58478-75-4Relevant articles and documents
Donor-Acceptor (Electronic) Coupling in the Precursor Complex to Organic Electron Transfer: Intermolecular and Intramolecular Self-Exchange between Phenothiazine Redox Centers
Sun, Duoli,Rosokha, Sergiy V.,Kochi, Jay K.
, p. 1388 - 1401 (2004)
Intermolecular electron transfer (ET) between the free phenothiazine donor (PH) and its cation radical (PH.+) proceeds via the [1:1] precursor complex (PH)2.+ which is transiently observed for the first time by its diagnostic (charge-resonance) absorption band in the near-IR region. Similar intervalence (optical) transitions are also observed in mixed-valence cation radicals with the generic representation: P(br)P .+, in which two phenothiazine redox centers are interlinked by p-phenylene, o-xylylene, and o-phenylene (br) bridges. Mulliken-Hush analysis of the intervalence (charge-resonance) bands afford reliable values of the electronic coupling element HIV based on the separation parameters for (P/P.+) centers estimated from some X-ray structures of the intermolecular (PH)2.+ and the intramolecular P(br)P .+ systems. The values of HIV, together with the reorganization energies λ derived from the intervalence transitions, yield activation barriers ΔGET? and first-order rate constants kET for electron-transfer based on the Marcus-Hush (two-state) formalism. Such theoretically based values of the intrinsic barrier and ET rate constants agree with the experimental activation barrier (E a) and the self-exchange rate constant (kSE) independently determined by ESR line broadening measurements. This convergence validates the use of the two-state model to adequately evaluate the critical electronic coupling elements between (P/P.+) redox centers in both (a) intermolecular ET via the precursor complex and (b) intramolecular ET within bridged mixed-valence cation radicals. Important to intermolecular ET mechanism is the intervention of the strongly coupled precursor complex since it leads to electron-transfer rates of self-exchange that are 2 orders of magnitude faster (and activation barrier that is substantially lower) than otherwise predicted solely on the basis of Marcus reorganization energy.
Transition-Metal-Free and Base-Promoted Carbon-Heteroatom Bond Formation via C-N Cleavage of Benzyl Ammonium Salts
Liu, Long,Tang, Yuanyuan,Wang, Kunyu,Huang, Tianzeng,Chen, Tieqiao
, p. 4159 - 4170 (2021/03/09)
A facile and general method for constructing carbon-heteroatom (C-P, C-O, C-S, and C-N) bonds via C-N cleavage of benzyl ammonium salts under transition-metal-free conditions was reported. The combination of t-BuOK and 18-crown-6 enabled a wide range of substituted benzyl ammonium salts to couple readily with different kinds of heteroatom nucleophiles, i.e. hydrogen phosphoryl compounds, alcohols, thiols, and amines. Good functional group tolerance was demonstrated. The scale-up reaction and one-pot synthesis were also successfully performed.
Pd-Catalyzed double N-arylation of primary amines to synthesize phenoxazines and phenothiazines
Zhang, Lu,Huang, Xin,Zhen, Shan,Zhao, Jing,Li, Heng,Yuan, Bingxin,Yang, Guanyu
, p. 6306 - 6309 (2017/08/10)
An efficient and versatile Pd-catalyzed tandem C-N bond formation between aryl halides and primary amines is developed. The transformation allows a one-pot synthesis of phenoxazine and phenothiazine derivatives with a broad range of substitution patterns from readily available precursors.
An efficient ultrasound-assisted synthesis of n-alkyl derivatives of carbazole, indole, and phenothiazine
Zhao, Sanhu,Kang, Jin,Du, Yuting,Kang, Jingyan,Zhao, Xiaoni,Xu, Yinfeng,Chen, Ruixi,Wang, Qianqian,Shi, Xitao
supporting information, p. 683 - 689 (2014/06/10)
Heterocyclic compounds bearing an acidic hydrogen atom attached to nitrogen such as carbazole, indole, and phenothiazine can be efficiently alkylated in DMSO or N,N-DMF under ultrasonic irradiation in the presence of potassium hydroxide as a base. In almost all cases, a dramatic reduction of the reaction time results and a clear yield increase accompanied by an improved quality of the products occurs.
