14187-32-7, Name is Dibenzo-18-crown-6, molecular formula is C20H24O6, belongs to chiral-catalyst compound, is a common compound. In a patnet, once mentioned the new application about 14187-32-7, SDS of cas: 14187-32-7
Definitive X-ray structures of “separated” versus “contact” ion pairs, together with their spectral (UV-NIR, ESR) characterizations, provide the quantitative basis for evaluating the complex equilibria and intrinsic (self-exchange) electron-transfer rates for the potassium salts of p-dinitrobenzene radical anion (DNB-). Three principal types of ion pairs, K(L)+DNB-, are designated as Classes S, M, and C via the specific ligation of K+ with different macrocyclic polyether ligands (L). For Class S, the self-exchange rate constant for the separated ion pair (SIP) is essentially the same as that of the “free” anion, and we conclude that dinitrobenzenide reactivity is unaffected when the interionic distance in the separated ion pair is r SIP ? 6 A. For Class M, the dynamic equilibrium between the contact ion pair (with rCIP = 2.7 A) and its separated ion pair is quantitatively evaluated, and the rather minor fraction of SIP is nonetheless the principal contributor to the overall electron-transfer kinetics. For Class C, the SIP rate is limited by the slow rate of CIP ? SIP interconversion, and the self-exchange proceeds via the contact ion pair by default. Theoretically, the electron-transfer rate constant for the separated ion pair is well-accommodated by the Marcus/Sutin two-state formulation when the precursor in Scheme 2 is identified as the “separated” inner-sphere complex (ISSIP) of cofacial DNB-/DNB dyads. By contrast, the significantly slower rate of self-exchange via the contact ion pair requires an associative mechanism (Scheme 3) in which the electron-transfer rate is strongly governed by cationic mobility of K(L)+ within the “contact” precursor complex (ISCIP) according to the kinetics in Scheme 4.
Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.SDS of cas: 14187-32-7. In my other articles, you can also check out more blogs about 14187-32-7