Latest ArticlesTwo-dimensional (2D) transition metal dichalcogenide (TMD) nanosheets have attracted considerable attention owing to their diverse properties and great potential in a wide range of applications. In order to further tune their properties and then broaden their application domain, large efforts have been devoted into engineering the structures of 2D TMD nanosheets at atomic scale, especially the alloying technology. Alloying different 2D TMD nanosheets into 2D alloys not only offers the opportunities to fine-tune their physical/chemical properties, but also opens up some unique properties, which are highly desirable for wide applications including electronics, optoelectronics and catalysis. This review summarizes the recent progress in the preparation, characterization and applications of 2D alloyed TMD nanosheets.
Since the discovery of graphene, two-dimensional (2D) semiconductors have been attracted intensive interest due to their unique properties. They have exhibited potential applications in next generation electronic and optoelectronic devices. However, most of the 2D semiconductor are known to suffer from the ambient oxidation which degrade the materials and therefore hinder us from the intrinsic materials' properties and the optimized performance of devices. In this review, we summarize the recent progress on both fundamentals and applications of the oxidations of 2D semiconductors. We begin with the oxidation mechanisms in black phosphorus, transition metal dichalcogenides and transition metal monochalcogenides considering the factors such as oxygen, water, and light. Then we show the commonly employed passivation techniques. In the end, the emerging applications utilizing controlled oxidations will be introduced.
Porous carbon materials have attracted much attention in the field of organic synthesis in recent years, due to their tunable properties, excellent catalytic activity and stability. Biomass-based carbohydrates emerge as an ideal precursor for the generation of these materials owing to their renewability, low cost, non-toxicity and high content of functional groups. Thus, carbon materials prepared from carbohydrates is of considerable importance for the sustainable development of organic chemistry. The present review not only summarizes recent examples of carbohydrate-derived porous carbon material-catalyzed organic reactions including the oxidation, hydrogenation, cross-coupling, esterification and condensation reactions, but also introduces the preparation and functionalization strategies of these materials. Furthermore, the challenges and opportunities of organic synthesis over these sustainable materials have also been addressed. This review will stimulate further research on exploring novel carbohydrate-derived porous carbon materials and new sustainable organic synthetic processes over these materials.
A palladium-catalyzed 2-alkylation of indoles with α-bromo esters is developed by employing a P, P=O ligand. The method features excellent regioselectivities, mild reaction conditions, and good functional group compatibility. The employment of the P, P=O ligand as well as 4 Å molecular sieves were crucial for the success of the transformation. Mechanistic studies indicate the reaction proceed through a radical pathway.
A facile access to mono-C-alkynyl-o-carboranes from o-carboranes and arylsulfonylacetylenes was developed. This facile process tolerates a wide variety of functional groups, occurs at mild conditions in one-pot procedure with short reaction time. The obtained mono-C-alkynyl-o-carboranes can be easily derivatized to synthesize 1, 2-difunctionalized o-carboranes. This work provides a useful tool for the functionalization of o-carboranes.
Selenization reaction with the in situ prepared NaHSe has been successfully developed to occur in aqueous solution. The technique affords a method to upload the bioactive Se element on cotton products in semi-industrial scale. The antibacterial tests revealed that the selenized cotton possessed a potent and prolonged antimicrobial effect against both Gram-positive S. aureus and Gram-negative E. coli bacteria. This work discloses a practical method for preparing the selenium-containing antibacterial materials concisely and directly with industrial application potential.
Glutathione thiol-reactive pillar[6]arene (TWP6) is designed and synthesized as the first example of reducing agent-reactive host molecule. TWP6 shows high affinity binding towards suitable anti-tumor drugs and guests. Doxorubicin-based acid-labile prodrugs and TWP6 are used to construct supramolecular vesicles, which are also loaded with camptothecin. The supramolecular vesicles loaded with two drugs demonstrate glutathione- and acid-responsive drug release as well as sequential release to both stimuli types. Supramolecular vesicles show combination therapeutic effect towards tumor cells in vitro.
Microarray technology has been widely applied in biomedical research. The key to microarray study is to develop efficient immobilization method. In this study, we designed a new reversible microarray immobilization method based on thiol-quinone reaction. A quinone-functionalized slide was fabricated through H2O2 treatment of dopamine-coated slides. Various thiol-containing molecules can be anchored onto the quinone-functionalized slides via thioether linker, which could be cleaved under H2O2 treatment to regenerate quinone groups on the surface. The highly versatile approach can be widely used for immobilization of various thiol-containing molecules.
Thiolate-bridged hetero-bimetallic complexes [Cp*M(MeCN)N2S2FeCl][PF6] (2, M = Ru; 3, M = Co, Cp* = η5-C5Me5, N2S2 = N, N'-dimethyl-3, 6-diazanonane-1, 8-dithiolate) were prepared by self-assembly of dimer [N2S2Fe]2 with mononuclear precursor [Cp*Ru(MeCN)3][PF6] or [Cp*Co(MeCN)3][PF6]2 in the presence of CHCl3 as a chloride donor. Complexes 2 and 3 exhibit obviously different redox behaviors investigated by cyclic voltammetry and spin density distributions supported by DFT calculations. Notably, iron-cobalt complex 3 possesses versatile reactivities that cannot be achieved for complex 2. In the presence of CoCp2, complex 3 can undergo one-electron reduction to generate a stable formally CoIIFeII complex [Cp*CoN2S2FeCl] (4). Besides, the terminal chloride on the iron center in 3 can be removed by dehalogenation agent AgPF6 or exchanged with azide to afford the corresponding complexes [Cp*Co(MeCN)N2S2Fe(MeCN)][PF6]2 (5) and [Cp*Co(MeCN)N2S2Fe(N3)][PF6] (6). In addition, complexes 2, 3 and 4 show distinct catalytic reactivity toward the disproportionation of hydrazine into ammonia. These results may be helpful to understand the vital role of the heterometal in some catalytic transformations promoted by heteromultinuclear complexes.
A new electrochemical strategy for trifluoromethylation/cyclization using TfNHNHBoc as a CF3 source was established. This approach was realized by the direct electrolysis of TfNHNHBoc under external oxidant-free and catalyst-free conditions, and afforded various trifluoromethylated oxindoles with good functional group compatibility and broad substrate scope. Preliminary mechanistic studies show that the reaction proceeds by a radical process.