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2020 Volume 83 Issue 7
2020, 83(7): 578-587
Abstract:
The interplay between polymer science and supramolecular chemistry leads to formation of various supramolecular polymers. Supramolecular polymers refer to polymeric arrays whose monomers are connected together through directional noncovalent interactions, resulting in polymeric properties in solution and bulk. So far, most of supramolecular polymers are prepared in homogeneous solutions. However, it remains difficult to controllably prepare supramolecular polymers due to the spontaneous self-assembly process of supramolecular polymerization in solutions. To solve this problem, we can transfer supramolecular polymerization from solutions onto interfaces owing to the unique advantages of interfacial polymerization. For example, supramolecular polymers with higher molecular weights can be obtained through supramolecular interfacial polymerization than that of prepared through solution polymerization. Moreover, two-dimensional supramolecular polymeric membranes fabricated by interfacial polymerization are inherently defect-free, large-area and ordered. In this review, we will highlight recent and important progresses in the area of supramolecular polymers at interfaces, including liquid-liquid, gas-liquid and solid-liquid interfaces. Subsequently, the applications of functional supramolecular polymers prepared by interfacial polymerization are also introduced, such as gas separation, cargo loading and catalysis. Finally, some of the current challenges and opportunities of supramolecular polymers at interfaces are proposed and discussed.
The interplay between polymer science and supramolecular chemistry leads to formation of various supramolecular polymers. Supramolecular polymers refer to polymeric arrays whose monomers are connected together through directional noncovalent interactions, resulting in polymeric properties in solution and bulk. So far, most of supramolecular polymers are prepared in homogeneous solutions. However, it remains difficult to controllably prepare supramolecular polymers due to the spontaneous self-assembly process of supramolecular polymerization in solutions. To solve this problem, we can transfer supramolecular polymerization from solutions onto interfaces owing to the unique advantages of interfacial polymerization. For example, supramolecular polymers with higher molecular weights can be obtained through supramolecular interfacial polymerization than that of prepared through solution polymerization. Moreover, two-dimensional supramolecular polymeric membranes fabricated by interfacial polymerization are inherently defect-free, large-area and ordered. In this review, we will highlight recent and important progresses in the area of supramolecular polymers at interfaces, including liquid-liquid, gas-liquid and solid-liquid interfaces. Subsequently, the applications of functional supramolecular polymers prepared by interfacial polymerization are also introduced, such as gas separation, cargo loading and catalysis. Finally, some of the current challenges and opportunities of supramolecular polymers at interfaces are proposed and discussed.
2020, 83(7): 588-599
Abstract:
Carbon nanotubes (CNTs) have drawn intensive research interest in the past near 30 years due to their excellent properties and wide applications. In a large number of different types of CNTs, ultralong CNTs usually have perfect structures and lengths up to centimeters, even decimeters, showing extraordinary mechanical, electrical, and thermal properties. Ultralong CNTs are promising candidates for transparent displays, nanoelectronics, superstrong tethers, aeronautics and aerospace, etc. The controlled synthesis of ultralong CNTs with perfect structures is the key to fully exploit the extraordinary properties of CNTs. Over the past two decades, significant progress has been made in the study of ultralong CNTs, but there are also great challenges in controlled synthesis and mass production of ultralong CNTs, which limits their application. In this review, the progress on the growth mechanism, structure control, selective synthesis and extraordinary properties of ultralong CNTs and the innovative ideas in them is summarized. Meanwhile, the current challenges and future priorities were discussed. We hope that this review will shed light on the controlled synthesis, mass production and future application of ultralong CNTs and play a role in promoting the mass production and industrialization of ultralong CNTs with perfect structures.
Carbon nanotubes (CNTs) have drawn intensive research interest in the past near 30 years due to their excellent properties and wide applications. In a large number of different types of CNTs, ultralong CNTs usually have perfect structures and lengths up to centimeters, even decimeters, showing extraordinary mechanical, electrical, and thermal properties. Ultralong CNTs are promising candidates for transparent displays, nanoelectronics, superstrong tethers, aeronautics and aerospace, etc. The controlled synthesis of ultralong CNTs with perfect structures is the key to fully exploit the extraordinary properties of CNTs. Over the past two decades, significant progress has been made in the study of ultralong CNTs, but there are also great challenges in controlled synthesis and mass production of ultralong CNTs, which limits their application. In this review, the progress on the growth mechanism, structure control, selective synthesis and extraordinary properties of ultralong CNTs and the innovative ideas in them is summarized. Meanwhile, the current challenges and future priorities were discussed. We hope that this review will shed light on the controlled synthesis, mass production and future application of ultralong CNTs and play a role in promoting the mass production and industrialization of ultralong CNTs with perfect structures.
2020, 83(7): 600-609, 587
Abstract:
Azobenzene compounds are very attractive and commonly used photoresponsive materials. This minireview mainly introduced the photoresponsive property of azobenzene. The syntheses and the mechanisms of photoinduced reversible solid-to-liquid transitions of some azobenzene-containing polymers (azopolymers) were further introduced. The potential applications of azopolymers based on photoinduced reversible solid-to-liquid transitions were also presented, such as adhesive materials, photoactuators, photothermally conductive switching devices and non-thermal nanoimprinting.
Azobenzene compounds are very attractive and commonly used photoresponsive materials. This minireview mainly introduced the photoresponsive property of azobenzene. The syntheses and the mechanisms of photoinduced reversible solid-to-liquid transitions of some azobenzene-containing polymers (azopolymers) were further introduced. The potential applications of azopolymers based on photoinduced reversible solid-to-liquid transitions were also presented, such as adhesive materials, photoactuators, photothermally conductive switching devices and non-thermal nanoimprinting.
2020, 83(7): 610-614
Abstract:
Organosilane and organostannane compounds have been well-known as nucleophilic fragments in transition metal catalyzed cross-coupling reactions. However, organogermanium is less familiar to us in such case. Cross-coupling of germanium nucleophiles initially only verified germanium itself as a possible 'cross-coupling element', gradually showed its unique behavior, which attracted more concentration on these reagents. This article is comprised of the introducing methods and properties in cross-coupling reactions of these germanium fragments by means of their structure classification.
Organosilane and organostannane compounds have been well-known as nucleophilic fragments in transition metal catalyzed cross-coupling reactions. However, organogermanium is less familiar to us in such case. Cross-coupling of germanium nucleophiles initially only verified germanium itself as a possible 'cross-coupling element', gradually showed its unique behavior, which attracted more concentration on these reagents. This article is comprised of the introducing methods and properties in cross-coupling reactions of these germanium fragments by means of their structure classification.
2020, 83(7): 615-620
Abstract:
Quinoline is an important class of heterocyclic compounds, and research on the synthesis of quinoline compounds has attracted much attention. It is simple and efficient to prepare substituted quinolines though direct C-H bond functionalization of quinolines. However, the C5-selective C-H bond functionalization of quinolines is still a challenge. Most current methods are achieved by transition metal catalysis. The reactions under transition metal-free conditions are desired. In this paper, the recent advance of C5 C-H bond functionalization of quinolines under transition-metal free conditions is reviewed according to the types of bond (C-X, C-N, C-S, C-O and C-C) formation. And the research status and current problems in this field are also summarized.
Quinoline is an important class of heterocyclic compounds, and research on the synthesis of quinoline compounds has attracted much attention. It is simple and efficient to prepare substituted quinolines though direct C-H bond functionalization of quinolines. However, the C5-selective C-H bond functionalization of quinolines is still a challenge. Most current methods are achieved by transition metal catalysis. The reactions under transition metal-free conditions are desired. In this paper, the recent advance of C5 C-H bond functionalization of quinolines under transition-metal free conditions is reviewed according to the types of bond (C-X, C-N, C-S, C-O and C-C) formation. And the research status and current problems in this field are also summarized.
2020, 83(7): 621-640
Abstract:
Recently, the metal halide perovskites with ABX3 structure (A=MA+, FA+ or Cs+; B=Pb2+, Sn2+; X=Br- or I- halide cations) have a series of exciting and excellent optoelectronic performances, which is recognized as one of the research frontiers and hot spots in the field of solar cells. However, the problems in terms of the toxic lead component and the instability under ambient conditions greatly hamper the progress for large-scale commercialization of perovskite solar cells. Thereby, it is urgent to develop novel and efficient solar cells based on lead-free metal halide perovskites. In the present work, the state-of-the-art research activities and recent progresses in the exploration of solar cells based on environmental-friendly lead-free metal halide perovskites have been overviewed. The fabrication, optoelectronic performance as well as the stability of the as-constructed solar cells based on lead-free metal halide perovskites have been discussed. The prospects in this area have been proposed.
Recently, the metal halide perovskites with ABX3 structure (A=MA+, FA+ or Cs+; B=Pb2+, Sn2+; X=Br- or I- halide cations) have a series of exciting and excellent optoelectronic performances, which is recognized as one of the research frontiers and hot spots in the field of solar cells. However, the problems in terms of the toxic lead component and the instability under ambient conditions greatly hamper the progress for large-scale commercialization of perovskite solar cells. Thereby, it is urgent to develop novel and efficient solar cells based on lead-free metal halide perovskites. In the present work, the state-of-the-art research activities and recent progresses in the exploration of solar cells based on environmental-friendly lead-free metal halide perovskites have been overviewed. The fabrication, optoelectronic performance as well as the stability of the as-constructed solar cells based on lead-free metal halide perovskites have been discussed. The prospects in this area have been proposed.
2020, 83(7): 641-651
Abstract:
Cyclic compounds with carbonyl groups comprise of cyclic ketones, lactones, and lactams. The α-C(sp3)-H arylation of these cyclic compounds is an important type of C-H functionalization, exhibiting high efficiency in formation of C(sp3)-C(sp2) bonds, playing an important role in organic synthesis, and attracting majority of interests from organic and medicinal communities. Up to now, various α-C(sp3)-H arylations of these cyclic compounds have been reported. This article mainly reviews the research progress of such reactions in the past two decades.
Cyclic compounds with carbonyl groups comprise of cyclic ketones, lactones, and lactams. The α-C(sp3)-H arylation of these cyclic compounds is an important type of C-H functionalization, exhibiting high efficiency in formation of C(sp3)-C(sp2) bonds, playing an important role in organic synthesis, and attracting majority of interests from organic and medicinal communities. Up to now, various α-C(sp3)-H arylations of these cyclic compounds have been reported. This article mainly reviews the research progress of such reactions in the past two decades.
2020, 83(7): 652-658
Abstract:
It has been reported that precisely regulating the electronic structures of the active site is one of the most effective means to realize precise catalysis, which often includes lattice strain and charge transfer, etc. In doping systems, some new theories, such as the Atom-Realm (AR) effect, have been used to explain the changes in physical and chemical properties of the substrates caused by the geometry and electronic structures of the active heteroatom sites. Based on the low-entropy alloy and using the first-principles calculations, we report a new strategy for achieving precise catalysis through regulating the orbitals and spin of the active sites, i.e. doping Fe atoms in Pt to change its d-orbitals for the regulation of catalytic performance. We established both the models of pure Pt and Pt-Fe alloy and calculated the O2 adsorption energy on different active sites. We found that doping Fe atoms in pure Pt can weaken the binding of O2-Pt without affecting the O2 dissociation. Based on the projected density of states (PDOS) analysis, the hybridization of Fe-3d and Pt-5d states leads to the shift of atomic orbitals as well as the spin polarization of Pt metal. Therefore, part of the electronic states of Pt move above the Fermi level and overlap with O2-π*, making the hybridization of O2-π* and Pt-5d states in Pt-Fe alloy much stronger than that in pure Pt. The regulation of d-orbitals results in the improvement of the catalytic activity of O2 on the surface of Pt-Fe alloy. Our study predicts that the orbital catalysis and spin catalysis will provide an effective method for precise catalysis as well as high-efficient catalysts design.
It has been reported that precisely regulating the electronic structures of the active site is one of the most effective means to realize precise catalysis, which often includes lattice strain and charge transfer, etc. In doping systems, some new theories, such as the Atom-Realm (AR) effect, have been used to explain the changes in physical and chemical properties of the substrates caused by the geometry and electronic structures of the active heteroatom sites. Based on the low-entropy alloy and using the first-principles calculations, we report a new strategy for achieving precise catalysis through regulating the orbitals and spin of the active sites, i.e. doping Fe atoms in Pt to change its d-orbitals for the regulation of catalytic performance. We established both the models of pure Pt and Pt-Fe alloy and calculated the O2 adsorption energy on different active sites. We found that doping Fe atoms in pure Pt can weaken the binding of O2-Pt without affecting the O2 dissociation. Based on the projected density of states (PDOS) analysis, the hybridization of Fe-3d and Pt-5d states leads to the shift of atomic orbitals as well as the spin polarization of Pt metal. Therefore, part of the electronic states of Pt move above the Fermi level and overlap with O2-π*, making the hybridization of O2-π* and Pt-5d states in Pt-Fe alloy much stronger than that in pure Pt. The regulation of d-orbitals results in the improvement of the catalytic activity of O2 on the surface of Pt-Fe alloy. Our study predicts that the orbital catalysis and spin catalysis will provide an effective method for precise catalysis as well as high-efficient catalysts design.
2020, 83(7): 659-664
Abstract:
In this study, graphene quantum dots (GQDs) with catalase activity were synthesized from citric acid. GQDs modified by tyramine (TYR-GQDs) can reduce hydrogen peroxide to hydroxyl radicals. GQDs aggregates through the cross-linking between phenolic hydroxyls, which leads to fluorescence quenching. Since cholesterol oxidase can catalyze the oxidation of cholesterol to produce H2O2, a fluorescence sensor for detecting cholesterol was established based on TYR-GQDs. The experimental results showed that under the condition of pH=7.4, the fluorescence quenching rate of TYR-GQDs exlibits a good linear relationship with the logarithm of cholesterol concentration (2.67×10-8~2.67×10-3 mol/L), and the detection limit is 9.32×10-9 mol/L. The interference experiment showed that the fluorescent sensor has high selectivity for cholesterol and can be used for the detection of free cholesterol in human serum. The recovery of standard addition is 96.55%~100.14%.
In this study, graphene quantum dots (GQDs) with catalase activity were synthesized from citric acid. GQDs modified by tyramine (TYR-GQDs) can reduce hydrogen peroxide to hydroxyl radicals. GQDs aggregates through the cross-linking between phenolic hydroxyls, which leads to fluorescence quenching. Since cholesterol oxidase can catalyze the oxidation of cholesterol to produce H2O2, a fluorescence sensor for detecting cholesterol was established based on TYR-GQDs. The experimental results showed that under the condition of pH=7.4, the fluorescence quenching rate of TYR-GQDs exlibits a good linear relationship with the logarithm of cholesterol concentration (2.67×10-8~2.67×10-3 mol/L), and the detection limit is 9.32×10-9 mol/L. The interference experiment showed that the fluorescent sensor has high selectivity for cholesterol and can be used for the detection of free cholesterol in human serum. The recovery of standard addition is 96.55%~100.14%.
2020, 83(7): 665-671
Abstract:
Three kinds of structure-symmetric thiourea catalysts containing multi-hydrogen bond with binol axial chiral were synthesized and successfully applied to the syntheses of 1, 4-dihydropyridine derivatives. The results showed that the synthesized polyhydrogen-bonded thioureas have better catalytic activity, which can effectively improve the yield and enantioselectivity of the 1, 4-dihydropyridine derivatives. All new compounds were characterized by 1H NMR、13C NMR、IR、melting point and so on.
Three kinds of structure-symmetric thiourea catalysts containing multi-hydrogen bond with binol axial chiral were synthesized and successfully applied to the syntheses of 1, 4-dihydropyridine derivatives. The results showed that the synthesized polyhydrogen-bonded thioureas have better catalytic activity, which can effectively improve the yield and enantioselectivity of the 1, 4-dihydropyridine derivatives. All new compounds were characterized by 1H NMR、13C NMR、IR、melting point and so on.
