Category: 73018-09-4

Beak, Peter; Covington, Johnny B.; Smith, Stanley G.; White, J. Matthew; Zeigler, John M. published the artcile< Displacement of protomeric equilibriums by self-association: hydroxypyridine-pyridone and mercaptopyridine-thiopyridone isomer pairs>, COA of Formula: C5H4ClNO, the main research area is tautomerism pyridinol pyridinethiol association; solvent effect association pyridinol.

Self-association and protomeric equilibrium constants are reported for 2-hydroxypyridine-2-pyridone, 4-hydroxypyridine-4-pyridone and 2-mercaptopyridine-2-thiopyridone isomer pairs in different solvents. These results provide quant. evidence for significant differences in the positions of protomeric equilibrium for self-associated and monomeric species. The 2-substituted isomers are associated as well-known dimers while the 4-substituted systems form oligomers. In polar and H-bonding solvents self-association is substantially reduced. Sterically hindered 2- and 4-pyridones are less associated than unhindered systems. These results imply that determinations and interpretations of protomeric equilibrium should take into account the possible dominance of self-association

Journal of Organic Chemistry published new progress about Self-association. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, COA of Formula: C5H4ClNO.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Forlani, Luciano; Cristoni, Giampiero; Boga, Carla; Todesco, Paolo E.; Del Vecchio, Erminia; Selva, Simona; Monari, Magda published the artcile< Reinvestigation of the tautomerism of some substituted 2-hydroxypyridines>, Formula: C5H4ClNO, the main research area is UV NMR spectrometry tautomerism substituted hydroxypyridines LFER; crystallog nitropyridinone.

The tautomerism of some substituted 2-hydroxypyridines is investigated by UV/Vis- and 1H-, and 13C-NMR spectroscopic methods, with the aid of the N-Me and O-Me fixed parents. NMR spectroscopic data do not allow discrimination between the two tautomeric forms (with the exception of the unsubstituted 2-hydroxypyridine), while UV/Vis-data permit the quant. determination, in different solvents, of the amounts of the two forms. The electronic substituent effect and the change of solvent are discussed. An X-Ray diffraction study carried out on a crystal of 2-hydroxy-5-nitropyridine (7) reveals that this compound, in the solid state, is in the oxo-form.

ARKIVOC (Gainesville, FL, United States) [online computer file] published new progress about Crystal structure. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Formula: C5H4ClNO.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Li, Jing; Zheng, Jiayi; Peng, Xiaoqian; Dai, Zongren; Liu, Weizhen; Deng, Hong; Xi, Beidou; Lin, Zhang published the artcile< NaCl recovery from organic pollutants-containing salt waste via dual effects of aqueous two-phase systems (ATPS) and crystal regulation with acetone>, Name: 6-Chloropyridin-2-ol, the main research area is sodium chloride recovery acetone organic pollutant industrial salt waste.

A large amount of salt waste accompanied with contaminants (e.g., organic pollutants) is produced in chem. production process, causing serious environmental hazards and waste of salt resources. However, there have been few satisfactory treatments for this hazardous waste until now. In this work, a novel strategy for NaCl recovery and organic pollutants removal from the salt waste containing pyridine derivatives was developed by using acetone in salt waste solution The results showed NaCl was effectively recovered (recovery rate, 99.12%), and the TOC value of its saturated solution was reduced from 806.2 to 145.4 mg/L, below the limits (200 mg/L) for chlorine gas and caustic soda production in chlorine alkali plant. Moreover, no pyridine derivatives can be identified through Fourier transform IR spectroscopy (FTIR) test. Mechanism anal. demonstrated the dual effects of acetone as following: (1) acetone and NaCl formed aqueous two-phase systems (ATPS) to remove organic pollutants; 2) acetone, as a crystal regulator, induced NaCl crystals to recrystallize in cubic morphol. with a smooth surface, which enhanced the removal of pollutants. Besides, the acetone-water phase split facilitated the separation of organic pollutants as well as the reuse of acetone. This work proposes a promising and feasible method for salt waste to remove organic pollutants and recover recrystallized NaCl solids, and also provides new insights into the function of acetone on the crystal regulation of salts.

Journal of Cleaner Production published new progress about Centrifugation. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Name: 6-Chloropyridin-2-ol.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

De Kowalewski, D. G.; Contreras, R. H.; De los Santos, C. published the artcile< Carbon-13 and proton NMR spectra of 2-pyridone derivatives>, Category: pyridine-derivatives, the main research area is NMR pyridone derivative; additivity NMR pyridone.

The 13C- and 1H-NMR of substituted pyridines (e.g. I) were studied to determine through additivity properties of 13C shielding constants and of the 13C-1H spin-spin coupling constants, the structure of the ring and of the lateral chains.

Journal of Molecular Structure published new progress about Additivity. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Category: pyridine-derivatives.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Galico, Diogo A.; Ramdani, Rayan; Murugesu, Muralee published the artcile< Phonon-assisted molecular upconversion in a holmium(III)-based molecular cluster-aggregate>, Reference of 73018-09-4, the main research area is holmium gadolinium ytterbium mol cluster aggregate upconversion emission spectra.

Upconversion (UC) is a fascinating process in which higher energy photons can be emitted from excitation by lower energy photons. The current challenge remains in downscaling and effectively achieving upconversion with lanthanide ions at the mol. scale. Here, using a rationally designed mol. cluster-aggregate (MCA), we demonstrate for the first time HoIII ion mol. upconversion. The synthesized MCA exhibits identifiable HoIII green and red UC emissions with a uniquely enhanced red to green ratio as well as a conventional near-IR (NIR) emission. A combined rigid spherical cluster core with reduced mol. vibrations, ideally matched donor and acceptor excited levels via a phonon-assisted mechanism, led to an upconversion quantum yield of 5.24 x 10-6%.

Nanoscale published new progress about Aggregates. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Reference of 73018-09-4.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Qin, Lei; Zhou, Guo-Jun; Yu, You-Zhu; Nojiri, Hiroyuki; Schroder, Christian; Winpenny, Richard E. P.; Zheng, Yan-Zhen published the artcile< Topological Self-Assembly of Highly Symmetric Lanthanide Clusters: A Magnetic Study of Exchange-Coupling ""Fingerprints"" in Giant Gadolinium(III) Cages>, Computed Properties of 73018-09-4, the main research area is gadolinium cage self assembly magnetization exchange interaction crystal structure.

The creation of a perfect hollow nanoscopic sphere of metal centers is clearly an unrealizable synthetic challenge. It is, however, an inspirational challenge from the viewpoint of chem. architecture and also as finite mol. species may provide unique microscopic insight into the origin and onset of phenomena such as topol. spin-frustration effects found in infinite 2D and 3D systems. Herein, we report a series of high-symmetry gadolinium(III) (S = 7/2) polyhedra, Gd20, Gd32, Gd50, and Gd60, to test an approach based on assembling polymetallic fragments that contain different polygons. Structural anal. reveals that the Gd20 cage resembles a dodecahedron; the vertices of the Gd32 polyhedron exactly reveal symmetry Oh; Gd50 displays an unprecedented polyhedron in which an icosidodecahedron Gd30 core is encapsulated by an outer Gd20 dodecahedral shell with approx. Ih symmetry; and the Gd60 shows a truncated octahedron geometry. Exptl. and theor. magnetic studies show that this series produces the expected antiferromagnetic interaction that can be modeled based on classical spins at the Gd sites. From the magnetization analyses, we can roughly correlate the derivative bands to the Gd-O-Gd angles. Such a magneto-structural correlation may be used as “”fingerprints”” to identify these cages.

Journal of the American Chemical Society published new progress about Antiferromagnetic exchange. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Computed Properties of 73018-09-4.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Manteau, Baptiste; Genix, Pierre; Brelot, Lydia; Vors, Jean-Pierre; Pazenok, Sergiy; Giornal, Florence; Leuenberger, Charlotte; Leroux, Frederic R. published the artcile< A General Approach to (Trifluoromethoxy)pyridines: first X-ray Structure Determinations and Quantum Chemistry Studies>, Reference of 73018-09-4, the main research area is general approach synthesis Trifluoromethoxy pyridines crystal structure; ab initio energy profiles rotation trifluoromethoxy methoxy pyridines.

The previously unknown 2-, 3-, and 4-(trifluoromethoxy)pyridines have now become readily accessible by means of an efficient and straightforward large-scale synthesis. Their regioselective functionalization by organometallic methods has been studied and has afforded new and highly important building blocks for life-sciences-oriented research. In addition, the first X-ray crystallog. structure determinations of (trifluoromethoxy)pyridines have been performed. Lowest-energy conformations of (trifluoromethoxy)pyridines and (trifluoromethoxy)pyridinium cations were determined by in silico studies.

European Journal of Organic Chemistry published new progress about Anomeric effect. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Reference of 73018-09-4.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Facelli, Julio C.; Orendt, Anita M.; Contreras, Ruben H.; Tufro, Maria F.; De Kowalewski, Dora G. published the artcile< Ab initio and oxygen-17 NMR studies of the substituent effects on the tautomeric equilibrium in 6-X-(1H)-2-pyridones>, SDS of cas: 73018-09-4, the main research area is keto enol tautomerism pyridone substituent effect; oxygen NMR pyridone tautomerism.

17O chem. shifts are found to be highly sensitive probes in the study of keto-enol tautomeric equilibrium due to the strong sensitivity of these shifts to the coordination of the oxygen atom. The large shielding effect observed, both exptl. and theor., for the carbonyl oxygen atom in 2-pyridone suggests that the carbonyl π-electronic system experiences strong conjugation with the formal C3:C4 double bond and/or the nitrogen lone pair. A Cl or NH2 substitution at position 6 of the pyridine ring shifts the tautomeric equilibrium toward the 2-hydroxypyridine form, while a CH3 substitution results in the keto form being predominant, as is the case in the parent compound

Journal of Physical Chemistry published new progress about Conjugation (bond). 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, SDS of cas: 73018-09-4.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Beak, Peter; Covington, Johnny B.; White, J. Matthew published the artcile< Quantitative model of solvent effects on hydroxypyridine-pyridone and mercaptopyridine-thiopyridone equilibriums: correlation with reaction-field and hydrogen-bonding effects>, Quality Control of 73018-09-4, the main research area is tautomerism pyridone hydroxypyridine; mercaptopyridone thiopyridone tautomerism; solvent effect tautomerization.

A model for the effect of reaction field and H bonding on the relative energies of protomers is applied to the equilibrium between 6-chloro-2-hydroxypyridine and 6-chloro-2-pyridone, 2-mercaptopyridine and 2-thiopyridone, 6-chloro-2-mercaptopyridine and 6-chloro-2-thiopyridone, and 4-mercaptopyridine and 4-thiopyridone in a wide range of solvents. Quant. correlation is obtained by a multivariable anal. In addition to satisfactory statistical tests of the correlation, estimates of the difference in free energies between the isomers in the vapor phase and of the dipole moment component of the reaction-field term are obtained which compare well with the available independent values. These criteria are shown to signal an unacceptable correlation for the case of 2-chloro-4-hydroxypyridine and 2-chloro-4-pyridone. The advantage of this model, which provides an understanding of the effect of mol. environment on protomeric equilibrium in terms of reasonable phys. interactions, over empirical approaches is noted.

Journal of Organic Chemistry published new progress about Free energy. 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Quality Control of 73018-09-4.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Bird, Clive W. published the artcile< Heteroaromaticity. 7. Some quantitative aspects of the tauomerism of hydroxy and mercapto azines>, Synthetic Route of 73018-09-4, the main research area is aromaticity hydroxy azine tautomer crystallog; resonance energy change tautomerization; mercapto azine tautomerism.

Aromaticity indexes have been calculated from crystallog. data for a range of oxo tautomers of hydroxy azines. The differences between these indexes and those for the hydroxy azines lead to values for changes in resonance energies accompanying tautomerization. These values are closely parallel to those previously measured for the same process in aqueous solution

Tetrahedron published new progress about Aromatic nitrogen heterocycles Role: PRP (Properties). 73018-09-4 belongs to class pyridine-derivatives, and the molecular formula is C5H4ClNO, Synthetic Route of 73018-09-4.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem