4381-14-0Relevant articles and documents
CIDNP and CIDEP Studies on Intramolecular Hydrogen Abstraction Reaction of Polymethylene-Linked Xanthone and Xanthene. Determination of the Exchange Integral of the Intermediate Biradicals
Maeda, Kiminori,Terazima, Masahide,Azumi, Tohru,Tanimoto, Yoshifumi
, p. 197 - 204 (1991)
Hydrogen abstraction reaction of a polymethylene-linked system is investigated by using chemically induced dynamic nuclear and electron polarization (CIDNP and CIDEP) methods.The reaction scheme is determined from the CIDNP and CIDEP spectra of the unlinked xanthene and xanthone system.The exchange integral J between the two terminal radicals of the system is obtained from the simulation process by using the spin-correlated CIDEP theory modified with (a) the fast population relaxation between the central S-T0 mixed states, (b) the contribution from the triplet mechanism, and (c) hyperfine line dependent line width.The mechanism of the fast population relaxation and the dependence of the J value on the temperature and polymethylene chain length are discussed.
Oxidation of alcohols and activated alkanes with lewis acid-activated tempo
Nguyen, Thuy-Ai D.,Wright, Ashley M.,Page, Joshua S.,Wu, Guang,Hayton, Trevor W.
, p. 11377 - 11387 (2015/02/19)
The reactivity of MCl3(η1O) (M = Fe, 1; Al, 2; TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) with a variety of alcohols, including 3,4-dimethoxybenzyl alcohol, 1-phenyl-2-phenoxyethanol, and 1,2-diphenyl-2-methoxyethanol, was investigated using NMR spectroscopy and mass spectrometry. Complex 1 was effective in cleanly converting these substrates to the corresponding aldehyde or ketone. Complex 2 was also able to oxidize these substrates; however, in a few instances the products of overoxidation were also observed. Oxidation of activated alkanes, such as xanthene, by 1 or 2 suggests that the reactions proceed via an initial 1-electron concerted proton-electron transfer (CPET) event. Finally, reaction of TEMPO with FeBr3 in Et2O results in the formation of a mixture of FeBr3(η1OH) (23) and [FeBr2(η1OH)]2(μ-O) (24), via oxidation of the solvent, Et2O.
A high-valent iron-oxo corrolazine activates C-H bonds via hydrogen-atom transfer
Cho, Kevin,Leeladee, Pannee,McGown, Amanda J.,Debeer, Serena,Goldberg, David P.
experimental part, p. 7392 - 7399 (2012/06/16)
Oxidation of the FeIII complex (TBP8Cz)Fe III [TBP8Cz = octakis(4-tert-butylphenyl)corrolazinate] with O-atom transfer oxidants under a variety of conditions gives the reactive high-valent Fe(O) complex (TBP8Cz+?)Fe IV(O) (2). The solution state structure of 2 was characterized by XAS [d(Fe-O) = 1.64 A]. This complex is competent to oxidize a range of C-H substrates. Product analyses and kinetic data show that these reactions occur via rate-determining hydrogen-atom transfer (HAT), with a linear correlation for log k versus BDE(C-H), and the following activation parameters for xanthene (Xn) substrate: ΔH? = 12.7 ± 0.8 kcal mol -1, ΔS? = -9 ± 3 cal K-1 mol-1, and KIE = 5.7. Rebound hydroxylation versus radical dimerization for Xn is favored by lowering the reaction temperature. These findings provide insights into the factors that control the intrinsic reactivity of Compound I heme analogues.