This work studies the angle dependence of the interactions between impinging CH2 particles of 150 eV with the tungsten surface. The simulations show that the carbon atoms are much more easily bonded to the tungsten at...This work studies the angle dependence of the interactions between impinging CH2 particles of 150 eV with the tungsten surface. The simulations show that the carbon atoms are much more easily bonded to the tungsten atoms than hydrogen atoms, though a few of the latter can also penetrate into the tungsten material. When the incidence angle is greater than 75%, the incident CH2 particles are reflected without break-ups. Below this angle, a W-C layer of about 0.5 nm is formed with another C, H-rich layer depositing on top of it. The molecular dynamics （MD） approach has proved to be a powerful tool to solve the structural problems at atomic length scale of various materials. Some of its possible applications to the railway track materials have also been discussed.展开更多
Making full use of coordination-driven self-assembly strategy,we herein described the selective synthesis of a molecular Borromean rings and two cases of “U”-shaped tweezer-like molecular assemblies in high yield by...Making full use of coordination-driven self-assembly strategy,we herein described the selective synthesis of a molecular Borromean rings and two cases of “U”-shaped tweezer-like molecular assemblies in high yield by using bipyridyl ligands based on biphenyl unit and half-sandwich binuclear rhodium(III)/iridium(III) building blocks.The selective synthesis was realized by adjusting the length of dipyridyl arms.The utilization of curved U-shaped bipyridyl ligand L1 led to tweezer-like molecular assemblies.Subsequently,olefinic bonds were introduced to elongate dipyridyl arms obtaining ligand L2.The ligand L2 has two stable conformations,U-shape and Z-shape,which facilitated the formation of different topologies including the tetranuclear macrocycle and Borromean rings with different building blocks in this work.These structures in solid and solution all have been further confirmed by single-crystal X-ray diffraction,NMR analysis,and mass spectrometry.In addition,as an important driving force,π-π stacking interactions not only played a significant role in the stability of structures but also further triggered photothermal conversion in solution.The experimental results demonstrated that compounds 1a and 2 had good NIR photothermal conversion efficiency (11.83% and 17.76%),and further analysis found the photothermal conversion efficiency had a gradual increase in the trend with the π-π stacking interactions increasing.This research expands the application of topological structures in materials science and provides a new idea for the synthesis of novel photothermal conversion materials.展开更多
The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,espec...The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of guests,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.展开更多
基金financially supported by the Science Foundation for International Cooperation of Sichuan Province (2014HH0016)the Fundamental Research Funds for the Central Universities (SWJTU2014: A0920502051113-10000)National Magnetic Confinement Fusion Science Program (2011GB112001)
文摘This work studies the angle dependence of the interactions between impinging CH2 particles of 150 eV with the tungsten surface. The simulations show that the carbon atoms are much more easily bonded to the tungsten atoms than hydrogen atoms, though a few of the latter can also penetrate into the tungsten material. When the incidence angle is greater than 75%, the incident CH2 particles are reflected without break-ups. Below this angle, a W-C layer of about 0.5 nm is formed with another C, H-rich layer depositing on top of it. The molecular dynamics （MD） approach has proved to be a powerful tool to solve the structural problems at atomic length scale of various materials. Some of its possible applications to the railway track materials have also been discussed.
基金supported by the National Natural Science Foundation of China(Nos.22031003,21720102004)the Shanghai Science Technology Committee(No.19DZ2270100)G.-X.J.thanks the Alexander von Humboldt Foundation for a Humboldt Research Award.
文摘Making full use of coordination-driven self-assembly strategy,we herein described the selective synthesis of a molecular Borromean rings and two cases of “U”-shaped tweezer-like molecular assemblies in high yield by using bipyridyl ligands based on biphenyl unit and half-sandwich binuclear rhodium(III)/iridium(III) building blocks.The selective synthesis was realized by adjusting the length of dipyridyl arms.The utilization of curved U-shaped bipyridyl ligand L1 led to tweezer-like molecular assemblies.Subsequently,olefinic bonds were introduced to elongate dipyridyl arms obtaining ligand L2.The ligand L2 has two stable conformations,U-shape and Z-shape,which facilitated the formation of different topologies including the tetranuclear macrocycle and Borromean rings with different building blocks in this work.These structures in solid and solution all have been further confirmed by single-crystal X-ray diffraction,NMR analysis,and mass spectrometry.In addition,as an important driving force,π-π stacking interactions not only played a significant role in the stability of structures but also further triggered photothermal conversion in solution.The experimental results demonstrated that compounds 1a and 2 had good NIR photothermal conversion efficiency (11.83% and 17.76%),and further analysis found the photothermal conversion efficiency had a gradual increase in the trend with the π-π stacking interactions increasing.This research expands the application of topological structures in materials science and provides a new idea for the synthesis of novel photothermal conversion materials.
基金supported by the National Nature Science Foundation of China(grant nos.21871266,21731006,and 21403241)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB20000000)+1 种基金Key Research Program of Frontier Science CAS(grant no.QYZDY-SSW-SLH025)Youth Innovation Promotion Association CAS.
文摘The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of guests,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.
