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二维MXene材料CrVCF_(2)的电子性质和磁性的第一性原理研究
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作者 刘晓莹 黄海深 +2 位作者 孙丽 潘孟美 尚真真 《人工晶体学报》 CAS 北大核心 2024年第8期1386-1393,共8页
采用基于密度泛函理论的第一性原理研究了—F官能团对Janus型MXene二维材料CrVC的结构、电子性质和磁性的影响。计算结果表明,—F官能团改变了CrVC的电子性质和磁性,CrVCF_(2)的9种可能结构的基态是铁磁态,其中CrVCF_(2)-33结构的能量最... 采用基于密度泛函理论的第一性原理研究了—F官能团对Janus型MXene二维材料CrVC的结构、电子性质和磁性的影响。计算结果表明,—F官能团改变了CrVC的电子性质和磁性,CrVCF_(2)的9种可能结构的基态是铁磁态,其中CrVCF_(2)-33结构的能量最低,是最为稳定的基态结构,其磁矩为5.01μ_(B),带隙为0.099 eV,具有半导体特性。在施加-4%~+4%的双轴拉伸与压缩应变时,CrVCF_(2)-33的总磁矩保持不变;能量随着压缩或拉伸应变的增大而变大,但变化的幅度低于0.2 eV;带隙在应变的作用下会发生改变,当拉伸应变为2.4%时,带隙减小到0.005 eV,接近于零,可看作是自旋零带隙半导体。由此可知,适度的应变可调节CrVCF_(2)材料的电子能带结构,甚至可形成自旋零带隙半导体,这在自旋电子学领域具有潜在的应用价值。 展开更多
关键词 第一性原理 MXene材料 —f官能团 电子结构 磁性 应变
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Visible-light photoredox-catalyzed selective carboxylation of C(sp~2)-F bonds in polyfluoroarenes with CO2
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作者 Zhi‐Yu Bo Si‐Shun Yan +6 位作者 Tian‐Yu Gao Lei Song Chuan‐Kun Ran Yi He Wei Zhang Guang‐Mei Cao Da‐Gang Yu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第9期2388-2394,共7页
Visible light‐driven carboxylation with CO_(2) have emerged as a sustainable and powerful way to transfer waste to treasure.However,it is still challenging for aryl fluorides due to the low reactivities of both C(sp2... Visible light‐driven carboxylation with CO_(2) have emerged as a sustainable and powerful way to transfer waste to treasure.However,it is still challenging for aryl fluorides due to the low reactivities of both C(sp2)−F bonds and CO_(2).Herein,we report the first photocatalytic carboxylation of aryl C−F bonds with CO_(2).The visible‐light photoredox catalysis enables selective carboxylation of strong C(sp2)−F bonds in diverse polyluoroarenes,such as penta‐,tetra‐,and tri‐fluoroarenes under mild conditions,providing a facile access to a series of important polyfluoroaryl carboxylic acids with good yields.In contrast to previous reports of direct capture of polyfluoroaryl radicals,mechanistic studies suggest that the reduction of fleeting polyfluoroaryl radicals into polyfluoroaryl anions might be involved in this transformation,which may open a new avenue for photocatalytic functionalization of aryl C−F bonds. 展开更多
关键词 Carbon dioxide Visible-light photoredox catalysis CARBOXYLATION C-f functionalization POLYfLUOROARENES
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