Using Fe, Co or Ni chains as electrodes, we designed several annulene-based molecular spintronic devices and investigated the quantum transport properties based on density functional theory and non-equilibrium Green＇...Using Fe, Co or Ni chains as electrodes, we designed several annulene-based molecular spintronic devices and investigated the quantum transport properties based on density functional theory and non-equilibrium Green＇s function method.Our results show that these devices have outstanding spin-filter capabilities and exhibit giant magnetoresistance effect,and that with Ni chains as electrodes, the device has the best transport properties. Furthermore, we investigated the spinpolarized optoelectronic properties of the device with Ni electrodes and found that the spin-polarized photocurrents can be directly generated by irradiating the device with infrared, visible or ultraviolet light. More importantly, if the magnetization directions of the two electrodes are antiparallel, the photocurrents with different spins are spatially separated, appearing at different electrodes. This phenomenon provides a new way to simultaneously generate two spin currents.展开更多
Xia and coworkers[1]have synthesized a novel class of organometallic molecules that has a metal-centered planar annulene framework(Scheme 1).These unprecedented compounds have potential applications in electronics,pho...Xia and coworkers[1]have synthesized a novel class of organometallic molecules that has a metal-centered planar annulene framework(Scheme 1).These unprecedented compounds have potential applications in electronics,photonics,and catalysis,as well as building blocks in materials science.展开更多
Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease ...Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease of topomerization is dependent on the charge distribution and planarity of the ground state and the transition state of 9-membered rings as well as the size and electronegativity of halogen substituent. Consequently, the endo-2-halo-[9] annulen anion topomers become unstable and easily convert to related exo-topomers. Hence, according to the DFT calcu- lations, the order of topomerization energy barrier for endo = exo topomerization is lendo 〉 2endo 〉 3endo.展开更多
Metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)represent two dominant kinds of reticular materials.Mutual chemical conversion of these two species,however,still remains unreported.Herein,the reacti...Metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)represent two dominant kinds of reticular materials.Mutual chemical conversion of these two species,however,still remains unreported.Herein,the reaction of a two-dimensional MOF,Ni_(3)(HITP)_(2)(HITP=2,3,6,7,10,11-hexaiminotriphenylene),with 1,1,3,3-tetramethoxypropane induces the cyclization transformation of partial bis(diimine)nickel coordination subunits to tetraaza[14]annulene(TAA)metallomacrocycle moieties.A hemi-covalent organic framework,P-Ni_(3)(TAA)_(3),with different conversion efficiencies(P)of 34-72%for bis(diimine)nickel units depending on the reaction time has been obtained and preserves permanent porosity and crystallinity.The corresponding time-dependent conversion has been assessed by FT-IR spectroscopy,XPS,SEM,TEM,and powder X-ray diffraction analyses.In comparison with Ni_(3)(HITP)_(2),40%-Ni_(3)(TAA)_(3) exhibits improved chemical stability under acidic conditions and significantly enhanced catalytic properties towards the photocatalytic CO_(2) reduction.This result will be surely helpful in mutual investigations covering both MOFs and COFs.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.U1510132,U1610255,51401142,and 11604235)the Key Innovative Research Team in Science and Technology of Shanxi Province,China(Grant No.201605D131045-10)+2 种基金the Natural Science Foundation of Shanxi Province,China(Grant Nos.2015021027 and 2016021030)the Scientific and Technological Innovation Program of the Higher Education Institutions of Shanxi Province,China(Grant No.2016140)the Program for the Outstanding Innovative Teams of the Higher Learning Institutions of Shanxi Province,China
文摘Using Fe, Co or Ni chains as electrodes, we designed several annulene-based molecular spintronic devices and investigated the quantum transport properties based on density functional theory and non-equilibrium Green＇s function method.Our results show that these devices have outstanding spin-filter capabilities and exhibit giant magnetoresistance effect,and that with Ni chains as electrodes, the device has the best transport properties. Furthermore, we investigated the spinpolarized optoelectronic properties of the device with Ni electrodes and found that the spin-polarized photocurrents can be directly generated by irradiating the device with infrared, visible or ultraviolet light. More importantly, if the magnetization directions of the two electrodes are antiparallel, the photocurrents with different spins are spatially separated, appearing at different electrodes. This phenomenon provides a new way to simultaneously generate two spin currents.
文摘Xia and coworkers[1]have synthesized a novel class of organometallic molecules that has a metal-centered planar annulene framework(Scheme 1).These unprecedented compounds have potential applications in electronics,photonics,and catalysis,as well as building blocks in materials science.
文摘Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease of topomerization is dependent on the charge distribution and planarity of the ground state and the transition state of 9-membered rings as well as the size and electronegativity of halogen substituent. Consequently, the endo-2-halo-[9] annulen anion topomers become unstable and easily convert to related exo-topomers. Hence, according to the DFT calcu- lations, the order of topomerization energy barrier for endo = exo topomerization is lendo 〉 2endo 〉 3endo.
基金support from the Natural Science Foundation of China(No.22175020,22131005,22072004,21631003)the Fundamental Research Funds for the Central Universities(No.FRF-BD-20-14A)University of Science and Technology Beijing is gratefully acknowledged.
文摘Metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)represent two dominant kinds of reticular materials.Mutual chemical conversion of these two species,however,still remains unreported.Herein,the reaction of a two-dimensional MOF,Ni_(3)(HITP)_(2)(HITP=2,3,6,7,10,11-hexaiminotriphenylene),with 1,1,3,3-tetramethoxypropane induces the cyclization transformation of partial bis(diimine)nickel coordination subunits to tetraaza[14]annulene(TAA)metallomacrocycle moieties.A hemi-covalent organic framework,P-Ni_(3)(TAA)_(3),with different conversion efficiencies(P)of 34-72%for bis(diimine)nickel units depending on the reaction time has been obtained and preserves permanent porosity and crystallinity.The corresponding time-dependent conversion has been assessed by FT-IR spectroscopy,XPS,SEM,TEM,and powder X-ray diffraction analyses.In comparison with Ni_(3)(HITP)_(2),40%-Ni_(3)(TAA)_(3) exhibits improved chemical stability under acidic conditions and significantly enhanced catalytic properties towards the photocatalytic CO_(2) reduction.This result will be surely helpful in mutual investigations covering both MOFs and COFs.
