Tag: M.W:300-400

Reference of 14187-32-7, 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. 14187-32-7, C20H24O6. A document type is Article, introducing its new discovery.

The Solvent Extraction Study of a Dibenzo-18-crown-6 Complex with Silver Picrate

The extraction constant of the silver ion-dibenzo-18-crown-6 (DB18C6) complex between benzene and water and the complex-formation constant of DB18C6 with silver picrate in benzene were determined at 25 deg C.The Ag+-DB18C6 complex is much more extractable than the Ag+-18-crown-6 one.The Ag+-DB18C6 complex is much more stable for benzene than for aqueous solutions.

If you are hungry for even more, make sure to check my other article about 14187-32-7. Reference of 14187-32-7

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

Application of 14187-32-7, An article , which mentions 14187-32-7, molecular formula is C20H24O6. The compound – Dibenzo-18-crown-6 played an important role in people’s production and life.

Pseudorotaxane based on tetraazamacrocyclic copper complex and dibenzocrown ether

Host-guest interactions between two electron-rich dibenzocrown ethers and electron deficient macrocyclic copper(ii) tetraimine complexes lead to the formation of pseudorotaxane in solution. The interactions are enhanced with the copper(iii) complex compared to that of the copper(ii) form as shown by the electrochemical studies. The larger – 30-membered dibenzocrown donor interacted with the copper complex stronger than the smaller ones as revealed by NMR and electrochemical methods. The thiolated form of the copper(ii) tetraimine complex was self-assembled at the gold electrode forming an electroactive monolayer able to interact with the crown ether in the solution. These donor-acceptor interactions lead to an increase of the barrier properties of the layer and decreased the electron transfer rate between the copper centre and the gold electrode surface as proved by the voltammetric data.

I hope this article can help some friends in scientific research. I am very proud of our efforts over the past few months and hope to 14187-32-7, help many people in the next few years., Application of 14187-32-7

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

Synthetic Route of 14187-32-7, 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. 14187-32-7, C20H24O6. A document type is Article, introducing its new discovery.

Synthesis, crystal structure and NMR of [Na(DB18C6)(CH3CN)] 3[alpha-AsM12O40] (M = Mo/W)

Two super-molecular complexes [Na(DB18C6)(CH3CN)] 3[alpha-AsM12O40] (M = Mo/W) were obtained by solvothermal reaction and characterized by IR,1H 13C and gUMBC NMR, X-ray. The result reveals that the complex consists of a [alpha-AsM12O40]3- (M = Mo/W) anion with alpha-Keggin structure, and three complex [Na (DB18C6)(CH3CN)] + cations in which every sodium ion is located in the cavity of dibenzo-18-crown-6 with 6 Na-O bonds and coordinated with one of the terminal O atom of [alpha-AsM12O40]3- (M = Mo/W) and the N atom of CH3CN from two sides of the distorted DB18C6 plane, respectively. The three terminal O atoms linked with sodium ion are from a single M3O13 (M = Mo/W) triplet of the alpha-Keggin metalatoarsenate anion, and M-Ob (M = Mo/W) bonds exhibit alternating single-double bond character.

If you are hungry for even more, make sure to check my other article about 14187-32-7. Synthetic Route of 14187-32-7

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

Application of 14187-32-7. Let¡¯s face it, organic chemistry can seem difficult to learn. Especially from a beginner¡¯s point of view. Like 14187-32-7, Name is Dibenzo-18-crown-6. In a document type is Conference Paper, introducing its new discovery.

Synthesis, crystal structure and NMR of [Na(DB18C6)(CH3CN)] 3[alpha-PW12O40]

A novel super-molecular complex [Na(DB18C6)(CH3CN)]3 [alpha-PW12O40] was obtained by solvothermal reaction and characterized by IR, X-ray, 1H, 13C and 31P NMR. The result reveals that the complex consists of an [alpha-PW 12O40]3- anion with alpha-Keggin structure and three complex [Na(DB18C6)(CH3OH)]+ cations in which every sodium ion located in the cavity of dibenzo-18-crown-6 with six Na-O bonds and coordinated with one of the terminal O atom of [alpha-PW 12O40]3- and the N atom of CH3CN from two sides of the distorted DB18C6 plane, respectively. The three terminal O atoms linked with sodium ion are from a single W3O3 triplet of the alpha-Keggin tungstophosphate anion. The 13C resonance (119.27 ppm) bonded to N atom in CH3CN has been clarified by gUMBC spectrum (see Fig. 1), which is too weak to be observed in 13C NMR spectrum due to its too low relaxation rate.

If you are interested in 14187-32-7, you can contact me at any time and look forward to more communication.Application of 14187-32-7

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.185449-80-3, Name is (S)-N,N-Dimethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine, molecular formula is C22H18NO2P. In a Article£¬once mentioned of 185449-80-3, Computed Properties of C22H18NO2P

Enantioselective Synthesis of Axially Chiral Biaryls via Cu-Catalyzed Acyloxylation of Cyclic Diaryliodonium Salts

We report here a Cu-catalyzed enantioselective acyloxylation of cyclic diaryliodonium salts. With readily available cyclic diaryliodonium salts and ubiquitous aliphatic or (hetero)aromatic carboxylic acids as the starting materials, various axially chiral acyloxylated 2-iodobiaryls were prepared in excellent yield and with excellent enantioselectivity (mostly 99% yield and 99% ee). Density functional theory calculations were conducted to reveal the stereo- and regioselectivities. This simple reaction protocol can be employed for the late-stage modification of some drug molecules. Finally, by diversity-oriented transformations, these acyloxylated 2-iodobiaryl products can be easily transformed into diverse valuable functionalized biaryls that could be used as chiral ligands or functional materials.

Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.Computed Properties of C22H18NO2P, you can also check out more blogs about185449-80-3

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

Reference of 14187-32-7. Chemistry is an experimental science, and the best way to enjoy it and learn about it is performing experiments.Introducing a new discovery about 14187-32-7, Name is Dibenzo-18-crown-6

Mechanism of Complexation of Crown Ethers as a Function of Alkali Ions and the Rigidity of the Ligands

The kinetics of complexation of Na+ and K+ with the crown ethers dicyclohexano-18-crown-6 (DH18C6) and dibenzo-18-crown-6 (DB18C6) in the solvent dimethylformamide (DMF) and Na+ with DH18C6 in methanol (MeOH) have been studied by ultrasonic relaxation techniques in the frequency range from <*>1 to <*>400 MHz.The results are compared with data for the same cations reacting with 18-crown-6 (18C6).In DMF at 40 deg C for Na+ added to DH18C6 in molar ratio R <*> 1 two relaxation processes apper that are displaced within a factor of two in relaxation frequencies from those of the system Na+ = 18C6.For K+ added to DH18C6 (R=1) two relaxation processes appear at about the same frequency as for the system K+ + 18C6.The difference between the results for Na+ and K+ may reflect the closer fit of the potassium cation radius with the macrocycle cavyty.For Na+ + DB18C6 in DMF at 40 deg C two relaxation processes, the first at about the same frequency as for DH18C6 but the second below 1 MHz, are detectable.For K+ + DB18C6 in DMF at 40 deg C, both relaxation frequencies are dramatically shifted with the lower one lying below 1 MHz.The behavior of the process at lower frequency is compatible with the progressive increase of ligand ring rigidity in going from 18C6 to DH18C6 and to DB18C6, if the rate-determining factor of the process at the lower frequency is attributed to the encirclement of the metal cation by the ligand.In MeOH the surmise that the ligand rearrangement also plays a role in the reaction coordinate energy profile of the complexation of alkali metal cations added to 18C6 is supported by new data now available with the resonator technique, the data revealing two relaxation processes for both Li+ and Na+.In MeOH, the system Na+ + DH18C6 gives rise to two detectable relaxation processes at 25 deg C.Surprisingly, they are a factor of two faster than for the system Na+ + 18C6 (at variance with the same system in DMF solvent).For Li+ + DH18C6 in MeOH from the only run available it appears that the process at high frequency is somewhat faster than for Li+ + 18C6 in MeOH whereas the one at low frequency is lower by a factor of 3 or more with respect to the one in the system Li+ + 18C6.This complex behavior may indicate a concerted process in which both the solvent substitution and ligand rearrangement influence the energy profile of the overall process.In the majority of cases the activation parameters have been evaluated from the temperature dependence of the relaxation processes.

If you are hungry for even more, make sure to check my other article about 14187-32-7. Reference of 14187-32-7

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.14187-32-7, Name is Dibenzo-18-crown-6, molecular formula is C20H24O6. In a Article£¬once mentioned of 14187-32-7, Formula: C20H24O6

Second-sphere Co-ordination of Cationic Rhodium Complexes (Rh(L)(NH3)2)+ by Dibenzo-3n-crown-n Ethers . Solution 1H Nuclear Magnetic Resonance Spectroscopic Studies and X-Ray Crystal Structures

Cationic rhodium(1) complexes of the form are solubilised in halocarbon solvents by the addition of equimolar quantities of crown ethers such as 18-crown-6 (18-c-6) or dibenzo-3n-crown-n (n=6-12) ethers (db-3n-c-n).Solubilisation is a result of the formation of stable, highly structured, second-sphere co-ordination complexes in which a macrocyclic polyether interacts with the ammine ligands on rhodium via multiple hydrogen-bond formation. 1H N.m.r. spectroscopic investigations in CD2Cl2 show that the resonances of protons associated with the diene ligands (L) undergo significant upfield shifts (Deltadelta values of up to 0.75 p.p.m.) when certain of the db-3n-c-n ethers (n=7-10) are used in preference to 18-c-6, suggesting that the dienes are experiencing anisotropic ring-current shielding by the crown ether benzo rings.The close proximity of co-ordinated diene and db-3n-c-n ether aromatic rings, which this shielding requires, is confirmed by single-crystal X-ray studies of the isolated 1:1 adducts. (Rh(cod)(NH3)2.db-21-c-7> is monoclinic, space group P21/c,a=9.121(1), b=23.405(2), c=16.705(3) Angstroem, beta=96.30(1) deg, Z=4, R=0.047. is monoclinic, P21/c,a=9.195(3), b=29.380(9), c=13.900(6) Angstroem, beta=93.04(3) deg, Z=4, R=0.043. is monoclinic, P21/c,a=9.268(2), b=34.335(7), c=13.421(3) Angstroem, b=93.92(2) deg, Z=4, R=0.034. is orthorombic, Pbca,a=15.427(3), b=18.739(3), c=25.458(5) Angstroem, Z=8, R=0.047.In all these supramolecular structures the crown ether adopts a V-shaped conformation with the ammine ligands forming hydrogen bonds to ether oxygens and with the co-ordinated diene sandwiched between the benzo rings of the db-3n-c-n ethers.In the addition to electrostatic stabilisation, there are also a large number of other longer range contacts (C…H, Rh…C, Rh…O) at about van der Waals’ distances which probably make a small contribution to the binding energy and possibly help to define the structures of the adducts.In contrast to the 1:1 adducts, the 2:1 adduct, <2.db-36-c-12>2 (triclinic, P1*, a=9.020(2), b=12.241(3), c=14.196(3) Angstroem, alpha=100.20(2), beta=99.00(2), gamma=98.11(2) deg, Z=1, R=0.040) has a relatively flat structure in which a complex ion is hydrogen bonded to each face of the crown ether.

Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.Formula: C20H24O6, you can also check out more blogs about14187-32-7

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

Synthetic Route of 185449-80-3. Chemistry is an experimental science, and the best way to enjoy it and learn about it is performing experiments.Introducing a new discovery about 185449-80-3, Name is (S)-N,N-Dimethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine

Nonlinear effects in the enantioselective 1,4-conjugate addition of diethylzinc to chalcone

A clear positive nonlinear effect of the enantiopurity of ligand 1 on the product ee was observed in the enantioselective 1,4-conjugate addition of Et2Zn to chalcone. The experimental data of nonlinear effect meet Kagan’s ML2 model.

If you are hungry for even more, make sure to check my other article about 185449-80-3. Synthetic Route of 185449-80-3

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

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. 39648-67-4, C20H13O4P. A document type is Article, introducing its new discovery., Application In Synthesis of (R)-4-Hydroxydinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide

Asymmetric synthesis of tetrahydro-beta-carbolines via chiral phosphoric acid catalyzed transfer hydrogenation reaction

Chiral phosphoric acid catalyzed enantioselective transfer hydrogenation of hydroxylactams has been realized to provide enantioenriched tetrahydro-beta-carbolines in dioxane at room temperature (up to 94% yield, 90% ee).

Interested yet? Keep reading other articles of 39648-67-4!, Application In Synthesis of (R)-4-Hydroxydinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare

 

39648-67-4, Name is (R)-4-Hydroxydinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, molecular formula is C20H13O4P, belongs to chiral-catalyst compound, is a common compound. In a patnet, once mentioned the new application about 39648-67-4, Safety of (R)-4-Hydroxydinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide

Catalytic asymmetric Povarov reaction of isatin-derived 2-azadienes with 3-vinylindoles

The first catalytic asymmetric Povarov reaction of isatin-derived 2-azadienes with 3-vinylindoles was established in the presence of chiral phosphoric acid, which tolerates a wide range of substrates with generally excellent diastereoselectivity and good enantioselectivity (up to >95:5 dr, 89:11 er). This approach will greatly enrich the chemistry of the catalytic asymmetric Povarov reaction, in particular ketone-involved transformations. Furthermore, this protocol represents the first diastereo- and enantio-selective construction of a spiro[indolin-3,2?-quinoline] framework bearing an indole moiety. This novel type of spiro-compound not only contains two chiral centers, including one quaternary stereogenic center, but also integrates two biologically important structures of spiro[indolin-3,2?-quinoline] and indole, which may find medicinal applications after bioassay.

Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.Safety of (R)-4-Hydroxydinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide. In my other articles, you can also check out more blogs about 39648-67-4

Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare