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Organic-molecule insertion into MoS2 is becoming a research hotspot owing to the expanded interlayer spacing and improved electrochemical energy storage. Up to now, the effect of organic molecules with different configurations on capacitive energy storage has not been clarified. Herein, we have innovatively selected two types of organic molecules to insert into MoS2, whose configurations are linear long-chain (cetyltrimethylammonium bromide, CTAB) and tetrahedral symmetrical branched-chain (tetrabutylammonium bromide, TBAB). The interlayer spacing extends from 6.3 Å to 9.8 Å and 10.3 Å after TBAB and CTAB intercalation, respectively. Additionally, the insertion of organic molecules not only increases the content of high-valent Mo (Mo5+, Mo6+), but also introduces pyrrolic N, pyridinic N and N+, which are beneficial for capacitive energy storage. Interestingly, the linear long-chain CTAB causes MoS2 to present a broken shell hollow sphere, which can provide more channels and space for ion storage. More importantly, the migration barrier energy of Na ions between MoS2 layers and CTAB molecules is 1.01 eV, which is significantly lower than that of Na ions between MoS2 and TBAB (1.85 eV), indicating that linear organic molecules are more appropriate for ion-diffusion kinetics. This work provides a prototype for studying the effect of the organic molecular configuration on the capacitive energy storage of intercalated MoS2. [ABSTRACT FROM AUTHOR]

A novel and efficient catalyst-free and oxidant-free tandem aza-Mannich/cyclization/aromatization reaction of C,N-cyclic azomethine imines with enamides has been developed. This practical one-step protocol enables a simple and environmentally friendly route toward the straightforward synthesis of highly substituted 5,6-dihydropyrazolo[5,1-a]isoquinolines. Different types of enamides and enamines, especially enamides derived from marketed drugs as well as bioactive molecules, are suitable substrates. CB1 cannabinoid receptor antagonist could be synthesized efficiently based on this methodology, illustrating that this would be a practical strategy to synthesize valuable structural motifs. [ABSTRACT FROM AUTHOR]

Metallic 1T-phase MoS2 (1T-MoS2) nanosheets with large interlayer spacing are considered to be a high-energy electrode material for use in supercapacitors; however, the electrochemical storage mechanism of 1T-MoS2 involves ion intercalation, resulting in energy storage being limited at high current densities and showing poor rate capability. Here, a 1T-MoS2/Ti3C2Tx heterostructure was assembled from metallic 1T-MoS2 nanosheets coupled with a Ti3C2 MXene through one-pot hydrothermal synthesis, and the electrochemical storage mechanisms were investigated. The electrochemical advantages of 1T-MoS2 and Ti3C2Tx can be united via synergistic interplay in the heterostructure. The high specific capacitance is attributed to the metallic properties and the large interlayer spacing of the 1T-MoS2 component. More importantly, ultra-high rate capability is realized due to fast electron and ion transport originating from Ti3C2Tx. In addition, an all-solid-state flexible asymmetric aqueous supercapacitor (FASC) constructed with 1T-MoS2/Ti3C2Tx as the negative electrode and δ-MnO2 as the positive electrode shows a wide potential window of 1.8 V and a high areal energy density of 68.8 μW h cm−2 at 4500 μW cm−2. This work will provide a reference for studying electrochemical storage mechanisms in heterostructures, and it demonstrates the promise of the 1T-MoS2/MXene heterostructure for supercapacitor use. [ABSTRACT FROM AUTHOR]