Two-Step Synthesis,Structure, and Optical Features of a Double Hetero[7]helicene

A novel double aza-oxa[7]helicene was synthesized from the commercially available N¹,N⁴-di(naphthalen-2-yl)benzene-1,4-diamine and p-benzoquinone in two steps. Combining the acid-mediated annulation with the electrochemical sequential reaction (oxidative coupling and dehydrative cyclization) afforded this double hetero[7]helicene. Moreover, the structural and optical features of this molecule have been studied using X-ray crystallographic analysis, and the absorption and emission behaviors were rationalized based on DFT calculations.     

Revisiting Alkane Hydroxylation with m-CPBA (m-Chloroperbenzoic Acid) Catalyzed by Nickel(II) Complexes

Mechanistic studies are performed on the alkane hydroxylation with m-CPBA (m-chloroperbenzoic acid) catalyzed by nickel(II) complexes, Ni^II(L). In the oxidation of cycloalkanes, Ni^II(TPA) acts as an efficient catalyst with a high yield and a high alcohol selectivity. In the oxidation of adamantane, the tertiary carbon is predominantly oxidized. The reaction rate shows first-order dependence on [substrate] and [Ni^II(L)] but is independent on [m-CPBA]; v_obs=k₂[substrate][Ni^II(L)]. The reaction exhibited a relatively large kinetic deuterium isotope effect (KIE) of 6.7, demonstrating that the hydrogen atom abstraction is involved in the rate-limiting step of the catalytic cycle. Furthermore, Ni^II(L) supported by related tetradentate ligands exhibit apparently different catalytic activity, suggesting contribution of the Ni^II(L) in the catalytic cycle. Based on the kinetic analysis and the significant effects of O₂ and CCl₄ on the product distribution pattern, possible contributions of (L)Ni^II−O^. and the aroyloxyl radical as the reactive oxidants are discussed.     

Synthesis of Tetra-Substituted Trifluoromethyl-3,1-Benzoxazines by Transition-Metal-Catalyzed Decarboxylative Cyclization of N-Benzoyl Benzoxazinones

Efficient synthesis of N,O-heterocyclic tetra-substituted trifluoromethyl-3,1-benzoxazines via a transition-metal-catalyzed decarboxylative intramolecular cyclization was achieved. The decarboxylation of N-benzoyl trifluoromethyl-benzoxazinones generated the amide oxygen nucleophile, allowing a selective internal C₁-attack on Pd- or Cu-coordinated zwitterions, affording medicinally attractive tetra-substituted vinyl- or ethynyl-trifluoromethyl-3,1-benzoxazines. This protocol can be applied to the synthesis of perfluoroalkyl- and non-fluorinated 3,1-benzoxazines.     

Photoswitchable Chiral Organocatalysts: Photocontrol of Enantioselective Reactions

This study presents recent advances in photoswitchable chiral organocatalysts and their applications in the photomodulation of enantioselective reactions. Under irradiation with an appropriate wavelength of light, the E/Z-photoisomerization of the photoresponsive units on the catalysts leads to the control of the catalytic activity and/or selectivity of the enantioselective reactions. Additionally, this study elucidates the design, synthesis, and catalytic application of the fabricated azobenzene BINOL-based photoswitchable chiral phase-transfer catalysts. This account will provide insights into the appropriate design of a photoswitchable chiral organocatalyst that can achieve both good enantioselectivity and photocontrol.     

Influence of ZIF-8 modification on performance of ZnO-based dye-sensitized solar cells

Journal of Solid State Electrochemistry - Metal–organic frameworks (MOFs) were used to modify the surface of nanoparticulate ZnO electrodes, aiming at enhancing the performance of...     

Cover Picture: Electrochemical Method for G-quartet RNA Detection of COVID-19 Based on Cyclic Ferrocenylnaphthalene Diimide (Electroanalysis 4/2023)

To develop an electrochemical detection method for COVID-19, we have investigated the interaction between RG-1, a characteristic parallel four-strand RNA component of the COVID-19 genome, and cyclic ferrocenylnaphthalene diimides carrying different linker lengths 1 and 2 , which bind to RG-1 more strongly than cyclic naphthalene diimide 3 that lacks a ferrocene moiety. In particular, the binding affinity of 1 having short one showed the highest binding affinity to RG-1, and the redox current of 1 increased in the presence of RG-1 using a glassy carbon electrode. This increasing current of 1 in the presence of c-myc as a parallel G4 DNA or single-stranded RNA was lower than that in the presence of RG-1. Several RG-1 was electrochemically detected at the nanomolar level by 1 .