369-57-3Relevant articles and documents
Effects of surface monolayers on the electron-transfer kinetics and adsorption of methyl viologen and phenothiazine derivatives on glassy carbon electrodes
Yang, Hseuh-Hui,McCreery
, p. 4081 - 4087 (1999)
Five organic redox systems were examined in aqueous electrolytes on polished and chemically modified glassy carbon (GC), to evaluate the effects of surface structure on the heterogeneous transfer rate constant, k°. Methyl viologen reduction to its cation radical exhibited a voltammetric peak potential difference which was insensitive to surface modification, with k°decreasing by only 50% when a chemisorbed monolayer was present. Methylene blue and three other phenothiazines adsorbed to polished GC, but the adsorption was suppressed by surface modification. For all four phenothiazines, chemisorbed or physisorbed monolayers of electroinactive species had minor effects on k°, with a compact nitrophenyl monolayer decreasing k°by 50%. This minor change in k°was accompanied by a major decrease in adsorption, apparently due to inhibition of dipole-dipole or π- π interactions between the phenothiazine and GC. Chlorpromazine oxidation to its cation radical was studied in more detail, under conditions where adsorption was suppressed. A plot of the natural log of the observed rate constant vs the monolayer thickness for a variety of chemisorbed monolayers was linear, with a slope of -0.22 A-1. The observations are consistent with a through-bond electron-tunneling mechanism for electron transfer to all five redox systems studied. The tunneling constant for CPZ of 0.22 A-1 is between that reported for electron tunneling through conjugated polyene spacers (0.14 A-1) and that reported for phenyl-methylene spacers (0.57 A-1), on the basis of long-range electron transfer in rigid molecules.
Irreversible tautomerization as a powerful tool to access unprecedented functional porous organic polymers with a tris(β-keto-hydrazo)cyclohexane subunit (TKH-POPs)
Liu, Xiangxiang,Luo, Xian-Sheng,Fu, Hao-Xi,Fan, Wenhao,Chen, Shi-Lu,Huang, Mu-Hua
, p. 2103 - 2106 (2020)
Porous organic polymers (POPs) have received much attention, due to their multiple potential applications and flexibility in chemical structure design. Creation of a novel chemical structure has been the central task in the research of POPs, which are usually constructed by direct coupling polymerizations. The fascinating rearrangement/tautomerization could lead to some novel structures, which are hard to access by conventional direct coupling polymerizations. Herein, the tautomerization from tris(β-hydroxyl-azo)benzene to the tris(β-keto-hydrozo)cyclohexane structure has been proved unambiguously based on an advanced 2D NMR technique such as 15N-1H-HSQC and 1H-1H-NOESY. The crucial tautomerization was used to synthesize TKH-POPs for the first time. The as-synthesized TKH-POP-1 was found to have an adsorption capacity as high as 66.3 mmol g-1 (at 273 K and P/P0 = 0.98) towards acetonitrile vapor, which was the highest among all the reported materials. The general and flexible strategy to make functional POPs with tunable pores such as ultramicropores, micropores and mesopores will help develop interesting functional POPs in the near future.
Aqueous and Visible-Light-Promoted C-H (Hetero)arylation of Uracil Derivatives with Diazoniums
Liu, An-Di,Wang, Zhao-Li,Liu, Li,Cheng, Liang
, p. 16434 - 16447 (2021/11/16)
Direct C5 (hetero)arylation of uracil and uridine substrates with (hetero)aryl diazonium salts under photoredox catalysis with blue light was reported. The coupling proceeds efficiently with diazonium salts and heterocycles in good functional group tolerance at room temperature in aqueous solution without transition-metal components. A plausible radical mechanism has been proposed.
Metal-Free Visible-Light Synthesis of Arylsulfonyl Fluorides: Scope and Mechanism
Louvel, Dan,Chelagha, Aida,Rouillon, Jean,Payard, Pierre-Adrien,Khrouz, Lhoussain,Monnereau, Cyrille,Tlili, Anis
supporting information, p. 8704 - 8708 (2021/05/17)
The first metal-free procedure for the synthesis of arylsulfonyl fluorides is reported. Under organo-photoredox conditions, aryl diazonium salts react with a readily available SO2 source (DABSO) to afford the desired product through simple nucleophilic fluorination. The reaction tolerates the presence of both electron-rich and -poor aryls and demonstrated a broad functional group tolerance. To shed the light on the reaction mechanism, several experimental techniques were combined, including fluorescence, NMR, and EPR spectroscopy as well as DFT calculations.