Electric Literature of 21797-13-7, 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, 21797-13-7, molcular formula is C8H12B2F8N4Pd, introducing its new discovery.
Mechanistic Studies on Cyclopalladation of the Solvated Palladium (II) Complexes with N-Benzyl Triamine Ligands in Various Solvents. Crystal Structures of [Pd(Sol)(Bn2Medptn)](BF4)2 (Sol = Acetonitrile and N, N-Dimethylformamide; Bn2Medptn = N, N?-Dibenzyl-4-methyl-4-azaheptane-1,7-diamine) and [Pd(H-1Bn2Medptn-C, N
Several solvated palladium(II) complexes with the potentially cyclopulladating dibenzyl ligand have been synthesized. These include [Pd(CH3CN)(Bn2Medptn)](BF4)2 (1) (Bn2Medptn = N, N’-dibenzyl-4-methyl-4-azaheptane-1,7-diamine), [Pd(dmf)(Bn2Medptn)](BF4)2 (2) (dmf = N, N-dimethylformamide), and [Pd(dmso)(Bn2Medptn)](BF4)2 (3) (dmso = dimethyl sulfoxide), their cyclopalladated complex, [Pd(H-1Bn2Medptn-C, N, N’, N”)]CF3SO3 (4), the solvated monobenzyl complex, [Pd(CH3CN)(BnMedptn)](BF4)2 (5) (BnMedptn = N-(3-aminopropyl)-N’-benzyl-N-methyl-1,3-propanediamine), and its deuterated complex, [Pd(CH3CN)(BnMedptn-d7)](BF4)2 (6) (BnMedptn-d7 = N-(3-aminopropyl)-N’-heptadeuteriobenzyl-N-methyl-1,3-propanediamine). The crystal structures of 1¡¤CH3CN¡¤CH2Cl2, 2, and 4 have been determined by X-ray structure analysis to characterize the reactant and the product for the cyclopalladation of the solvated complexes, where one of the ortho carbons of 1 is directed toward the palladium(II) center (Pd¡¤¡¤¡¤C(1) = 3.513(9) A). The rate constants for the cyclopalladation of 1 at 25C in various solvents increase in the order DMF < DMSO?pyridine, but the reaction does not proceed in acetonitrile or nitromethane. The activation parameters for the cyclopalladation in neat solvent have been obtained as follows: k298 = 5.74 ¡Á 10-6, DeltaH? = 104.0¡À1.2kJmol-1 and DeltaS? = 3.5¡À3.9 JK-1 mol-1 for 1 in DMF, k298 = 3.13 ¡Á 10-4 s-1, DeltaH? = 83.8¡À2.6 kJ mol-1 and DeltaS? = -31.0¡À8.8 JK-1 mol-1 for 1 in DMSO, k298 = 1.30¡Á10-4 s-1, DeltaH? = 81.2¡À0.5 kJ mol-1 and DeltaS? = -47.0¡À1.8 J K-1 mol-1 for 5 in DMF, k298 = 1.76¡Á10-3 s-1 for 5 in DMSO, k298 = 1.26¡Á10-5 s-1, DeltaH? = 92.8¡À1.4 kJ mol-1 and DeltaS? = -27.5¡À4.4 J K-1 mol-1 for 6 in DMF and k298 = 2.69¡Á10-4 s-1 for 6 in DMSO. The activation enthalpy is reduced as the solvent basicity increases. The kinetic isotope effects (kH/kD) for the cyclopalladation of the monobenzyl complex at 25C are calculated to be 10.3 in DMF and 6.5 in DMSO using the rate constants for 5 and 6. It is confirmed from the kinetic results obtained that the nucleophilic attack of the basic solvent on the ortho proton is essential for the C-H bond cleavage observed in the activation process. In addition, the fact that the rate constant for the cyclopalladation is proportionally dependent on the concentration of DMSO in nitromethane strongly suggests that the solvent-dissociation pre-equilibrium is negligible in neat basic solvent. The proportionality constant is the rate constant for the particular unimolecular reaction. the reaction rate is directly proportional to the concentration of the reactant. I hope my blog about 21797-13-7 is helpful to your research. Electric Literature of 21797-13-7
Reference£º
Chapter 1 An introduction to palladium catalysis,
Palladium/carbon catalyst regeneration and mechanical application method