We report an electrophotocatalytic process that enables the thiocyanation and sulfonylation/cyclization of alkenes. It is applicable to a wide range of unactivated alkenes, using the inexpensive photocatalyst 2,4,6-triphenylpyrylium tetrafluoroborate (TPPT) to produce a diverse array of heterocycles containing sulfonyl and thiocyano groups with good functional group tolerance. The protocol operates under mild, chemical oxidant- and transition-metal-free, with a broad scope of substrates.
View Article and Find Full Text PDFTwo general protocols for the regioselective electrochemically enabled sulfonylation cyclization of -alkenylacrylamides with sodium sulfinates or sulfonyl hydrazides were described. These methods were carried out under mild, chemical oxidant-free, and transition-metal-free conditions with a broad substrate scope and good functional group tolerance to provide sulfonyl-containing 4-pyrrolin-2-ones, which is readily scalable to the gram scale.
View Article and Find Full Text PDFThree hybrid electrochemical protocols, which involve the energy transfer, direct photolysis and N-hydroxyphthalimide catalyst, respectively, are presented for the selenylation/cyclization of the fragile substrates of 3-aza-1,5-dienes with diorganyl diselenides to afford 3-selenomethyl-4-pyrrolin-2-ones. The two electrophotocatalytic reactions and the indirect electrolysis one are both regioselective and external-oxidant- and transition-metal-free, and are associated with a broad substrate scope and high Se-economy, and all three methods are amenable to gram-scale syntheses, late-stage functionalizations, sunlight-induced experiments and all-solar-driven syntheses.
View Article and Find Full Text PDFEnantioenriched α-tertiary-α-aminoacid and α-chiral-β-aminoacid derivatives play an important role in biological science and pharmaceutical chemistry. Thus, the development of methods for their synthesis is highly valuable and yet remains challenging. Herein, an unprecedented catalyst-controlled regiodivergent and enantioselective formal hydroamination of N,N-disubstituted acrylamides with aminating agents has been developed, accessing enantioenriched α-tertiary-α-aminolactam and α-chiral-β-aminoamide derivatives.
View Article and Find Full Text PDFThe present study identifies investment in Africa's cultural and creative industries (CCIs) as one of the strategic moves in the right direction for achieving sustainable development across the African continent. Cultural and creative industries (CCIs) offer an alternative approach to development through their wealth creation potential, socioeconomic development, employment opportunities, and promotion of cultural diversity. Nevertheless, CCIs are yet to feature categorically as a development strategy, owing to their many challenges, as indicated by the study.
View Article and Find Full Text PDFThe rational design of previously unidentified materials that could realize excellent electrochemical-controlled optical and charge storage properties simultaneously, are especially desirable and useful for fabricating smart multifunctional devices. Here, a facile synthesis of a 1D -d conjugated coordination polymer (Ni-BTA) is reported, consisting of metal (Ni)-containing nodes and organic linkers (1,2,4,5-benzenetetramine), which could be easily grown on various substrates via a scalable chemical bath deposition method. The resulting Ni-BTA film exhibits superior performances for both electrochromic and energy storage functions, such as large optical modulation (61.
View Article and Find Full Text PDFThe development of enantioselective alkyl-alkyl cross-couplings with coinstantaneous formation of a stereogenic center without the use of sensitive organometallic species is attractive yet challenging. Herein, we report the intermolecular regio- and enantioselective formal hydrofunctionalizations of acrylamides, forging a stereogenic center α-position to the newly formed C -C bond for the first time. The use of a newly developed chiral ligand enables the electronically-reversed formal hydrofunctionalizations, including hydroalkylation, hydrobenzylation, and hydropropargylation, offering an efficient way to access diverse enantioenriched amides with a tertiary α-stereogenic carbon center which is facile to racemize.
View Article and Find Full Text PDFThe design and construction of 3D architectures enabled by stimuli-responsive soft materials can yield novel functionalities for next generation soft-bodied actuating devices. Apart from additive manufacturing processes, origami inspired technology offers an alternative approach to fabricate 3D actuators from planar materials. Here we report a class of near-infrared (NIR) responsive 3D active origamis that deploy, actuate and transform between multistable structural equilibria.
View Article and Find Full Text PDFA formal [4 + 2] cyclization of easily available ketene dithioacetals with acyl chlorides has been developed. Mediated by lithium bis(trimethylsilyl)amide, a series of γ-pyrones were obtained with a broad substrate scope. This unprecedented formal [4 + 2] cyclization provides a novel mode for ketene dithioacetals as versatile synthons.
View Article and Find Full Text PDFA series of tunable iminium ions, generated in situ by the condensation of 4-trifluoromethyl-p-quinols with cyclic amines, can lead to the divergent synthesis of trifluoromethylated arylamines in a single step via redox-neutral isomerization. The direct α- and β-functionalization of saturated amines can be achieved regioselectively under mild conditions.
View Article and Find Full Text PDFIn recent years, numerous methods have emerged for the synthesis of trifluoromethylated arenes based on the late-stage introduction of a trifluoromethyl group onto an aryl ring. In sharp comparison, the synthesis of trifluoromethylated arenes based on the pre-introduction of a trifluoromethyl group onto an "aromatic to be" carbon has rarely been addressed. It has been found that 4-trifluoromethyl-p-quinol silyl ethers, the readily available and relatively stable compounds, can act as dielectrophiles to be applied to multi-component reactions for the synthesis of various trifluoromethylated arenes.
View Article and Find Full Text PDFSome oxides have the ability to trap excess electrons in the form of small polarons. Here, using first-principles techniques, we investigate the interaction of excess electrons with α-MoO3. Polarons are found to be about 0.
View Article and Find Full Text PDFNanocrystalline molybdenum oxide (α-MoO3) thin films with iso-oriented crystalline layers were synthesised by the anodisation of Mo foils. Upon band-gap excitation using light illumination, α-MoO3 generates excited electrons for reductive reactions and stores some of the excited electrons in its layered crystalline structure via alkali cation intercalation. These stored electrons can be subsequently discharged from α-MoO3 to allow reductive reactions to continue to occur under non-illuminated conditions.
View Article and Find Full Text PDFNanostructured molybdenum oxide (α-MoO3 ) thin film photoelectrodes were synthesised by anodisation. Upon band gap-excitation by light illumination, α-MoO3 is able to store a portion of the excited charges in its layered structure with the simultaneous intercalation of alkali cations. The stored electrons can be discharged from α-MoO3 for utilisation under dark conditions, and α-MoO3 is able to recharge itself with successive illuminations to behave as a 'self-photo-rechargeable' alkali-ion battery.
View Article and Find Full Text PDFJ Colloid Interface Sci
February 2011
The effect of gold attachment on the physical characteristics, cellular uptake, gene expression efficiency, and biocompatibility of magnetic iron oxide (MNP) vector was investigated in vitro in BHK21 cells. The surface modification of magnetite with gold was shown to alter the morphology and surface charge of the vector. Nonetheless, despite the differences in the surface charge with and without gold attachment, the surface charge of all vectors were positive when conjugated with PEI/DNA complex, and switched from positive to negative when suspended in cell media containing serum, indicating the adsorption of serum components onto the composite.
View Article and Find Full Text PDFBased on a low-temperature route, monodispersed CoFe(2)O(4) microspheres (MSs) were fabricated through aggregation of primary nanoparticles. The microstructural and magnetic characteristics of the as-prepared MSs were characterized by X-ray diffraction/photoelectron spectroscopy, scanning/transmitting electron microscopy, and vibrating sample magnetometer. The results indicate that the diameters of CoFe(2)O(4) MSs with narrow size distribution can be tuned from over 200 to ~330 nm.
View Article and Find Full Text PDFShi Yan Sheng Wu Xue Bao
February 2003
The shutter expression vector pPREUT was constructed from the plasmid pPRS-1 containing the endogenous small plasmid of Plectonema boryanum. The expression elements such as heat shock gene groESL promoter, foreign gene Ub-thymosin alpha 1, rbcS polyA terminator and Kanamycin resistance gene were all included. The shutter plasmid pPREUT was directly transferred into Synechococcus sp.
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