scholarly journals Crystal structure, spectral characterization, molecular modeling studies and structural effects of the proton transfer process for (E)-5-methoxy-2-[(3,4-dimethylphenylimino) methyl]phenol

2017 ◽  
Vol 36 (2) ◽  
pp. 265
Author(s):  
Basak Kosar Kirca ◽  
Gonca Ozdemir Tarı ◽  
Cıgdem Albayrak Kastas ◽  
Mustafa Odabasoglu ◽  
Orhan Buyukgungor
Keyword(s):  
Proton Transfer ◽  
Dft Calculations ◽  
Density Functional ◽  
Tautomeric Form ◽  
Bond Distance ◽  
Molecular Geometry ◽  
Spectroscopic Properties ◽  
Intramolecular Proton Transfer ◽  
X Ray ◽  
Pes Scan

The main purpose of this study is to characterize a new organic material, (E)-5-methoxy-2-[(3,4-dimethylphenylimino)methyl]phenol, which was synthesized and grown as a single crystal. The molecular structure and spectroscopic properties of the ortho-hydroxy Schiff base compound were determined by X-ray diffraction analysis, Fourier-transform infrared (FT-IR), ultraviolet-visible (UV-Vis) and nuclear magnetic resonance (NMR) spectroscopy techniques, experimentally and computationally with density functional theory (DFT) calculations. X-ray and UV-Vis studies show that the compound exists in an OH tautomeric form in the solid and solvent media. The gas phase geometry optimizations of two possible forms of the title compound, resulting from the prototropic tautomerism, were obtained using DFT calculations at the B3LYP/6-311G+(d,p) level of theory. A relaxed potential energy surface (PES) scan was performed based on the optimized geometry of the OH tautomeric form by varying the redundant internal coordinate, the O-H bond distance. According to the PES scan process, the molecular geometry is strongly affected by the intramolecular proton transfer. The calculated first hyperpolarizability indicates that the compound could be a good material for non-linear optical applications. 

scholarly journals Structure determination, vibrational bands and chemical shift assignments of 3-(4-(3-(2,5-dimethylphenyl)-3-methylcyclobutyl)thiazol-2-yl)-2-(o-tolyl)thiazolidin-4-one: A combined experimental and quantum chemical density-functional theory studies

2019 ◽  
Vol 38 (2) ◽  
pp. 183
Author(s):  
Fatih Şen
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Chemical Shifts ◽  
Molecular Geometry ◽  
Molecular Structures ◽  
Structural Bond ◽  
X Ray ◽  
X Ray Crystallography ◽  
13C Nuclear Magnetic Resonance ◽  
Experimental Findings

This paper report is an analysis of the title compound by means of X-ray crystallography, FT-IR, NMR and DFT calculations, in the context of structural and spectral characterization. The crystal and molecular structures of the compound were determined by single-crystal X-ray diffraction (SCXRD). Fourier Transform Infrared (FTIR) spectrum was recorded in the range from 400 cm–1 to 4000 cm–1. The 1H and 13C nuclear magnetic resonance (NMR) spectra were also recorded. DFT calculations were employed to support X-ray molecular geometry and calculate IR and NMR (1H and 13C) spectral bands. The structural (bond lengths, bond angles, torsion angles) and spectral (vibrational modes and chemical shifts) parameters obtained from DFT levels (B3LYP/6-31G(d,p) and B3LYP/6-31G+(d,p)) were compared with experimental findings, and an excellent harmony between the two data was ascertained.

scholarly journals Nitrile-Substituted 2-(Oxazolinyl)-Phenols: Minimalistic Excited-State Intramolecular Proton Transfer (ESIPT)-Based Fluorophores

2020 ◽  
Author(s):  
Dominik Göbel ◽  
Daniel Duvinage ◽  
Tim Stauch ◽  
Boris Nachtsheim
Keyword(s):  
Excited State ◽  
Solid State ◽  
Proton Transfer ◽  
Density Functional ◽  
Intramolecular Proton Transfer ◽  
Crystal Structure Analysis ◽  
Quantum Yields ◽  
Functional Theory ◽  
Emission Properties ◽  
Emission Enhancement

Herein, we present minimalistic single-benzene, excited-state intramolecular proton transfer (ESIPT) based fluorophores as powerful solid state emitters. The very simple synthesis gave access to all four regioisomers of nitrile-substituted 2(oxazolinyl)phenols (MW = 216.1). In respect of their emission properties they can be divided into aggregation-induced emission enhancement (AIEE) luminophores (1-CN and 2-CN), dual state emission (DSE) emitters (3-CN) and aggregation-caused quenching (ACQ) fluorophores (4‐CN). Remarkably, with compound 1-CN we discovered a minimalistic ESIPT based fluorophore with extremely high quantum yield in the solid state ΦF = 87.3% at λem = 491 nm. Furthermore, quantum yields in solution were determined up to ΦF = 63.0%, combined with Stokes shifts up till 11.300 cm–1. Temperature dependent emission mapping, crystal structure analysis and time-dependent density functional theory (TDDFT) calculations gave deep insight into the origin of the emission properties.<br>

scholarly journals Synthesis, Crystal Structure, Thermal Analysis, and DFT Calculations of Molecular Copper(II) Chloride Complexes with Bitopic Ligand 1,1,2,2-tetrakis(pyrazol-1-yl)ethane

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 222
Author(s):  
Lider ◽  
Sukhikh ◽  
Smolentsev ◽  
Semitut ◽  
Filatov ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Coordination Compounds ◽  
Density Functional ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Chloride Complexes ◽  
Functional Theory ◽  
X Ray ◽  
Lattice Water ◽  
Ir Bands

Two binuclear coordination compounds of Cu(II) chloride with the bitopic ligand 1,1,2,2-tetrakis(pyrazol-1-yl)ethane (Pz4) of the composition [Cu2(µ2Pz4)(DMSO)2Cl4]·4H2O and [Cu2(µ2Pz4)(DMSO)2Cl4]∙2DMSO were prepared and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction, and powder diffraction analysis. It was shown that in contrast to silver(I) and copper(II) nitrates, copper(II) chloride forms discrete complexes instead of coordination polymers. The supramolecular structure of the complex [Cu2(µ2Pz4)(DMSO)2Cl4]·4H2O with lattice water molecules is formed by OH···Cl and OH···O hydrogen bonds. Density functional theory (DFT) calculations of vibrational frequencies of the ligand and its copper(II) complex allowed for assigning IR bands to specific vibrations.

The effect of water-mediated catalysis on the intramolecular proton-transfer reactions of the isomers of 5-chlorouracil: a theoretical study

2019 ◽  
Vol 75 (5) ◽  
pp. 554-561
Author(s):  
Jian Zhang ◽  
Xiu Li
Keyword(s):  
Proton Transfer ◽  
Density Functional ◽  
Dft Method ◽  
Intramolecular Proton Transfer ◽  
Transfer Reactions ◽  
Energy Barriers ◽  
Transfer Energy ◽  
Geometrical Structures ◽  
Proton Transfer Reactions ◽  
Mediated Catalysis

The geometrical structures and thermal energies (E), enthalpies (H) and Gibbs free energies (G) of 13 isomers of 5-chlorouracil (5ClU) in the gas and water phases were investigated using the density functional theory (DFT) method at the M06-2X/6-311++g(3df,3pd) level. The isomers of 5ClU can be microhydrated at different molecular target sites. The mono- and dihydrated forms are the most stable in both the gas and water phases, and, because of the intermolecular interactions, the hydrations lead to a degree of change in the stability trend. Two types of isomerizations were considered: the internal H—O bond rotations in which the H atom rotates 180° around the C—O bond and the intramolecular proton-transfer reactions in which an H atom is transferred between an O atom and a neighbouring N atom. The forward and backward energy barriers for isomerizations of nonhydrated 5ClU were calculated. In addition, 16 optimized transition-state structures for water-mediated catalysis on isomerizations of 5ClU were investigated. The forward and backward proton-transfer energy barriers of water-mediated catalysis on isomerizations of 5ClU were obtained. The results indicate that the catalytic effect of two H2O molecules is much greater than that of one H2O molecule in isomerizations of 5ClU.

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.

scholarly journals 2-(benzimidazol-2-yl)-3-hydroxychromone derivatives: spectroscopic properties and a possibile alternative intramolecular proton phototransfer

2008 ◽  
Vol 6 (3) ◽  
pp. 443-449 ◽  
Author(s):  
D. Svechkarev ◽  
G. Karpushina ◽  
L. Lukatskaya ◽  
A. Doroshenko
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Experimental Evidence ◽  
Spectroscopic Properties ◽  
Intramolecular Proton Transfer ◽  
Fluorescent Properties ◽  
Theoretical Possibility ◽  
Proton Phototransfer

AbstractThree 2-(benzimidazol-2-yl)-3-hydroxychromone derivatives were synthesized. Their spectroscopic and fluorescent properties, due to excited state intramolecular proton transfer (ESIPT) from OH to carbonyl, were studied. Theoretical possibility of an alternative intramolecular H-bonding and experimental evidence for such behavior are discussed.

Competitive excited-state single or double proton transfer mechanisms for bis-2,5-(2-benzoxazolyl)-hydroquinone and its derivatives

2015 ◽  
Vol 17 (18) ◽  
pp. 11990-11999 ◽  
Author(s):  
Jinfeng Zhao ◽  
Junsheng Chen ◽  
Jianyong Liu ◽  
Mark R. Hoffmann
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Proton Transfer ◽  
Density Functional ◽  
Intramolecular Proton Transfer ◽  
Time Dependent ◽  
Functional Theory ◽  
Double Proton Transfer ◽  
Transfer Mechanisms ◽  
Dependent Density

The excited state intramolecular proton transfer (ESIPT) mechanism of HBO, BBHQ and DHBO have been investigated using time-dependent density functional theory (TDDFT).

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