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971.
Dr. Jiang Peng Jiakun Bai Xiumian Cao Jieting He Prof. Weiqing Xu Dr. Junhui Jia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(64):16036-16042
Elastic organic single crystals with light-emitting and multi-faceted bending properties are extremely rare. They have potential application in optical materials and have attracted the extensive attention of researchers. In this paper, we reported a structurally simple barbituric derivative DBDT , which was easily crystallized and gained long needle-like crystals (centimeter-scale) in DCM/CH3OH (v/v=2/8). Upon applying or removing the mechanical force, both the (100) and (040) faces of the needle-like crystal showed reversible bending behaviour, showing the nature of multi-faceted bending. The average hardness (H) and elastic modulus (E) were 0.28±0.01 GPa and 4.56±0.03 GPa for the (040) plane, respectively. Through the analysis of the single crystal data, it could be seen that the van der waals (C−H⋅⋅⋅π and C−H⋅⋅⋅C), H-bond (C−H⋅⋅⋅O) and π⋅⋅⋅π interactions between molecules were responsible for the generation of the crystal elasticity. Interestingly, elastic crystals exhibited optical waveguide characteristics in straight or bent state. The optical loss coefficients measured at 627 nm were 0.7 dBmm−1 (straight state) and 0.9 dBmm−1 (bent state), while the optical loss coefficient (α) were 1.5 dBmm−1 (straight state) and 1.8 dBmm−1 (bent state) at 567 nm. Notably, the elastic organic molecular crystal based on barbituric derivative could be used as the candidate for flexible optical devices. 相似文献
972.
Organic halides absorbed without solvent onto sodium phenylsulfinate on alumina (1) gave phenylsulfones (2) under microwave or ultrasound activation. 相似文献
973.
To date, investigations onto the regulation of reactants mass transfer has been paid much less attention in environmental catalysis. Herein, we demonstrated that by rationally designing the adsorption sites of multi-reactants, the pollutant destruction efficiency, product selectivity, reaction stability and secondary pollution have been all affected in the catalytic chlorobenzene oxidation (CBCO). Experimental results revealed that the co-adsorption of chlorobenzene (CB) and gaseous O2 at the oxygen vacancies of CeO2 led to remarkably high CO2 generation, owning to their short mass transfer distance on the catalyst surface, while their separated adsorptions at Brönsted HZSM-5 and CeO2 vacancies resulted in a much lower CO2 generation, and produced significant polychlorinated byproducts in the off-gas. However, this separated adsorption model yielded superior long-term stability for the CeO2/HZSM-5 catalyst, owning to the protection of CeO2 oxygen vacancies from Cl poisoning by the preferential adsorption of CB on the Brönsted acidic sites. This work unveils that design of environmental catalysts needs to consider both of the catalyst intrinsic property and reactant mass transfer; investigations of the latter could pave a new way for the development of highly efficient catalysts towards environmental pollution control. 相似文献
974.
Weiguo Zhang Junyu Xu Jing Cao Chao Fang Jindong Zhu Tao Lu Ding Du 《Tetrahedron》2017,73(23):3249-3254
An in situ activation of isatin-derived α,β-unsaturated acids 2 for the generation of isatin-derived α,β-unsaturated acyl azoliums II was described. The acyl azoliums II were successfully applied to undergo a formal [3 + 3] annulation with 1,3-dicarbonyl compounds to access functionalized 3,4′-spirooxindole δ-lactones 4. A scale-up synthesis and an enantioselective variant of this protocol were also investigated. The stable and easily prepared acids 2 may be further utilized as promising versatile electrophilic 1,3-synthons for divergent synthesis of spirooxindoles. 相似文献
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Zhang Wenfan Liu Yan Cao Shengli Chen Jiahui Zhang Zexia Zhang Jiazhong 《Nonlinear dynamics》2017,90(3):1841-1850
Nonlinear Dynamics - The flow-induced vibration of two-dimensional wing coupled with two nonlinear energy sinks (NESs) under freestream is studied by numerical methods, and the relationship between... 相似文献
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