bipy) complex, isolated as a pentahydrate, has the acetate ligands oriented to opposite sides of the coordination square plane. DFT calculations show the energy difference between this structure and a syn form amount to approximately 16 kJ/mol. The presence of lattice water enables the formation of O–H···O hydrogen bonds with the acetate ligands. Different coordination numbers and energies are found as a function of the number of water molecules co-crystallising in the Cd(OAc)2(bipy)(OH2)·3H2O and [Co(OAc)(bipy)2](OAc)·3H2O complexes.

Syntheses and crystal structures of two magnesium–tetrazole compounds in salt and polymeric forms

2015 ◽  
Vol 71 (3) ◽  
pp. 222-228 ◽  
Author(s):  
Mohamed Abdellatif Bensegueni ◽  
Aouatef Cherouana ◽  
Slimane Dahaoui
Keyword(s):  
Alkaline Earth ◽  
Three Dimensional ◽  
Polymer Chains ◽  
Magnesium Ion ◽  
Water Molecules ◽  
Compound I ◽  
Hydrothermal Conditions ◽  
One Dimensional ◽  
Polymeric Chains ◽  
Hydrogen Bonded

Two alkaline earth–tetrazole compounds, namelycatena-poly[[[triaquamagnesium(II)]-μ-5,5′-(azanediyl)ditetrazolato-κ3N1,N1′:N5] hemi{bis[μ-5,5′-(azanediyl)ditetrazolato-κ3N1,N1′:N2]bis[triaquamagnesium(II)]} monohydrate], {[Mg(C2HN9)(H2O)3][Mg2(C2HN9)2(H2O)6]0.5·H2O}n, (I), and bis[5-(pyrazin-2-yl)tetrazolate] hexaaquamagnesium(II), (C5H3N6)[Mg(H2O)6], (II), have been prepared under hydrothermal conditions. Compound (I) is a mixed dimer–polymer based on magnesium ion centres and can be regarded as the first example of a magnesium–tetrazolate polymer in the crystalline form. The structure shows a complex three-dimensional hydrogen-bonded network that involves magnesium–tetrazolate dimers, solvent water molecules and one-dimensional magnesium–tetrazolate polymeric chains. The intrinsic cohesion in the polymer chains is ensured by N—H...N hydrogen bonds, which formR22(7) rings, thus reinforcing the propagation of the polymer chain along theaaxis. The crystal structure of magnesium tetrazole salt (II) reveals a mixed ribbon of hydrogen-bonded rings, of typesR22(7),R22(9) andR24(10), running along thecaxis, which are linked byR24(16) rings, generating a 4,8-cflunet.

scholarly journals Advances in the Treatment of Explicit Water Molecules in Docking and Binding Free Energy Calculations

2020 ◽  
Vol 26 (42) ◽  
pp. 7598-7622 ◽  
Author(s):  
Xiao Hu ◽  
Irene Maffucci ◽  
Alessandro Contini
Keyword(s):  
Drug Discovery ◽  
Binding Free Energy ◽  
Docking Studies ◽  
Free Energy Calculations ◽  
Binding Energies ◽  
New Drugs ◽  
Water Molecules ◽  
Open Questions ◽  
Dynamics Simulations ◽  
Computational Drug Discovery

Background: The inclusion of direct effects mediated by water during the ligandreceptor recognition is a hot-topic of modern computational chemistry applied to drug discovery and development. Docking or virtual screening with explicit hydration is still debatable, despite the successful cases that have been presented in the last years. Indeed, how to select the water molecules that will be included in the docking process or how the included waters should be treated remain open questions. Objective: In this review, we will discuss some of the most recent methods that can be used in computational drug discovery and drug development when the effect of a single water, or of a small network of interacting waters, needs to be explicitly considered. Results: Here, we analyse the software to aid the selection, or to predict the position, of water molecules that are going to be explicitly considered in later docking studies. We also present software and protocols able to efficiently treat flexible water molecules during docking, including examples of applications. Finally, we discuss methods based on molecular dynamics simulations that can be used to integrate docking studies or to reliably and efficiently compute binding energies of ligands in presence of interfacial or bridging water molecules. Conclusions: Software applications aiding the design of new drugs that exploit water molecules, either as displaceable residues or as bridges to the receptor, are constantly being developed. Although further validation is needed, workflows that explicitly consider water will probably become a standard for computational drug discovery soon.

scholarly journals Chemical Energetics and Atomic Charges Distribution of Variably Sized Hydrated Sulfate Clusters in the light of Density Functional Theory

2021 ◽  
Vol 25 (1) ◽  
pp. 595
Author(s):  
Anant Babu Marahatta
Keyword(s):  
Structural Stability ◽  
Density Functional ◽  
Hydration Number ◽  
Binding Energies ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Atomic Charges ◽  
Electronic Interactions ◽  
Hydrogen Bond Formation ◽  
Depth Analysis

Among the ions classified in the Hofmeister series, the firstly ranked divalent sulfate anion has the strongest hydrating and water-structure making propensity. This unique characteristic actually makes it kosmotropic which causes water molecules to interact each other and contributes to gain structural stability of its hydrated clusters [SO42−(H2O)n]n = 1−40. In this study, few variably sized microhydrated sulfate clusters [SO42−(H2O)n]n = 1−4, 16 are considered separately, and inquired their chemical energetics and atomic charge distributions through ab initio based theoretical model. The main objective of this insight is to specify and interpret their thermodynamic stabilities, binding energies, and specific bonding and electronic interactions quantum mechanically. An in-depth analysis of their change in relative ground state electronic energy with respect to hydration number indicates stronger affinity of the sulfate ion towards water molecules while attaining structural stability in any aqueous type solutions. The mathematically determined values of their binding energy (DE) almost holds up the same with this structural stability order: [SO42−(H2O)16] > [SO42−(H2O)4] > [SO42−(H2O)3] > [SO42−(H2O)2] > [SO42−(H2O)], as reliable as experimentally and molecular dynamics simulation predicted trend. Moreover, the Mulliken derived partial atomic charges feature qualitative charge distribution in them which not only depicts electronic interactions between the specific atoms but also exemplifies the involvement of central sulfate units in hydrogen bond formation with surrounding water molecules.

Sign in / Sign up

Export Citation Format

Share Document