Day: February 23, 2021

Electric Literature of 2177-47-1, The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.2177-47-1, Name is 2-Methyl-1H-indene, molecular formula is C10H10. In a Patent£¬once mentioned of 2177-47-1

Metallocene compounds, catalysts comprising them, process for producing an olefin polymer by use of the catalysts, and olefin homo- and copolymers

Certain metallocene compounds are provided that, when used as a component in a supported polymerization catalyst under industrially relevant polymerization conditions, afford high molar mass homo polymers or copolymers like polypropylene or propylene/ethylene copolymers without the need for any alpha-branched substituent in either of the two available 2-positions of the indenyl ligands. The substituent in the 2-position of one indenyl ligand can be any radical comprising hydrogen, methyl, or any other C2-C40 hydrocarbon which is not branched in the alpha-position, and the substituent in the 2-position of the other indenyl ligand can be any C4-C40 hydrocarbon radical with the proviso that this hydrocarbon radical is branched in the beta-position. This metallocene topology affords high melting point, very high molar mass homo polypropylene and very high molar mass propylene-based copolymers. The activity/productivity levels of catalysts including the metallocenes of the present invention are exceptionally high.

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Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Electric Literature of 29841-69-8, Because a catalyst decreases the height of the energy barrier, its presence increases the reaction rates of both the forward and the reverse reactions by the same amount.29841-69-8, Name is (1S,2S)-(-)-1,2-Diphenylethylenediamine, molecular formula is C14H16N2. In a article£¬once mentioned of 29841-69-8

Synthesis and characterization of chiral nickel(II) Schiff base complexes and their CD spectra-absolute configuration correlations

Some nickel(II) complexes of quadridentate Schiff bases prepared from the condensation of 2 mol of 2-hydroxyacetophenone (HACP) or dehydroacetic acid (DHA) with 1 mol of optically active propylene-1,2-diamine (pn), trans-cyclohexane-1,2-diamine (chxn) or 1,2-diphenylethylenediamine (dpen) were synthesized and characterized by EA, IR, UV-vis, and CD spectra. The absolute configurations of the three complexes were determined by X-ray single crystal structure measurement and correlated with CD spectroscopy. In this study, special attention is focussed on the CD signals of the related complexes in the d-d transition region, in the hope of obtaining a tentative correlation between the CD pattern and the absolute configuration about the central metal. A new empirical rule for the assignment of the absolute configuration around the nickel ion in each complex and the handedness of the chiral diamine contained in the Schiff base ligand is put forward. In the case of tetra-coordinated pseudo-planar Ni(II) complexes, the rule can be stated as follows: (i) a positive Cotton effect in the d-d region around 550 nm is assigned to the (S)Deltalambda-configuration for the HACP-(S)-pn-Ni, HACP-(SS)-dpen-Ni, DHA-S-pn-Ni, and DHA-(SS)-dpen-Ni derivatives; and (ii) a concomitant inversion of the Cotton effect in the same range is assigned to the (S)Lambdadelta-configuration for the HACP-(SS)-chxn-Ni and DHA-(SS)-chxn-Ni derivatives.

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Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Catalysts function by providing an alternate reaction mechanism that has a lower activation energy than would be found in the absence of the catalyst. In some cases, the catalyzed mechanism may include additional steps.In a article, 2082-84-0, molcular formula is C13H30BrN, introducing its new discovery. name: N,N,N-Trimethyldecan-1-aminium bromide

Interactions of hyaluronan with oppositely charged surfactants in very diluted solutions in water

The phase behavior of aqueous systems containing hyaluronan, at concentrations between 2 and 100 mg/L, and oppositely charged surfactants was investigated. A fluorescence probe technique revealed the formation of micellar structures on the hyaluronan in homogeneous systems well below the surfactant standard, critical, micellar concentration. Moreover, regions of gel-phase separation were revealed. A detailed phase diagram was, thus, constructed in the very diluted region and the hyaluronan concentration was found to be the main parameter controlling the phase behavior, in contrast to the charge ratio. The stability of hyaluronan-surfactant aggregates in the homogeneous systems while in storage at 4 C (up to three months), against dilution, salt addition and on heating-cooling (between 10 and 50 C) was also investigated. The aggregates were stable while in storage or upon increasing and decreasing the temperature. The dilution of hyaluronan-surfactant complexes or the addition of 0.15 M NaCl led to their disintegration. Finally, systems prepared in a 0.15 M NaCl solution showed that interactions are suppressed and no aggregation below the standard critical micellar concentration was observed.

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Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, Recommanded Product: 1802-30-8, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 1802-30-8, Name is 2,2′-Bipyridine-5,5′-dicarboxylic acid, molecular formula is C12H8N2O4. In a Article, authors is Ziessel, Raymond£¬once mentioned of 1802-30-8

Photocatalysis. Mechanistic studies of homogeneous photochemical water gas shift reaction catalyzed under mild conditions by novel cationic iridium(III) complexes

The photochemical water gas shift reaction (WGSR) catalyzed, under mild conditions (25 C, 1 atm CO, visible light, pH = 7), by [(eta5-Me5C5)IrIII(bpy)X] + (bpy = 2,2?-bipyridine, X = H, Cl), [(eta5-Me5C5)IrIII(phen)X] + (phen = 1,10-phenanthroline, X = H, Cl), or [(eta5-Me5C5)IrIII(bpyRR’)Cl] + (R = R’ = COOH, COOiPr, Br, NO2, NMe2 in the 4,4?-positions or R = R’ = COOH, R = H and R’ – SO3H in the 5,5?-positions of the bpy ligand) has been investigated. A turnover frequency for H2 formation of 32 h-1 was obtained in an aqueous phosphate buffer containing [(eta5-Me5C5)Ir III(bpy-4,4?-(COOH)2Cl]+ as catalyst, over a 7-h irradiation period at a constant CO pressure of 1 atm. An increase of 1 order of magnitude in catalytic activity was observed for the bpy ligand substituted with two carboxylate groups in the 4,4?- or 5,5?-positions or with one sulfonate group in the 5-position (over the nonsubstituted bpy equivalent). Conversely, catalytic activity was lost when the bpy was substituted with two dimethylamino groups. The presence of an electron withdrawing group on the bpy-chelate was shown to decrease the activation energy of the process (Ea = 14.6 kJ mol-1 for R = COOH, Ea = 22.2 kJ mol-1 for R = COOiPr), cf. the unsubsthuted ligand (Ea = 29.6 kJ mol-1 for R = H). Decarboxylation of the intermediate [(eta5-C5Me5)Ir III(bpyRR’)COOH]+ (rate limiting step) seems therefore to be favored by the presence of an electron withdrawing group on the bpy-chelate. Three of the four intermediates involved in the WGS catalytic cycle have been characterized by NMR and FT-IR spectroscopies: (i) the highly reactive [(eta5-Me5C5)IrIII(bpyRR’)CO] 2+ species formed by thermal displacement of the Cl- anion of the starting complex; (ii) the iridium(I) complex [(eta5-Me5C5)IrI(bpyRR’)], formed by decarboxylation of the hydroxycarbonyl complex; and (iii) the hydrido complex [eta5-Me5C5)IrIII(bpyRR’)H] +, formed by protonation of [eta5-Me5C5)IrI(bpyRR’)]. This latter complex (with R = COOH in the 4,4?-position of the bipyridine) has been characterized by a crystal structure determination. The photochemical step of the cycle was found to be the protonation of the hydride generating H2 and the starting complex. The global catalytic system (for [eta5-Me5C5)Ir III(bpy-4,4?-(COOH)2)Cl]+) has a quantum yield of 12.7% at 410 ¡À 5 nm, which is independent of light intensity but strongly dependent on the pH of the solution.

Enzymes are biological catalysts that produce large increases in reaction rates and tend to be specific for certain reactants and products. I hope my blog about is helpful to your research. Recommanded Product: 1802-30-8

Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Catalysts function by providing an alternate reaction mechanism that has a lower activation energy than would be found in the absence of the catalyst. In some cases, the catalyzed mechanism may include additional steps.In a article, 57709-61-2, molcular formula is C14H8N2O4, introducing its new discovery. Quality Control of: 1,10-Phenanthroline-2,9-dicarboxylic acid

An Improved Route for the Synthesis of Guanine Quadruplex Ligand Phen-DC3

The recognition of noncanonical DNA and RNA architectures such as guanine quadruplexes by small molecule ligands has become a promising strategy for anticancer and antiviral applications in recent years, leading to an exponential increase in the number of quadruplex ligands reported in the literature. There is consequently a need for ‘benchmark’ compounds which can be used as controls to facilitate comparisons between novel and previously reported ligands. One candidate for this role is Phen-DC3, which binds with high affinity and selectivity to guanine quadruplexes. To encourage its use in this role, an alternate synthetic route for the production of Phen-DC3 that may be more appropriate for implementation on a large scale is reported. This pathway eliminates the need for several hazardous reagents and increases the overall synthetic yield from 21% to a maximum of 43%.

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Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Synthetic Route of 50446-44-1, The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.50446-44-1, Name is 5′-(4-Carboxyphenyl)-[1,1′:3′,1”-terphenyl]-4,4”-dicarboxylic acid, molecular formula is C27H18O6. In a Article£¬once mentioned of 50446-44-1

Channel partition into nanoscale polyhedral cages of a triple-self-interpenetrated metal-organic framework with high CO2 uptake

Reported herein is a novel porous metal-organic framework (MOF) exhibiting unique nanoscale cages derived from the 3-fold self-interpenetration of chiral eta networks based on trifurcate {Zn2(CO2)3} building blocks and 1,3,5-tris(4-carboxyphenyl)benzene ligands. The attractive self-interpenetrated structural features contribute to the highest CO2 uptake capacity and CO2 binding ability among the interpenetrated MOFs.

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Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Catalysts function by providing an alternate reaction mechanism that has a lower activation energy than would be found in the absence of the catalyst. In some cases, the catalyzed mechanism may include additional steps.In a article, 94928-86-6, molcular formula is C33H27IrN3, introducing its new discovery. Quality Control of: fac-Tris(2-phenylpyridine)iridium

Effect of substitution of methyl groups on the luminescence performance of IrIII complexes: Preparation, structures, electrochemistry, photophysical properties and their applications in organic light-emitting diodes (OLEDs)

A series of dimethyl-substituted tris(pyridylphenyl)iridium(III) derivatives [(n-MePy-n?-MePh)3Ir] [n = 3, n? = 4 (1); n = 4, n? = 4 (2); n = 4, n? = 5 (3); n = 5, n? = 4 (4); n = 5, n? = 5 (5)] have been synthesized and characterized to investigate the effect of the substitution of methyl groups on the solid-state structure and photo- and electroluminescence. The absorption, emission, cyclic voltammetry and electroluminescent performance of 1-5 have also been systematically evaluated. The structures of 2 and 4 have been determined by a single-crystal X-ray diffraction analysis. Under reflux (> 200 C) in glycerol solution, fac-type complexes with a distorted octahedral geometry are predominantly formed as the major components in all cases. Electrochemical studies showed much smaller oxidation potentials relative to Ir(ppy)3 (Hppy = 2-phenylpyridine). All complexes exhibit intense green photoluminescence (PL), which has been attributed to metal-to-ligand charge transfer (MLCT) triplet emission. The maximum emission wavelengths of thin films of 1, 3, 4 and 5 at room temperature are in the range 529-536 nm, while 2 displays a blue-shifted emission band (lambdamax = 512 nm) with a higher PL quantum efficiency (PhiPL = 0.52) than those of complexes 1 and 3-5; this is attributed to a decrease of the intermolecular interactions. Multilayered organic light-emitting diodes (OLEDs) were fabricated by using three (2, 3 and 4) of these IrIII derivatives as dopant materials. The electroluminescence (EL) spectra of the devices, which have the maximum peaks at 509-522 nm, with shoulder peaks near 552 nm, are consistent with the PL spectra in solution at 298 K. The devices show operating voltages at 1 mA/cm 2 of 4,9, 5.6, 5,1, and 4.6 V for Ir(ppy)3, 2, 3, and 4, respectively. In particular, the device with 2 shows a higher external quantum efficiency (etaext = 11% at 1 mA/cm2) and brightness (4543 cd/m2 at 20 mA/cm2) than Ir(ppy)3 (etaext = 6.0% at 1 mA/cm2; 3156 cd/m2 at 20 mA/cm2) and other Ir(dmppy)3 derivatives, (dmppy = dimethyl-substituted ppy), under the same conditions. The methyl groups at the meta (Ph) and para (Py) positions to the Ir metal atom have a great influence on absorption, emission, redox potentials and electroluminescence. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

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Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Electric Literature of 16858-01-8, 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. 16858-01-8, Name is Tris(2-pyridylmethyl)amine, molecular formula is C18H18N4. In a Review£¬once mentioned of 16858-01-8

The versatile ruthenium(II/III) tetraazamacrocycle complexes and their nitrosyl derivatives

Macrocyclic ligands are relevant because of the properties they impart to transition metal complexes, such as enhanced thermodynamic stability and slowed substitution kinetic behavior. Here, we address issues not previously reviewed, revisit others, present new results, and review and discuss the results obtained in the last decade for ruthenium(II/III) complexes with tetraazamacrocycles (mac) such as cyclam (1,4,8,11-tetraazacyclotetradecane), [RuL1L2(mac)]q+ with emphasis on nitrosyls. Topics include synthesis, macrocycle functionalization, structure, spectroscopy, photochemistry, reactivity, density functional theory calculations, and biological properties. [RuL1L2(mac)]q+ complexes exhibit a rich chemistry, sometimes unusual, which depends on macrocycle ring size, the presence of N- or C-pendant groups, metal oxidation state, electronic structure, and the nature of L1 and L2. These same features can be used to tune the properties of the complexes leading to potential applications in diverse fields.

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Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Electric Literature of 76089-77-5, The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.76089-77-5, Name is Cerium(III) trifluoromethanesulfonate, molecular formula is C3CeF9O9S3. In a Article£¬once mentioned of 76089-77-5

Controlled hydrolysis of lanthanide complexes of the N-donor tripod tris(2-pyridylmethyl)amine versus bisligand complex formation

The reaction of the lanthanide salts LnI3(thf)4 and Ln(OTf)3 with tris(2-pyridylmethyl)amine (tpa) was studied in rigorously anhydrous conditions and in the presence of water. Under rigorously anhydrous conditions the successive formation of mono- and bis(tpa) complexes was observed on addition of 1 and 2 equiv of ligand, respectively. Addition of a third ligand equivalent did not yield additional complexes. The mono(tpa) complex [Ce(tpa)l3] (1) and the bis(tpa) complexes [Ln(tpa) 2]X3 (X = I, Ln = La(III) (2), Ln = Ce(III) (3), Ln = Nd(III) (4), Ln = Lu(III) (5); X = OTf, Ln = Eu(III) (6)) were isolated under rigorously anhydrous conditions and their solid-state and solution structures determined. In the presence of water, 1H NMR spectroscopy and ES-MS show that the successive addition of 1-3 equiv of tpa to triflate or iodide salts of the lanthanides results in the formation of mono(tpa) aqua complexes followed by formation of protonated tpa and hydroxo complexes. The solid-state structures of the complexes [Eu(tpa)(H2O)2(OTf) 3] (7), [Eu(tpa)(mu-OH)(OTf)2]2 (8), and [Ce(tpa)(mu-OH)(MeCN)(H2O]2I4 (9) have been determined. The reaction of the bis(tpa) lanthanide complexes with stoichiometric amounts of water yields a facile synthetic route to a family of discrete dimeric hydroxide-bridged lanthanide complexes prepared in a controlled manner. The suggested mechanism for this reaction involves the displacement of one tpa ligand by two water molecules to form the mono(tpa) complex, which subsequently reacts with the noncoordinated tpa to form the dimeric hydroxo species.

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Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI

Related Products of 1941-30-6, 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. 1941-30-6, Name is Tetrapropylammonium bromide, molecular formula is C12H28BrN. In a Article£¬once mentioned of 1941-30-6

Oxidative extraction of thiophene from n-dodecane over TS-1 in continuous process: A model for non-severe sulfur removal from liquid fuels

Liquid phase oxidation of thiophene in dodecane and subsequently extraction of the oxidized product into a polar solvent were studied in continuous process, as a model for selective removal of sulfur-containing compounds from liquid hydrocarbons under a non-severe condition. Titanium silicalite-1 (TS-1) and 30% of H2O2 were used as catalyst and oxidizing agent, respectively. The reactions were carried out at room temperature and 60 C at atmospheric pressure. TS-1 was synthesized, calcined at 550 C and characterized by XRD, ICP-AES, SEM, BET and FT-IR. The continuous stirred tank reactor (CSTR, ?150 ml) was used for the oxidative extraction in the continuous process. Thiophene (1000, 3000 ppm) in dodecane and H2O2 (1.5 %w) in methanol were fed (10-25 ml/h) by a peristaltic pump into the CSTR (150 ml) containing TS-1 (1.0 and 1.8 g). The use of TS-1 catalyst significantly improves rate of thiophene removal as the oxidized products SO4- species) can be transferred to the solvent, readily faster than the simple thiophene extraction. The reaction using methanol as a solvent showed a higher efficiency of thiophene removal, as compared to that using acetonitrile, acetic acid and water, respectively. The oxidation activity was increased when the solvent/oil ratio was increased. Increasing amounts of catalyst and decreasing feeding rate lead to an increase in oxidative extraction of thiophene. The deactivation of the catalyst is due to the titanium leaching and this can be improved when the calcinations temperature was raised.

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Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI