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Planar Benzo[1,2-b:4,5-b′]dithiophene Derivatives Decorated with Nitronyl and Imino Nitroxides
2018
Four weakly antiferromagnetic interacting biradicals of benzo[1,2- b:4,5- b']dithiophene (BDT) and BDT extended with two thiophenes (BDTTh2) linked with nitronyl and imino nitroxides (NN and IN) as BDT-NN, BDT-IN, BDTTh2-NN, and BDTTh2-IN were designed, synthesized, and characterized. Short intermolecular π-π distances were found (3.42 A) for BDT-NN, whereas larger ones were found for BDT-IN (3.54 A) and BDTTh2-NN (3.67 A), respectively. Intramolecular magnetic interaction ( Jintra,exp/ kB) of BDT-NN (-26 K) is much larger than for BDT-IN (-5.3 K), while it is reduced for the dithiophene-extended molecule BDTTh2-NN (-2.3 K). Intermolecular interactions ( zJinter,exp/ kB) of BDT-NN (-6.5 K) …
A Combined Experimental and Theoretical Study of the Ammonium Bifluoride Catalyzed Regioselective Synthesis of Quinoxalines and Pyrido[2,3-b]pyrazines
2015
International audience; Ammonium bifluoride was efficiently used (at a 0.5 mol % loading) to catalyze the cyclocondensation between 1,2-arylenediamines and 1,2-dicarbonyl compounds at room temperature in methanol-water, affording quinoxalines and pyrido[2,3-b]pyrazines in excellent yields. Importantly, 2,8-disubstituted quinoxalines and 3-substituted pyrido[2,3-b]pyrazines were regioselectively formed by reacting aryl glyoxals with 3-methyl-1,2-phenylenediamine and 2,3-diaminopyridine, respectively. Analysis of the DFT reactivity indices allowed to explain the catalytic role of ammonium bifluoride.
Chemical shift reagents in the study of polycyclic alcohols IX—1H NMR spectra of myrtenol and some other primary alcohols
1974
Structure proof of (—)-myrtenol, 3-cyclopentenyl-1-methanol and 5-norbornene-2-endo-methanol has been obtained from their proton magnetic resonance spectra in carbon tetrachloride containing different added amounts of tris(dipivaloylmethanato)europium. For each alcohol, a 1:1 complex structure with Eu(dpm)3 could be computed, in which the calculated pseudocontact shift effects on all skeleton protons of the ring system were consistent with the observed shift effect values. A considerable contact contribution of opposite sign to that of the pseudocontact part of the effect could be estimated for the methylene protons of the CH2OH group.
Synthesis, molecular structures and EPR spectra of the paramagnetic cuboidal clusters with Mo3S4Ga cores
2017
Electron precise [Mo3(l3-S)(l-S)3(diphos)3Br3]Br (diphos = dppe, dmpe) incomplete cuboidal clusters with six cluster skeletal electrons (CSE) were converted into paramagnetic cuboidal [Mo3(GaBr)(l3-S)4- (diphos)3Br3] clusters by treatment with elemental Ga. The new heterobimetallic complexes with nine CSE possess a doublet ground state with the unpaired electron density delocalized over the three molybdenum atoms.
Reagent- and Metal-Free Anodic C-C Cross-Coupling of Aniline Derivatives.
2017
The dehydrogenative cross-coupling of aniline derivatives to 2,2′-diaminobiaryls is reported. The oxidation is carried out electrochemically, which avoids the use of metals and reagents. A large variety of biphenyldiamines were thus prepared. The best results were obtained when glassy carbon was used as the anode material. The electrosynthetic reaction is easily performed in an undivided cell at slightly elevated temperature. In addition, common amine protecting groups based on carboxylic acids were employed that can be selectively removed under mild conditions after the cross-coupling, which provides quick and efficient access to important building blocks featuring free amine moieties.
Corrosion inhibition performance of a structurally well-defined 1,2,3-triazole derivative on mild steel-hydrochloric acid interface
2021
Abstract In the present work, a new 1,4-disubstituted-1,2,3-triazole product, named 4-[1-(4-methoxy-phenyl)-1H-[1,2,3]triazol-4-ylmethyl]-morpholine (MPTM) was successfully synthesized under click chemistry regime. The structure of the new compound that has a rigid triazole moiety and a flexible morpholine ligand has been characterized using 1H NMR, 13C NMR, HRMS, and FTIR spectroscopy. Its inhibition performance for mild steel in acidic medium 1 M HCl has been studied by utilizing a combination of experimental, spectroscopic and computational methods. The electrochemical characterization was carried out by a gravimetric study, electrochemical impedance spectroscopy (EIS), and potentiodynam…
Influence of Substituent and Benzoannulation on Photophysical Properties of 1-Benzoylmethyleneisoquinoline Difluoroborates
2015
A series of 1-benzoylmethyleneisoquinoline difluoroborates were synthesized, and their photophysical properties were determined. The effect of the substituent and benzoannulation on their properties was investigated to make a comparison with recently published results focused on related quinolines. The photophysical properties of isoquinoline derivatives differ from those of quinolines, and the most pronounced differences are found for the fluorescence quantum yields. Both experimental and theoretical approaches were used to explain the observed photophysical properties.
Iron( ii ) and cobalt( ii ) complexes based on anionic phenanthroline-imidazolate ligands: reversible single-crystal-to-single-crystal transformations
2018
A series of low-spin FeII and CoII complexes based on phenanthroline-imidazolate (PIMP) ligands are reported. The FeII complex (H9O4)[Fe(PIMP)3]·(C4H10O)2(H2O) (1a) shows reversible crystalline phase transformations to afford two new phases (H9O4)[Fe(PIMP)3]·(H2O) (1b) and (H9O4)[Fe(PIMP)3]·(C8H18O)(C4H10O)(H2O) (1c) by release of diethyl ether and absorption of diethyl/dibutyl ether, respectively. This reversible uptake/release of solvent molecules is a clear example of single-crystal-to-single-crystal transformation involving a discrete metal complex. On the other hand, the corresponding CoII complex (H9O4)[Co(PIMP)3]·(C4H10O)2(H2O)2 (2) does not exhibit similar phase transformations. In …
Comparative hydroamination of aniline and substituted anilines with styrene on different zeolites, triflate based catalysts and their physical mixtur…
2014
Abstract Catalytic performances of different zeolites (Beta and mordenites), scandium triflate based catalysts, mesoporous UVM-7 encapsulated scandium triflate and physical mixtures prepared under ultrasound irradiation were evaluated in the hydroamination of aniline and substituted anilines with styrene. The performances of these catalysts were controlled by the type of acidity and strength. Thus, the conversion was mainly controlled by the strength of the acid sites and their accessibility, while the selectivity appeared to be controlled by the Lewis/Bronsted type of acidity. Lewis acid catalysts directed the reactions mainly to the formation of the Markovnikov adducts while Bronsted acid…
Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron h…
2018
Reaction of anti-B18H221 with pyridine in neutral solvents gives sparingly soluble B16H18-3',8'-Py23a as the major product (ca. 53%) and B18H20-6',9'-Py22 (ca. 15%) as the minor product, with small quantities of B18H20-8'-Py 4 (ca. 1%) also being formed. The three new compounds 2, 3a and 4 are characterized by single-crystal X-ray diffraction analyses and by multinuclear multiple-resonance NMR spectroscopy. Compound 2 is of ten-vertex nido:ten-vertex arachno two-atoms-in-common architecture, long postulated for a species with borons-only cluster constitution, but previously elusive. Compound 3a is of unprecedented ten-vertex nido:eight-vertex arachno two-atoms-in-common architecture. The si…