The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.1436-59-5, Name is cis-Cyclohexane-1,2-diamine, molecular formula is C6H14N2. In a Article£¬once mentioned of 1436-59-5, Recommanded Product: cis-Cyclohexane-1,2-diamine
Influence of Electron-Withdrawing Substituents on the Electronic Structure of Oxidized Ni and Cu Salen Complexes
Nickel (Ni(SalCF3)) and copper (Cu(SalCF3)) complexes of an electron-poor salen ligand were prepared, and their one-electron oxidized counterparts were studied using an array of spectroscopic and theoretical methods. The electrochemistry of both complexes exhibited quasi-reversible redox processes at higher potentials in comparison to the M(SalR) (R = tBu, OMe, NMe2) analogues, in line with the electron-withdrawing nature of the para-CF3 substituent. Chemical oxidation, monitored by ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, afforded their corresponding one-electron oxidized products. Ligand-based oxidation was observed for [Ni(SalCF3)]+?, as evidenced by sharp NIR transitions in the UV-vis-NIR spectrum and a broad isotropic signal at g = 2.067 by solution electron paramagnetic resonance (EPR) spectroscopy. Such sharp NIR transitions observed for [Ni(SalCF3)]+? are indicative of a delocalized electronic structure, which is in good agreement with electrochemical measurements and density functional theory (DFT) calculations. In addition, the increased Lewis acidity of [Ni(SalCF3)]+?, evident from the EPR g-value and DFT calculations, was further quantified by the binding affinity of axial ligands to [Ni(SalCF3)]+?. For [Cu(SalCF3)]+, an intense ligand-to-metal charge transfer band at 18 700 cm-1 in the UV-vis-NIR spectrum was observed, which is diagnostic for the formation of a CuIII species [J. Am. Chem. Soc., 2008, 130, 15448-15459]. The CuIII character for [Cu(SalCF3)]+ is further confirmed by 19F NMR analysis. Taken together, these results show that the electron-deficient salen ligand H2SalCF3 increases the Lewis acidity of the coordinating metal center.
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.Recommanded Product: cis-Cyclohexane-1,2-diamine, you can also check out more blogs about1436-59-5
Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare