scholarly journals Energy frameworks and a topological analysis of the supramolecular features in in situ cryocrystallized liquids: tuning the weak interaction landscape via fluorination

2016 ◽  
Vol 18 (46) ◽  
pp. 31811-31820 ◽  
Author(s):  
Dhananjay Dey ◽  
Subhrajyoti Bhandary ◽  
Sajesh P. Thomas ◽  
Mark A. Spackman ◽  
Deepak Chopra
Keyword(s):  
Weak Interaction ◽  
Weak Interactions ◽  
Topological Analysis ◽  
Fluorine Substitution ◽  
Π Stacking

The weak interactions assist in tuning the growth of π⋯π stacking with fluorine substitution in in situ cryocrystallized liquids.

Electron Density Topological Analysis the Intermolecular Weak Interaction between GeH4 and X(X=He, Ne, Ar and Kr)

2012 ◽  
Vol 251 ◽  
pp. 373-377
Author(s):  
Yan Zhi Liu ◽  
Yan Liu ◽  
Hui An Tang ◽  
Kun Yuan
Keyword(s):  
Conformational Analysis ◽  
Electron Density ◽  
Weak Interaction ◽  
Electrostatic Potential ◽  
Weak Interactions ◽  
Topological Analysis ◽  
Topological Properties ◽  
Related Data ◽  
Experimental Identification ◽  
Nmr Properties

The intermolecular weak interaction between GeH4 and X(X=He, Ne, Ar, Kr) has been studied at MP2/aug-cc-pvtz level. Electron density topological properties of the studied systems have been calculated to investigate the critical points of H…X weak bonds. The molecules electrostatic potential (MESP) image is one of the tools for conformational analysis, and the related data suggests the view of the non-electrostatic weak interaction in nature of the GeH4…X(X=Ar, Kr) systems. To help possible experimental identification of the intermolecular weak interactions described in this work, the frequencies analysis and NMR properties were also calculated at MP2/aug-cc-pvtz level.

scholarly journals Data Parallel Hypersweeps for in Situ Topological Analysis

2020 ◽  
Author(s):  
Petar Hristov ◽  
Gunther H. Weber ◽  
Hamish A. Carr ◽  
Oliver Rubel ◽  
James P. Ahrens
Keyword(s):  
Topological Analysis ◽  
Data Parallel

Controlling the molecular arrangement of racemates through weak interactions: the synergy between π-interactions and halogen bonds

2021 ◽  
Author(s):  
Carlos Romero-Nieto ◽  
A. de Cózar ◽  
Elzbieta Regulska ◽  
John B. Mullenix ◽  
Frank Rominger ◽  
...  
Keyword(s):  
Weak Interactions ◽  
Halogen Bonds ◽  
Π Interactions ◽  
Molecular Arrangement ◽  
Π Stacking

The combination of halogend bonds from PO and N-moieties with π-stacking leads to sort out R- and S-isomers into homoleptic, porous assemblies.

Assisted π-stacking: a strong synergy between weak interactions

2018 ◽  
Vol 54 (86) ◽  
pp. 12186-12189 ◽  
Author(s):  
Soumik Sao ◽  
Sumit Naskar ◽  
Narottam Mukhopadhyay ◽  
Mousumi Das ◽  
Debangshu Chaudhuri
Keyword(s):  
Weak Interactions ◽  
Π Stacking

An exceptionally strong synergy between aromatic π-stacking and n → π* interaction.

Electroweak Interactions and W, Z Boson Properties

2020 ◽  
Author(s):  
Maarten Boonekamp ◽  
Matthias Schott
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Top Quark ◽  
Quantum Electrodynamics ◽  
Weak Interactions ◽  
Higgs Field ◽  
Nuclear Research ◽  
Strong Interactions ◽  
Weak Boson ◽  
The Standard Model

With the huge success of quantum electrodynamics (QED) to describe electromagnetic interactions in nature, several attempts have been made to extend the concept of gauge theories to the other known fundamental interactions. It was realized in the late 1960s that electromagnetic and weak interactions can be described by a single unified gauge theory. In addition to the photon, the single mediator of the electromagnetic interaction, this theory predicted new, heavy particles responsible for the weak interaction, namely the W and the Z bosons. A scalar field, the Higgs field, was introduced to generate their mass. The discovery of the mediators of the weak interaction in 1983, at the European Center for Nuclear Research (CERN), marked a breakthrough in fundamental physics and opened the door to more precise tests of the Standard Model. Subsequent measurements of the weak boson properties allowed the mass of the top quark and of the Higgs Boson to be predicted before their discovery. Nowadays, these measurements are used to further probe the consistency of the Standard Model, and to place constrains on theories attempting to answer still open questions in physics, such as the presence of dark matter in the universe or unification of the electroweak and strong interactions with gravity.

Two new polymorphic forms of combretastatin A-4, an antitumour agent

2020 ◽  
Vol 76 (10) ◽  
pp. 958-964
Author(s):  
Anita M. Grześkiewicz ◽  
Tomasz Stefański ◽  
Zbigniew Dutkiewicz ◽  
Daria Buśko ◽  
Maciej Kubicki
Keyword(s):  
Weak Interactions ◽  
Topological Analysis ◽  
Monoclinic Form ◽  
Colchicine Binding Site ◽  
Biological Studies ◽  
Antitumour Agent ◽  
Conformational Freedom ◽  
Polymorphic Forms

Two new polymorphic forms of combretastatin A-4 {systematic name: 2-methoxy-5-[(E)-2-(3,4,5-trimethoxyphenyl)ethenyl]phenol, C18H20O5, CA-4}, an inhibitor of tubulin polymerization at the colchicine binding site, were identified. A number of crystallization attempts led to the orthorhombic form, with two molecules in the asymmetric part of the unit cell; obtaining a different form required the experiment to be moved to another laboratory. None of the attempts resulted in the monoclinic form described earlier. The three different forms contain molecules of significantly different geometries, which can be related to conformational freedom, postulated as the result of biological studies. In addition, the packing modes in all three forms are basically different. The structural differences at both the molecular and the supramolecular level have also been studied via calculations of energies and a topological analysis of the electron density. The results confirm the role of weak interactions in the determination of crystal architecture and additionally hint at an explanation for the results of crystallization attempts: the new monoclinic form has significantly lower energy than the form reported earlier.

Topological analysis of {110} slip in an α-iron crystal from in situ atomic force microscopy

2013 ◽  
Vol 61 (17) ◽  
pp. 6453-6465 ◽  
Author(s):  
C. Kahloun ◽  
L.T. Le ◽  
G. Monnet ◽  
M.-H. Chavanne ◽  
E. Ait ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Topological Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Iron Crystal

Weak C—H...O and C—H...π hydrogen bonds and π–π stacking interactions in a series of fourN′-[(E)-(aryl)methylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazides

2015 ◽  
Vol 71 (8) ◽  
pp. 647-652 ◽  
Author(s):  
Thais C. M. Nogueira ◽  
Alessandra C. Pinheiro ◽  
James L. Wardell ◽  
Marcus V. N. de Souza ◽  
Jordan P. Abberley ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Weak Interactions ◽  
The Other ◽  
Stacking Interactions ◽  
Screw Axis ◽  
Chiral Structure ◽  
Π Stacking ◽  
Unit Form ◽  
Protective Groups ◽  
Local Inversion

Oxazolidin-2-ones are widely used as protective groups for 1,2-amino alcohols and chiral derivatives are employed as chiral auxiliaries. The crystal structures of four differently substituted oxazolidinecarbohydrazides, namelyN′-[(E)-benzylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C12H12N3O3, (I),N′-[(E)-2-chlorobenzylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C12H12ClN3O3, (II), (4S)-N′-[(E)-4-chlorobenzylidene]-N-methyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C12H12ClN3O3, (III), and (4S)-N′-[(E)-2,6-dichlorobenzylidene]-N,3-dimethyl-2-oxo-1,3-oxazolidine-4-carbohydrazide, C13H13Cl2N3O3, (IV), show that an unexpected mild-condition racemization from the chiral starting materials has occurred in (I) and (II). In the extended structures, the centrosymmetric phases, which each crystallize with two molecules (AandB) in the asymmetric unit, formA+Bdimers linked by pairs of N—H...O hydrogen bonds, albeit with different O-atom acceptors. One dimer is composed of one molecule with anSconfiguration for its stereogenic centre and the other with anRconfiguration, and possesses approximate local inversion symmetry. The other dimer consists of eitherR,RorS,Spairs and possesses approximate local twofold symmetry. In the chiral structure, N—H...O hydrogen bonds link the molecules intoC(5) chains, with adjacent molecules related by a 21screw axis. A wide variety of weak interactions, including C—H...O, C—H...Cl, C—H...π and π–π stacking interactions, occur in these structures, but there is little conformity between them.

scholarly journals Two Tautomers of Thiobarbituric Acid in One Crystal: The Experimental Charge Density Perspective

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 223
Author(s):  
Anita M. Grześkiewicz ◽  
Maciej Kubicki
Keyword(s):  
Hydrogen Bonds ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Weak Interactions ◽  
Topological Analysis ◽  
Thiobarbituric Acid ◽  
Polymorphic Form ◽  
X Ray Diffraction ◽  
Geometrical Features

High-quality crystals of a certain polymorphic form of thiobarbituric acid containing both keto and enol tautomers in the asymmetric unit were obtained. High-resolution X-ray diffraction data up to sinθ/λ = 1.0 Å−1 were collected and subsequently successfully used for the refining of the multipolar model of electron density distribution. The use of a crystal containing both ketone and enol forms allowed a direct comparison of the topological analysis results and a closer look at the differences between these two forms. The similarities and differences between the deformation densities, electrostatic potentials, Laplacian maps and bond characteristics of the tautomers were analysed. Additionally, the spectrum of the intermolecular interactions was identified and studied from classical, relatively strong N-H···O and O-H···O hydrogen bonds through weaker N-H···S hydrogen bonds to weak interactions (for instance, C-H···O, C-H···S and N···O). The results of these studies point toward the importance of including both the geometrical features and the details of the electron density distribution in the analysis of such weak interactions.

scholarly journals Synthesis, characterization and crystal structure of platinum(II) complexes with thiourea derivative ligands

2018 ◽  
Vol 9 (4) ◽  
pp. 360-368
Author(s):  
Ebru Keskin ◽  
Ummuhan Solmaz ◽  
Gun Binzet ◽  
Ilkay Gumus ◽  
Hakan Arslan
Keyword(s):  
Single Crystal ◽  
Weak Interactions ◽  
Platinum Complexes ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
Thiourea Derivatives ◽  
X Ray ◽  
Π Stacking ◽  
Π Stacking Interaction ◽  
In Cis

Thiourea derivatives [N-(di-n-propylcarbamothioyl)-4-fluorobenzamide (HL1) and N-(di-n-propylcarbamothioyl)-4-bromobenzamide (HL2)] and their platinum complexes have been successfully synthesized and structurally characterized by spectroscopic 1H NMR, 13C NMR, COSY, HMQC, and FT-IR techniques. The structure of both complexes was also confirmed by single crystal X-ray diffraction studies. The study of X-ray single crystal diffraction shows that the supramolecular aggregation of the complexes is stabilized via weak interactions as well as stacking interactions such as C-H···π and π···π. The cis-[Pt(L1-S,O)2 showed C–H···π and π···π stacking interactions, whereas only C–H···π stacking interaction was observed in cis-[Pt(L2-S,O)2]. In addition, the strong classical and non-classical intermolecular hydrogen bonds are not found in the prepared complexes. Therefore, it can be said that the C–H···π and π···π stacking interactions play an important role in the formation of supramolecular structures of the complexes.

Sign in / Sign up

Export Citation Format

Share Document