Catalytic
acceptorless dehydrogenation (CAD) has been a basically
important organic transformation to ubiquitous unsaturated compounds
without the usage of a sacrificial hydrogen acceptor. In this work,
we successfully developed the first electrochemical acceptorless dehydrogenation
(ECAD) of N-heterocycles using TEMPO as the organo-electrocatalyst.
We have achieved the catalytic dehydrogenation of N-heterocycles in
an anode and the release of H2 in a cathode using an undivided-cell
system. A variety of six-membered and five-membered nitrogen-heteroarenes
can be synthesized in good yields in this system. In addition, this
protocol can also be used in the application of important molecular
synthesis. Our electrochemical strategy provides a mild and metal-free
route for (hetero)aromatic compounds synthesis via the CAD strategy.
In this work, we have described an alternative alkenylation approach to illustrate the metal-like behaviour of iodine in cross-coupling reactions. Alkenylation could proceed through iodide catalysed radical initiation, radical addition and iodine promoted alkenyl functionality recovery. Catalytic HI elimination similar to the β-hydride elimination of transition metals was realized for the radical alkenylation of sulfonyl hydrazides. Operando IR and cyclic voltammetry experiments were carried out to confirm the crucial role of iodine in the radical alkenylation process.
Conductive polymers (CPs) integrate the inherent characteristics of conventional polymers and the unique electrical properties of metals. They have aroused tremendous interest over the last decade owing to their high conductivity, robust and flexible properties, facile fabrication, and cost‐effectiveness. Compared to bulk CPs, porous CPs with well‐defined nano‐ or microstructures possess open porous architectures, high specific surface areas, more exposed reactive sites, and remarkably enhanced activities. These attractive features have led to their applications in sensors, energy storage and conversion devices, biomedical devices, and so on. In this review article, the different strategies for synthesizing porous CPs, including template‐free and template‐based methods, are summarized, and the importance of tuning the morphology and pore structure of porous CPs to optimize their functional performance is highlighted. Moreover, their representative applications (energy storage devices, sensors, biomedical devices, etc.) are also discussed. The review is concluded by discussing the current challenges and future development trend in this field.
Oxidative
carbonylation using carbon monoxide has evolved as an
attractive tool to valuable carbonyl-containing compounds, while mixing
CO with a stoichiometric amount of a chemical oxidant especially oxygen
is hazardous and limits its application in scale-up synthesis. By
employing anodic oxidation, we developed an electrochemical palladium-catalyzed
oxidative carbonylation of arylhydrazines with alkynes, which is regarded
as an alternative supplement of the carbonylative Sonogashira reaction.
Combining an undivided cell with constant current mode, oxygen-free
conditions avoids the explosion hazard of CO. A diversity of ynones
are efficiently obtained using accessible arylhydrazines and alkynes
under copper-free conditions. A possible mechanism of the electrochemical
Pd(0)/Pd(II) cycle is rationalized based upon cyclic voltammetry,
kinetic studies, and intermediates experiments.
A facile method of producing stable aqueous dispersion of graphene/polyaniline (PANI) composite is described, which involves the in situ polymerization of aniline on the surface of graphene with the aid of polystyrene sulfonic acid (PSS). The prepared aqueous graphene/PANI composite dispersion was very stable and no aggregation or precipitation was observed for several weeks. The excellent aqueous dispersibility and stability of the graphene/PANI composite is attributed to the cooperative interactions of p stacking interaction between PSS, PANI, and the graphene basal planes, and the electrostatic repulsions between negatively charged PSS bound on graphene/PANI composite. Fourier transform-infra-red spectrometry (FTIR), ultraviolet-visible spectra (UV-vis), and Raman spectra confirmed the interaction of PANI and graphene in the composite, which effectively delocalize the electrons. In addition, the composite showed three orders of magnitude of conductivity increase compared with pure PANI. This new approach is simple, fast, and straightforward, representing a significant improvement in the processing of graphene/PANI composites. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: [4888][4889][4890][4891][4892][4893][4894] 2012
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