Day: December 7, 2022

Thiele, Nikki A. published the artcileRapid Dissolution of BaSO₄ by Macropa, an 18-Membered Macrocycle with High Affinity for Ba²⁺, Related Products of pyridine-derivatives, the publication is Journal of the American Chemical Society (2018), 140(49), 17071-17078, database is CAplus and MEDLINE.

Insoluble BaSO₄ scale is a costly and time-consuming problem in the petroleum industry. Clearance of BaSO₄-impeded pipelines requires chelating agents that can efficiently bind Ba²⁺, the largest nonradioactive +2 metal ion. Due to the poor affinity of currently available chelating agents for Ba²⁺, however, the dissolution of BaSO₄ remains inefficient, requiring very basic solutions of ligands. In this study, we investigated three diaza-18-crown-6 macrocycles bearing different pendent arms for the chelation of Ba²⁺ and assessed their potential for dissolving BaSO₄ scale. Remarkably, the bis-picolinate ligand macropa exhibits the highest affinity reported to date for Ba²⁺ at pH 7.4 (log K’ = 10.74), forming a complex of significant kinetic stability with this large metal ion. Furthermore, the BaSO₄ dissolution properties of macropa dramatically surpass those of the state-of-the-art ligands DTPA and DOTA. Using macropa, complete dissolution of a molar equivalent of BaSO₄ is reached within 30 min at room temperature in pH 8 buffer, conditions under which DTPA and DOTA only achieve 40% dissolution of BaSO₄. When further applied for the dissolution of natural barite, macropa also outperforms DTPA, showing that this ligand is potentially valuable for industrial processes. Collectively, this work demonstrates that macropa is a highly effective chelator for Ba²⁺ that can be applied for the remediation of BaSO₄ scale.

Journal of the American Chemical Society published new progress about 1128304-86-8. 1128304-86-8 belongs to pyridine-derivatives, auxiliary class Pyridines, name is 6,6′-((1,4,10,13-Tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)bis(methylene))dipicolinic acid, and the molecular formula is C10H15NO, Related Products of pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Hu, Aohan published the artcileMacrocyclic Ligands with an Unprecedented Size-Selectivity Pattern for the Lanthanide Ions, COA of Formula: C26H36N4O8, the publication is Journal of the American Chemical Society (2020), 142(31), 13500-13506, database is CAplus and MEDLINE.

Lanthanides (Ln³⁺) are critical materials used for many important applications, often as coordination compounds Tuning the thermodn. stability of these compounds is a general concern, which is not readily achieved due to the similar coordination chem. of lanthanides. Herein, the authors report two 18-membered macrocyclic ligands called macrodipa and macrotripa that show for the first time a dual selectivity toward both the light, large Ln³⁺ ions and the heavy, small Ln³⁺ ions, as determined by potentiometric titrations The lanthanide complexes of these ligands were investigated by NMR spectroscopy and x-ray crystallog., which revealed the occurrence of a significant conformational toggle between a 10-coordinate Conformation A and an 8-coordinate Conformation B that accommodates Ln³⁺ ions of different sizes. The origin of this selectivity pattern was further supported by d. functional theory (DFT) calculations, which show the complementary effects of ligand strain energy and metal-ligand binding energy that contribute to this conformational switch. This work demonstrates how novel ligand design strategies can be applied to tune the selectivity pattern for the Ln³⁺ ions.

Journal of the American Chemical Society published new progress about 1128304-86-8. 1128304-86-8 belongs to pyridine-derivatives, auxiliary class Pyridines, name is 6,6′-((1,4,10,13-Tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)bis(methylene))dipicolinic acid, and the molecular formula is C26H36N4O8, COA of Formula: C26H36N4O8.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Louw, Stefan published the artcileHigh-efficiency hydrophilic interaction chromatography by coupling 25 cm × 4.6 mm ID × 5 μm silica columns and operation at 80°C, Safety of 4-Amino-2-picoline, the publication is Journal of Chromatography A (2010), 1217(4), 514-521, database is CAplus and MEDLINE.

Recently, hydrophilic interaction chromatog. (HILIC) has emerged as a valuable orthogonal tool to reversed-phase liquid chromatog. (RP-LC) as it allows for resolution of highly polar ionisable compounds The relationships between separation efficiency, column length and speed of anal. for 4.6 mm ID × 5 μm silica particle columns in HILIC are demonstrated using kinetic plots. The kinetic plots constructed for conventional pressure systems operating at 350 bar and at 30° and 80° are confirmed using exptl. data for different column lengths. Efficiencies of more than 130,000 theor. plates could be achieved by connecting up to six columns of 25 cm. As expected, a significant gain in anal. speed without loss of efficiency could be obtained by operating at 80° compared to 30°. The advantages of using long columns in HILIC in combination with elevated column temperature for the pharmaceutical industry are illustrated using test mixtures comprised of com. available ionisable compounds (including some containing functional groups with potential genotoxic typical structural alerts) as well as real polar ionisable pharmaceuticals.

Journal of Chromatography A published new progress about 18437-58-6. 18437-58-6 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 4-Amino-2-picoline, and the molecular formula is C6H8N2, Safety of 4-Amino-2-picoline.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Li, Guoping published the artcilePost-chromatographic dicationic ionic liquid-based charge complexation for highly sensitive analysis of anionic compounds by ultra-high-performance supercritical fluid chromatography coupled with electrospray ionization mass spectrometry, Category: pyridine-derivatives, the publication is Analytical Chemistry (Washington, DC, United States) (2021), 93(3), 1771-1778, database is CAplus and MEDLINE.

A green anal. strategy has been developed for the anal. of 10 perfluorinated compounds (PFCs) incorporating supramol. solvent (SUPRAS)-based extraction and ultra-high-performance supercritical fluid chromatog. (UHPSFC)-tandem mass spectrometry. The SUPRAS was prepared through self-assembly of reverse micelles by mixing heptanol, THF, and water at optimized volume ratios. An imidazolium-based germinal dicationic ionic liquid (DIL), 1,1-bis(3-methylimidazolium-1-yl) butylene difluoride ([C₄(MIM)₂]F₂), was dissolved in the make-up solvent of UHPSFC and introduced post-column but before the electrospray ionization source. After chromatog. separation on a Torus DIOL anal. column (100 mm x 2.1 mm, 1.7μm), the PFC analytes associated with the DIL reagent through charge complexation. The formation of pos. charged complexes resulted in improved ionization efficiency and anal. sensitivity. Enhancement in signal intensity by one to two magnitudes was achieved in the pos. ionization mode compared to the neg. ionization mode without using the dicationic ion-pairing reagent. The developed protocol was applied to 32 samples of real textiles and 6 samples of real food packaging materials, which exhibited great potential for the anal. of anionic compounds

Analytical Chemistry (Washington, DC, United States) published new progress about 47369-00-6. 47369-00-6 belongs to pyridine-derivatives, auxiliary class Pyridine,Salt,Benzene,Organic ligands for MOF materials,Nitrogen containing MOF ligands,Nitrogen containing MOF ligands, name is 1,1′-Diphenyl-[4,4′-bipyridine]-1,1′-diium chloride, and the molecular formula is C22H18Cl2N2, Category: pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

van der Vlugt, Jarl Ivar published the artcileCationic and neutral Ni^II complexes containing a non-innocent PNP ligand: formation of alkyl and thiolate species, Computed Properties of 338800-13-8, the publication is Dalton Transactions (2009), 1016-1023, database is CAplus and MEDLINE.

The synthesis and characterization of a series of cationic and neutral Ni-complexes with the non-innocent pincer ligand (HL = 2,6-bis(di(tert-butyl)phosphinomethyl)pyridine) is discussed. Starting with the dicationic complex [Ni(L)(NCMe)](BF₄)₂ (1), a small series of dicationic and monocationic Ni^II complexes has been prepared Substitution with tert-Bu isocyanide and azide occurs readily in MeCN solution IR spectroscopy provided a practical handle to access the formal valence state of the ligand. For the mono- and dicationic tert-Bu isocyanide derivatives the main vibrational bands in the IR spectra were reproduced quant. by DFT theor. calculations, showing good agreement with the exptl. observed Δν upon dearomatization of the ligand backbone. Using a selective dearomatization-reprotonation methodol. the mononuclear Ni-thiolate derivatives are cleanly generated and their structures have been determined by X-ray crystal structure determination Alternatively, starting from the monocationic species [Ni(L)Cl]BF₄, neutral alkyl derivatives are easily available in a two-step procedure, and these species have been spectroscopically characterized.

Dalton Transactions published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C44H28ClFeN4, Computed Properties of 338800-13-8.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Korstanje, Ties J. published the artcileSynthesis and Characterization of Rhenium(V) Oxo Complexes Bearing PNP-Pincer Ligands, Related Products of pyridine-derivatives, the publication is Organometallics (2014), 33(9), 2201-2209, database is CAplus.

The synthesis of pyridine-based PNP-pincer Re-oxo complexes, with Ph (1, 3), tert-Bu (2), or cyclohexyl (4) groups on the P atoms and either a ReO₂X (1, 2) or a ReCl₂O (3, 4) core is reported. The structures of these compounds were characterized using ¹H, ¹³C, and ³¹P NMR and using x-ray crystallog. for 1 and 4. Compounds 2 and 3 crystallize as the corresponding ReO(OH)X compounds upon their reaction with moisture during the crystallization process. The complexes were tested as catalysts in the oxidation reaction of limonene with H₂O₂, the O atom transfer reaction from pyridine N-oxide to PPh₃, and the dehydration reaction of 1-phenylethanol, but all showed poor catalytic performance. All complexes can be deprotonated at the benzylic arm, and 2 can be deprotonated twice, accompanied by dearomatization of the pyridine ring. 3 and 4 are highly stable in their oxidized forms. The noninnocent behavior shown here could open up possibilities for cooperative catalysis.

Organometallics published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C23H43NP2, Related Products of pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Lazaro, Fernando published the artcileSimultaneous catalytic-fluorometric determination of copper and mercury by flow-injection analysis, Application In Synthesis of 2215-33-0, the publication is Fresenius’ Zeitschrift fuer Analytische Chemie (1985), 320(2), 128-32, database is CAplus.

A catalytic-fluorometric method for the simultaneous determination of Cu(II) and Hg(II) is based on their catalytic effects on the oxidation of dipyridyldiketone phenylhydrazone and 2,2′-dipyridylketone hydrazone, resp., using the flow-injection anal./stopped-flow mode. The errors in the determination of these cations are <10%, with a sampling rate of 45 samples per h and the relative standard deviation is 0.91% and 1.6% for Cu(II) and for Hg(II), resp.

Fresenius’ Zeitschrift fuer Analytische Chemie published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Application In Synthesis of 2215-33-0.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Lazaro, Fernando published the artcileCatalytic-fluorometric determination of EDTA and iron(III) by flow injection analysis. Inhibition methods, Quality Control of 2215-33-0, the publication is Fresenius’ Zeitschrift fuer Analytische Chemie (1985), 321(5), 467-70, database is CAplus.

Methods are described for the direct determination of EDTA and indirect determination of Fe(III), based on the inhibition effect of EDTA on the catalytic action of Cu(II) on the oxidation of 2,2′-dipyridyl ketone hydrazone by H₂O₂ and on the decrease of this inhibition effect in the presence of Fe(III), resp. These methods allow the determination of EDTA in the ranges 0.4-2.0 and 0.2-1.0 μg.mL^-1 for the normal and reversed flow-injection anal. (FIA) modes, resp., and 40-240 ng.mL^-1 for Fe(III) by reversed FIA.

Fresenius’ Zeitschrift fuer Analytische Chemie published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Quality Control of 2215-33-0.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Lazaro Boza, Fernando published the artcileCatalytic-fluorometric determination of copper at the nanograms per milliliter level by flow injection analysis, COA of Formula: C11H10N4, the publication is Analyst (Cambridge, United Kingdom) (1984), 109(3), 333-7, database is CAplus.

A catalytic-fluorometric method for the determination of Cu(II) at the ng/mL level is proposed, based on the catalytic action of Cu(II) on the oxidation of 2,2′-bipyridyl ketone hydrazone (I) by dissolved O. To obtain the maximum anal. signal, 2 steps are necessary: oxidation of I (basic medium) and development of fluorescence (strongly acidic medium). Flow injection anal. is suitable for this determination as it is sensitive and rapid. The calibration graph shows 2 linear intervals, 8-30 ng/mL (relative standard deviation 2.3%) and 40-300 ng/mL (relative standard deviation 2.0%). The sampling frequency is 100 h^-1 for an injected volume of 60 μL.

Analyst (Cambridge, United Kingdom) published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, COA of Formula: C11H10N4.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Lazaro, F. published the artcileStopped-flow injection determination of copper(II) at the ng ml^-1 level, Application of 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, the publication is Analytica Chimica Acta (1984), 177-85, database is CAplus.

A stopped-flow injection method for determination of Cu(II) in the range 0.2-300 ng/mL is proposed, based on the catalytic effect of this ion on the 2,2′-dipyridylketone hydrazone/H₂O₂ reaction. The oxidation product shows an intense blue fluorescence that is monitored at excitation wavelength = 350 nm, emission wavelength = 427 nm. The sampling rate (72/h), relative standard deviation (1.4%), and the lack of interference from most foreign ions allowed application of the method to the determination of Cu in foods and blood serum.

Analytica Chimica Acta published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Application of 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem