Tag: M.W:200-300

Related Products of 7181-87-5, An article , which mentions 7181-87-5, molecular formula is C9H11IN2. The compound – 1,3-Dimethyl-1H-benzo[d]imidazol-3-ium iodide played an important role in people’s production and life.

Convenient Preparation and Detailed Analysis of a Series of NHC-Stabilized Phosphorus(I) Dyes and Their Derivatives

A safe, convenient, and P-atom-efficient synthesis of N-heterocyclic-carbene- (NHC-) stabilized phosphorus(I) bromide salts is reported that involves P+ transfer from an easily prepared triphosphenium precursor. The resulting family of phosphamethine cyanine dyes featuring N,N?-dialkyl-substituted 4,5-dimethylimidazole-2-ylidenes (RNHCMe) and benzimidazole-2-ylidenes (RNHCB) (R = Me, Et, iPr) have been fully characterized. We found that increasing N-alkyl group size causes increased twisting of the carbene fragments from the C-P-C plane, which decreases the magnitude of hyperconjugation between the pi-type lone pair on phosphorus and the carbene fragments. This decrease is manifested as changes in the 31P NMR chemical shifts, magnitudes of the P-C coupling constants, and electronic spectra of the cations. The reactivities of these ions toward various oxidants are reported: Oxidation by sulfur generates dithiophosphinium salts, protonation or methylation gives dicationic phosphines, and coordination to 1 or 2 equiv of gold(I) chloride results in mono or bimetallic complexes, respectively.

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The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.14098-44-3, Name is Benzo-15-crown-5, molecular formula is C14H20O5. In a Article£¬once mentioned of 14098-44-3, SDS of cas: 14098-44-3

On the facilitating effect of neutral macrocyclic ligands on the ion transfer across the interface between aqueous and organic solutions – Part III. Competitive facilitated ion-transfer

A theoretical equation of the reversible current-potential curves is derived for the competitive ion-transfer of two kinds of cations present in an aqueous (w) phase simultaneously facilitated by a macrocyclic ligand (L) present in an organic (o) phase. Especially, for the two limiting cases, i.e. case (A): c*Mj (j = 1, 2)?c*L and case (B): c*L?c*Mj (where c*Mj and c*L denote the bulk concentrations of cation Mj in the w-phase and of L in the o-phase, respectively), simple explicit expressions are derived and a method analyzing the facilitated waves is presented. Furthermore, the main part of the theoretical predictions obtained is verified experimentally at 25C by using the ion-transfer-polarographic method with the electrolyte dropping electrode, for the following four combinations: (i) competitive cations: protonated alanine and H+, L: benzo-18-crown-6 ether; (ii) Na+ and Li+, benzo-15-crown-5 ether; (iii) K+ and Na+, dibenzo-18-crown-6 ether; and (iv) Na+ and Ba2+, dibenzo-24-crown-8 ether.

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The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.23190-16-1, Name is (1R,2S)-(?)-2-Amino-1,2-diphenylethanol, molecular formula is C6H5CH(NH2)CH(C6H5)OH. In a Article£¬once mentioned of 23190-16-1, SDS of cas: 23190-16-1

Enantiopure azetidine-2-carboxamides as organocatalysts for direct asymmetric aldol reactions in aqueous and organic media

A family of enantiopure azetidine-2-caboxamides was asymmetrically synthesized, and was examined as organocatalyst in direct aldol reactions. A well chosen chiral azetidine-2-caboxamide was found to smoothly catalyze the direct aldol reaction of various benzaldehydes with acetone in brine, and beta-hydroxy ketones were produced with enantiomeric excess up to 96%. The reaction of benzaldehydes with cyclic ketones also led to the formation of anti-products in diastereomeric ratio up to 99:1 and enantiomeric excess up to 99%.

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Application of 33100-27-5. Let¡¯s face it, organic chemistry can seem difficult to learn. Especially from a beginner¡¯s point of view. Like 33100-27-5, Name is 1,4,7,10,13-Pentaoxacyclopentadecane. In a document type is Review, introducing its new discovery.

Configurational Selection in Azobenzene-Based Supramolecular Systems Through Dual-Stimuli Processes

Azobenzene is one of the most studied light-controlled molecular switches and it has been incorporated in a large variety of supramolecular systems to control their structural and functional properties. Given the peculiar isomeric distribution at the photoexcited state (PSS), azobenzene derivatives have been used as photoactive framework to build metastable supramolecular systems that are out of the thermodynamic equilibrium. This could be achieved exploiting the peculiar E/Z photoisomerization process that can lead to isomeric ratios that are unreachable in thermal equilibrium conditions. The challenge in the field is to find molecular architectures that, under given external circumstances, lead to a given isomeric ratio in a reversible and predictable manner, ensuring an ultimate control of the configurational distribution and system composition. By reviewing early and recent works in the field, this review aims at describing photoswitchable systems that, containing an azobenzene dye, display a controlled configurational equilibrium by means of a molecular recognition event. Specifically, examples include programmed photoactive molecular architectures binding cations, anions and H-bonded neutral guests. In these systems the non-covalent molecular recognition adds onto the thermal and light stimuli, equipping the supramolecular architecture with an additional external trigger to select the desired configuration composition.

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A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 33100-27-5, Name is 1,4,7,10,13-Pentaoxacyclopentadecane, molecular formula is C10H20O5. In a Article£¬once mentioned of 33100-27-5, Product Details of 33100-27-5

Synthetic strategies for the encapsulation of nanoparticles of Ni, Co, and Fe oxides within crystalline microporous aluminosilicates

A synthetic strategy is reported here for the selective containment of oxide nanoparticles of base metals within zeolitic voids of molecular dimensions. The technique, though generally applicable, is specifically illustrated to encapsulate Ni, Co, and Fe oxides within LTA, MFI, and FAU zeolites through hydrothermal framework crystallization in the presence of ligand-protected metal cations. Such ligands contain bidentate amine groups that preclude the precipitation of metal precursors in alkaline synthesis gels, and alkoxysilane moieties that form covalent linkages with nucleating zeolite precursors to enforce metal uptake into crystallized solids. These ligands are removed by subsequent oxidative treatments that nucleate oxide nanoparticles without structural degradation of the zeolites. The clusters are small (<2.5 nm) and uniformly distributed in size, reflecting their constrained growth within zeolite crystals. In contrast with exchange strategies for encapsulation, which lead to grafted cations and dense metal aluminosilicates, these methods form oxide nanoparticles, evident from infrared spectra of samples exposed to CO. Oxide nanoparticles undergo more facile redox cycles than grafted cations or dense aluminosilicates, thus rendering oxide domains more effective oxidation catalysts. The dynamics and stoichiometry of nanoparticle reduction in H2 confirmed the presence of NiO, Co3O4, and Fe2O3 clusters and their more facile reducibility relative to metal aluminosilicates. Ethanol oxidation rates on these clusters were essentially unaffected by exposure to bulky thiol poisons that titrate metal oxide surfaces, reflecting the selective placement of the oxide nanoparticles within the confines of microporous voids, where they are protected from contact by large molecules. These synthetic strategies and guiding principles circumvent long-standing hurdles in the selective encapsulation of base metals, and provide enabling routes for the synthesis of the many metal-zeolite systems that confront similar hurdles. Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.Product Details of 33100-27-5. In my other articles, you can also check out more blogs about 33100-27-5

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Synthetic Route of 4488-22-6, Children learn through play, and they learn more than adults might expect. Science experiments are a great way to spark their curiosity, get their minds active, and encourage them to do something that doesn’t involve a screen. 4488-22-6, C20H16N2. A document type is Article, introducing its new discovery.

Synthesis and reactivity of N,N’-bis

The condensation of a racemic mixture of 2,2′-diamino-1,1′-binaphthylene with two equivalents of o-(diphenylphosphino)benzaldehyde gives a racemic mixture of N,N’-bis in CH2Cl2 gives Cu(Binap-P2N2)Br (II) and (III) in 60percent and 74percent yield, respectively.In II the Binap-P2N2 ligand acts as a tridentate chelating agent, with the two phosphino groups and one of the two imino groups coordinated to the Cu, whereas in III it acts in tetradentate chelating mode.A variable temperature 31P<1H> NMR study of II reveals that the coordinated and the uncoordinated imino groups of the tridentate Binap-P2N2 ligand undergo a facile intramolecular exchange even at -55 deg C.The interaction of I with one equivalent of AgBF4 in CH2Cl2 gives (IV) in 79percent yield.In IV, the Binap-P2N2 ligand acts as a tridentate chelating agent, with the two phosphino groups and one of the two imino groups coordinated to the Ag.The structure of IV has been established by an X-ray diffraction study.The distance between Ag and N(2) is 2.56(1) Angstroem, and the non-bonding distance between Ag and N(1) is > 3.0 Angstroem.Key words: Silver; Copper; Imine; Multidentate ligands; Crystal structure

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Electric Literature of 14098-44-3, An article , which mentions 14098-44-3, molecular formula is C14H20O5. The compound – Benzo-15-crown-5 played an important role in people’s production and life.

Ethynylpyrene Linked Benzocrown Ethers as Fluorescent Sensors for Metal Ions

Substances containing ethynylpyrenes linked to either one or four benzocrown ethers were synthesized, and their absorption and fluorescence spectroscopic responses to metal ions were assessed. Addition of metal perchlorates to solutions of these substances promotes short wavelength shifts in their absorption and fluorescence maxima and increases in their fluorescence intensities. The magnitudes of the fluorescence intensity increases are dependent on the ring size and number of the crown ether and the nature of the metal cation. Association constants for complex formation were calculated using fluorescence intensity versus concentration data. Analysis using Job’s plots showed that the substances containing one benzocrown ether moiety form 1:1 complexes with metal ions. Results of experiments employing repeated addition and removal of Mg(ClO4)2 demonstrate that the ON-OFF fluorescence response can be repeated at least three times. Results of molecular orbital calculations show that complexation with metal ions lowers the energies of both the pi and pi* levels of the ethynylpyrene moiety and that in some cases the vacant orbital on the metal becomes the LUMO of the complex. An explanation of the spectroscopic changes promoted by metal ions is proposed in terms of electrostatic repulsion and structural regulation.

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Reference of 4488-22-6, Catalysts are substances that increase the reaction rate of a chemical reaction without being consumed in the process. 4488-22-6, Name is [1,1′-Binaphthalene]-2,2′-diamine, molecular formula is C20H16N2. In a Article£¬once mentioned of 4488-22-6

Synthesis and X-ray structures of new phosphorus-selenium heterocycles with an E-P(Se)-E? (E, E? = N, S, Se) linkage

Refluxing a toluene solution of Woollins’ reagent, WR, with difunctional aromatic substrates (aryldiamines and aryldithiols) leads to a series of novel five- to seven-membered heterocycles 2a-e, 4a, 4b and 6a-c with an E-P(Se)-E? (E, E? = N, S, Se) linkage in 7-98% isolated yields. This method offers a new approach to the library of phosphorus-selenium heterocyclic compounds. All new compounds have been characterized by IR, 1H, 13C, 31P, 77Se NMR, mass spectrometry and elemental analysis or accurate mass measurement. Four representative X-ray structures are reported.

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Reference of 33100-27-5, Children learn through play, and they learn more than adults might expect. Science experiments are a great way to spark their curiosity, get their minds active, and encourage them to do something that doesn’t involve a screen. 33100-27-5, C10H20O5. A document type is Article, introducing its new discovery.

Derivatives of Borole, XIX. (Borole)dicarbonycobaltate Ions: Synthesis, Structure, and Reactivity

Reduction of the dinuclear (borole)carbonylcobalt complexes <(3,4-R2C4H2BPh)Co(CO)2>2 (3a: R = H, b: R = Me) with Na/Hg in THF at -30 deg C affords the anions <(3,4-R2C4H2BPh)Co(CO)2>– (2a,b-) which can be isolated as crown-5)>+ salts.The structural data of PPh4*2a indicate a strong Co-C(CO) interaction and relatively weak cobalt-to-boron bonding.Methylation of the anions 2a,b- gives labile metal alkyl complexes (3,4-R2C4H2BPh)Co(CO)2Me while protonation and subsequent addition of phosphanes afford boracyclopentenyl complexes as e. g. (C4H5BPh)Co(CO)2(PMe3) (5a).The latter reacts with Ph3CBF4 to give the salt <(C4H4BPh)Co(CO)2(PMe3)>BF4 (6*BF4).At -80 deg C cation 6+ undergoes hydride addition at the carbonyl carbon to give the formyl species (C4H4BPh)Co(CO)(CHO)(PMe3) (7) which transforms to the hydride (C4H4BPh)CoH(CO)(PMe3) (8).At room temperature the same reaction produces 5a.Deuteration studies show that the oxidative formation of 6+ from 5a and the formation of 5a by addition of hydride to 6+ are nonstereospecific processes.Key Words: (Borole)dicarbonylcobalt anions, methylation, protonation / (Boracyclopentenyl)dicarbonyl(phosphane)cobalt complexes, hydride abstraction / (Borole)dicarbonyl(phosphane)cobalt cation, hydride addition

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In an article, published in an article, once mentioned the application of 33100-27-5, Name is 1,4,7,10,13-Pentaoxacyclopentadecane,molecular formula is C10H20O5, is a conventional compound. this article was the specific content is as follows.Formula: C10H20O5

LARIAT ETHERS. 2. THE REMARKABLE SOLVENT DEPENDENCE OF BINDING CONSTANTS IN MACROCYCLIC POLYETHERS BEARING SECONDARY DONOR GROUPS ON FLEXIBLE ARMS

Certain hydroxylated macrocyclic polyethers are found to have considerably diminished binding constants in polar solvents, even when the sidearm does not appear to be large enough to hinder the crown hole.

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