Triclinic conformational polymorph of N,N,N′,N′-tetrakis(2-cyanoethyl)-1,2-ethylenediamine (TCED)

2018 ◽  
Vol 73 (5) ◽  
pp. 305-309
Author(s):  
Bartłomiej Bereska ◽  
Krystyna Czaja ◽  
Błażej Dziuk ◽  
Bartosz Zarychta ◽  
Krzysztof Ejsmont ◽  
...  
Keyword(s):  
Density Functional ◽  
Crystalline State ◽  
Polymeric Materials ◽  
Molecular Geometry ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Homologous Compounds

AbstractThe crystal and molecular structures of two polymorphs of N,N,N′,N′-tetrakis(2-cyanoethyl)-1,2-ethylenediamine have been characterized by X-ray diffraction along with density functional theory (DFT) studies. The molecules differ from each other by conformation. N,N,N′,N′-tetrakis(2-cyanoethyl)-1,2-ethylenediamine has been synthesized by cyanoethylation of ethylenediamine. Cyanoethylation of vicinal diamines is important for the synthesis of hyperbranched polymeric materials applied as catalysts, surfactants and encapsulating agents in drug delivery systems. The molecular geometry of N,N,N′,N′-tetracyanoethyl-1,2-ethylenediamine is similar to that of homologous compounds. DFT calculations were performed to analyze the differences in the molecular geometry of the studied compounds in a crystalline state and for an isolated molecule.

scholarly journals 2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties

2015 ◽  
Vol 11 ◽  
pp. 2179-2188 ◽  
Author(s):  
Yury A Sayapin ◽  
Inna O Tupaeva ◽  
Alexandra A Kolodina ◽  
Eugeny A Gusakov ◽  
Vitaly N Komissarov ◽  
...  
Keyword(s):  
Density Functional ◽  
Acetic Acid Solution ◽  
Intramolecular Proton Transfer ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Dft Methods ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Derivatives Of

A series of derivatives of 2-hetaryl-1,3-tropolone (β-tropolone) was prepared by the acid-catalyzed reaction of 2-methylbenzoxazoles, 2-methylbenzothiazoles and 2,3,3-trimethylindoline with 3,4,5,6-tetrachloro-1,2-benzoquinone. The molecular structures of the three representative compounds were determined by X-ray crystallography. In crystal and (as shown by the DFT PBE0/6-311+G** calculations) in solution, 2-hetaryl-4,5,6,7-tetrachloro- and 2-hetaryl-5,6,7-trichloro-1,3-tropolones exist in the NH-tautomeric form with a strong resonance-assisted intramolecular N–H···O hydrogen bond. The mechanism of the formation of 1,3-tropolones in the reaction of methylene-active five-membered heterocycles with o-chloranil in acetic acid solution has been studied using density functional theory (DFT) methods. The reaction of 2-(2-benzoxa(thia)zolyl)-5,6,7-trichloro(4,5,6,7-tetrachloro)-1,3-tropolones with alcohols leads to the contraction of the seven-membered tropone ring with the formation of 2-(2-benzoxa(thia)zolyl)-6-alkoxycarbonylphenols. The molecular structure of 2-(2-ethoxycarbonyl-6-hydroxy-3,4,5-trichlorophenyl)benzoxazole has been determined by X-ray diffraction. 2-(2-Benzoxa(thia)zolyl)-6-alkoxycarbonylphenols display intense green fluorescence with anomalous Stokes shifts caused by the excited state intramolecular proton transfer (ESIPT) effects.

Functionalisation of Imidazolin-2-imine to Corresponding Phosphinamine, Chalcogenide (O, S, Se, Te), and Borane Compounds

2015 ◽  
Vol 68 (1) ◽  
pp. 127 ◽  
Author(s):  
Kishor Naktode ◽  
Sayak Das Gupta ◽  
Abhinanda Kundu ◽  
Salil K. Jana ◽  
Hari Pada Nayek ◽  
...  
Keyword(s):  
Good Yield ◽  
Density Functional ◽  
Elemental Sulfur ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Tert Butyl ◽  
Imine Ligands ◽  
Orbital Analysis

1,3-Di-tert-butyl-imidazolin-2-ylidine-1,1-diphenylphosphinamine (2) was prepared from 1,3-di-tert-butyl-imidazolin-2-imine (1) and chlorodiphenylphosphine. Compound 2 was treated further with elemental sulfur, selenium, and tellurium to afford the corresponding chalcogenide derivatives, 1,3-di-tert-butyl-imidazolin-2-ylidine-P,P-diphenyl-phosphinothioicamide (4), 1,3-di-tert-butyl-imidazolin-2-ylidine-P,P-diphenyl-phosphinoselenoicamide (5), and 1,3-di-tert-butyl-imidazolin-2-ylidine-P,P-diphenyl-phosphinotelluroicamide (6) in good yield. 1,3-Di-tert-butyl-imidazolin-2-ylidine-P,P-diphenylphosphinicamide (3) was obtained by dissolving compound 2 in hydrochloric acid solution in THF. The corresponding borane adduct, 1,3-di-tert-butyl-imidazolin-2-ylidine-P,P-diphenyl-phosphinaminoborane (7) was isolated by the reaction of compound 2 and sodium borohydride in good yield. The molecular structures of compounds 2 and 4–7 were established by X-ray diffraction analyses. To analyse the electronic structure of chalcogenides of imidazolin-2-imine ligands, the protonation energies of the oxygen, sulfur, and selenide derivative of ligand 2 were calculated by means of density functional theory. Finally, the charge distribution in compounds 3, 4, and 5 were determined using natural bond orbital analysis.

Structural Properties of Conjugated Molecular Crystals Under high Pressure

2001 ◽  
Vol 665 ◽  
Author(s):  
Georg Heimel ◽  
Egbert Zojer ◽  
Roland Resel ◽  
Peter Pushning ◽  
Kerstin Weinmeier ◽  
...  
Keyword(s):  
Molecular Orientation ◽  
Density Functional ◽  
Molecular Structures ◽  
High Electron ◽  
Conjugated Molecules ◽  
Functional Theory ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Commercial Use ◽  
Atomic Force

ABSTRACTElectro-active organic materials based on conjugated molecules, showing promising optical features in the UV/Vis region combined with high electron mobility and fluorescence quantum yield, are of great interest for both, scientific and commercial use. Since the electro-optical properties of these materials are critically influenced by their the crystal and molecular structures, the goal of our work is to study the nature of the intermolecular interactions by applying hydrostatic pressure. X-Ray powder diffraction experimets were carried out to determine the lattice parameters. These experimental data then served as an input for an optimization of the atomic positions and molecular orientation based on total -energy and atomic-force computations within density functional theory.

π-Electron delocalization in 2-benzoyl-5-phenylpyrazolidin-3-one

2018 ◽  
Vol 73 (8) ◽  
pp. 577-582
Author(s):  
Monika Olesiejuk ◽  
Agnieszka Kudelko ◽  
Katarzyna Gajda ◽  
Błażej Dziuk ◽  
Krzysztof Ejsmont
Keyword(s):  
Hydrogen Bonds ◽  
Density Functional ◽  
Heterocyclic Ring ◽  
Molecular Structures ◽  
Electron Delocalization ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Benzene Rings ◽  
Subsequent Cyclization

AbstractThe crystal and molecular structures of 2-benzoyl-5-phenylpyrazolidin-3-one have been characterized by X-ray diffraction along with density functional theory studies. Cinnamic acid chloride was reacted with benzhydrazide, yielding 2-benzoyl-5-phenylpyrazolidin-3-one. This product was formed in the transformation comprising the nucleophilic addition of benzhydrazide to the styryl fragment of the α,β-unsaturated arrangement and subsequent cyclization. The molecule contains two benzene rings and one five-membered heterocyclic ring with an N–N single bond. The five-membered ring is composed of three atoms of sp3 hybridization and two atoms of sp2 hybridization, which cause the flattening of the heterocyclic ring. The Harmonic Oscillator Model of Aromaticity and Nucleus-Independent Chemical Shift indexes, calculated for the benzene rings, demonstrate that there are no substantial interactions between the regions of π-electron delocalization in the molecule. In the crystal structure, there are N–H···O hydrogen bonds that link the molecules along the crystallographic c axis and weak intermolecular C–H···O hydrogen bonds.

Substituent effects intrans-p,p′-disubstituted azobenzenes: X-ray structures at 100 K and DFT-calculated structures

2014 ◽  
Vol 70 (6) ◽  
pp. 575-579 ◽  
Author(s):  
Katarzyna Gajda ◽  
Bartosz Zarychta ◽  
Zdzisław Daszkiewicz ◽  
Andrzej A. Domański ◽  
Krzysztof Ejsmont
Keyword(s):  
Benzene Ring ◽  
Density Functional ◽  
Substituent Effects ◽  
Molecular Structures ◽  
Functional Theory ◽  
Torsion Angles ◽  
X Ray ◽  
Aromaticity Index ◽  
Homologous Compounds ◽  
Isolated Molecules

The crystal and molecular structures of twopara-substituted azobenzenes with π-electron-donating –NEt2and π-electron-withdrawing –COOEt groups are reported, along with the effects of the substituents on the aromaticity of the benzene ring. The deformation of the aromatic ring around the –NEt2group inN,N,N′,N′-tetraethyl-4,4′-(diazenediyl)dianiline, C20H28N4, (I), may be caused by steric hindrance and the π-electron-donating effects of the amine group. In this structure, one of the amine N atoms demonstrates clearsp2-hybridization and the other is slightly shifted from the plane of the surrounding atoms. The molecule of the second azobenzene, diethyl 4,4′-(diazenediyl)dibenzoate, C18H18N2O4, (II), lies on a crystallographic inversion centre. Its geometry is normal and comparable with homologous compounds. Density functional theory (DFT) calculations were performed to analyse the changes in the geometry of the studied compounds in the crystalline state and for the isolated molecules. The most significant changes are observed in the values of the N=N—C—C torsion angles, which for the isolated molecules are close to 0.0°. The HOMA (harmonic oscillator model of aromaticity) index, calculated for the benzene ring, demonstrates a slight decrease of the aromaticity in (I) and no substantial changes in (II).

On the transferability of QTAIMC descriptors derived from X-ray diffraction data and DFT calculations: substituted hydropyrimidine derivatives

2011 ◽  
Vol 67 (5) ◽  
pp. 425-436 ◽  
Author(s):  
A. A. Rykounov ◽  
A. I. Stash ◽  
V. V. Zhurov ◽  
E. A. Zhurova ◽  
A. A. Pinkerton ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Functional ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Covalent Bonds ◽  
Functional Theory ◽  
X Ray ◽  
Biginelli Compounds ◽  
Empirical Corrections

The combined study of electron-density features in three substituted hydropyrimidines of the Biginelli compound family has been fulfilled. Results of the low-temperature X-ray diffraction measurements and density functional theory (DFT) B3LYP/6-311++G** calculations of these compounds are described. The experimentally derived atomic and bonding characteristics determined within the quantum-topological theory of atoms in molecules and crystals (QTAIMC) were demonstrated to be fully transferable within chemically similar structures such as the Biginelli compounds. However, for certain covalent bonds they differ significantly from the theoretical results because of insufficient flexibility of the atom-centered multipole electron density model. It was concluded that currently analysis of the theoretical electron density provides a more reliable basis for the determination of the transferability of QTAIMC descriptors for molecular structures. Empirical corrections making the experimentally derived QTAIMC bond descriptors more transferable are proposed.

scholarly journals Synthesis, Characterization, Theoretical and Electrochemical Studies of Pyrazoline Derivatives

2020 ◽  
Vol 10 (9) ◽  
pp. 845
Author(s):  
Yahya Ben Soumane ◽  
Abdesselam Baouid ◽  
El Mestafa El Hadrami ◽  
Rachid Idouhli ◽  
Lahcen El Ammari ◽  
...  
Keyword(s):  
Density Functional ◽  
Molecular Geometry ◽  
Copper Surface ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Inhibition Performance ◽  
High Level

<p class="Mabstract">The reaction of 1,3-dipolar cycloaddition of trans-anethole and three different diarylnitrilimines bearing different substituents X= {H, CH<sub>3</sub>, Cl} yield to the creation of three 1,3,4,5-tetrasubstituted pyrazoles. These reactions produce a single regioisomer. These compounds' structures were studied using diverse spectroscopic techniques such as <sup>1</sup>H, <sup>13</sup>C NMR, and HRMS. Afterwards, X-ray diffraction is performed at 5-(4-methoxyphenyl)-4-methyl-1,3-diphenyl-4,5-dihydro-1H-pyrazole. Also, Density Functional Theory (DFT) is performed to characterize these cycloadducts.</p><p class="Mabstract">Moreover, these synthesized compounds' molecular geometry and electronic structures have been studied using high-level ab initio calculations and DFT using the B3LYP functional. All geometries have been optimized at the B3LYP/6-311+G(d,p) basis set with different kinds of solvents. In the end, the protection against corrosion of copper surface is tested using these pyrazolines. As a result, the experimental analysis proved that the obtained cycloadducts belong to the pyrazoline family. Also, X-ray diffraction determined the stereochemistry of these compounds. DFT-based calculations revealed the existence of three stable conformations of each compound. The theoretical study and the experimental spectroscopic data showed perfect matching. The electrochemical investigation indicates that these pyrazoline compounds exhibit a good inhibition performance, preventing the degradation of copper in NaCl (3%) solution with a high inhibition efficiency of 80%.</p>

Substituent Effects and Structure in Substituted Dibenzonaphthyrones

1985 ◽  
Vol 38 (1) ◽  
pp. 97
Author(s):  
H Becker ◽  
CL Raston ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Double Bond ◽  
Substituent Effects ◽  
Molecular Geometry ◽  
Molecular Structures ◽  
The Other ◽  
Carbonyl Groups ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Crystal And Molecular Structures

The crystal and molecular structures of [1]benzopyrano[4,3- c][1]benzopyran-5,11-done (dibenzo-naphthyrone) and three of its symmetrically tetrasubstituted derivatives have been determined by single-crystal X-ray diffraction methods. Only the tetra-t-butyl-substituted dibenzonaphthyrone was found to deviate significantly from planarity by having the two carbonyl groups folded and 'syn'-oriented relative to the plane of the connecting ethylene double bond. The dihedral angle between the two aromatic rings was found to be 25. The molecular geometry of all the other dibenzo-naphthyrones in their crystalline states is characterized by planarity, and their structures are centrosymmetric.

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.

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