本文利用低温扫描隧道显微镜(low temperature scanning tunneling microscopy,LT-STM)研究了四联苯分子在半金属Bi(111)表面上的超分子手性及其自组装结构。在极低的覆盖度下,四联苯分子形成纳米尺度的分子团簇,团簇中的分子有平躺和...本文利用低温扫描隧道显微镜(low temperature scanning tunneling microscopy,LT-STM)研究了四联苯分子在半金属Bi(111)表面上的超分子手性及其自组装结构。在极低的覆盖度下,四联苯分子形成纳米尺度的分子团簇,团簇中的分子有平躺和侧躺的取向。随着覆盖度的增加,四联苯分子形成多畴的自组装单层结构。自组装单层的基本结构单元是由两个平躺分子和一个侧躺分子构成的三聚体。高分辩的STM图表明,平躺的四联苯分子表现出结构对称性,而侧躺的四联苯分子表现为四个之字形的突起,表明四个苯环之间发生了扭曲,使得三聚体团簇具有超分子手性。有趣的是,在畴区内部相邻两个三聚体的手性相反;在畴界两侧两个三聚体的手性相同,表明同手性的三聚体之间存在空间位阻作用。当覆盖度增加到一个满层,畴界不复存在,整个分子单层形成长程有序的消旋结构。此外,由于分子与半金属衬底之间较弱的相互作用,无论是侧躺的分子还是平躺的分子,都会受到针尖电场的影响发生移动或转动。上述研究结果为理解四联苯分子和半金属之间的相互作用,超分子手性和分子自组装结构之间的关联,以及制备长程有序的界面结构提供了重要信息。展开更多
In this review we describe a family of organic-based host frameworks which can accommodate guest molecules. The aim of the study is to test the adjustability of this class of mimic structures that may lead to new inte...In this review we describe a family of organic-based host frameworks which can accommodate guest molecules. The aim of the study is to test the adjustability of this class of mimic structures that may lead to new interesting functions. Emphasis of our research is placed upon four aspects: 1) thermal properties, 2) surface photochemistry, 3) fullerene adsorption, and 4) guest inclusion. It is envisioned that such approach of nanoporous molecular networks might be developed into a new family of useful soft frameworks for studies toward shape-selective catalysis, molecular recognition, self-assembly, and host-guest supramolecular chemistry.展开更多
文摘本文利用低温扫描隧道显微镜(low temperature scanning tunneling microscopy,LT-STM)研究了四联苯分子在半金属Bi(111)表面上的超分子手性及其自组装结构。在极低的覆盖度下,四联苯分子形成纳米尺度的分子团簇,团簇中的分子有平躺和侧躺的取向。随着覆盖度的增加,四联苯分子形成多畴的自组装单层结构。自组装单层的基本结构单元是由两个平躺分子和一个侧躺分子构成的三聚体。高分辩的STM图表明,平躺的四联苯分子表现出结构对称性,而侧躺的四联苯分子表现为四个之字形的突起,表明四个苯环之间发生了扭曲,使得三聚体团簇具有超分子手性。有趣的是,在畴区内部相邻两个三聚体的手性相反;在畴界两侧两个三聚体的手性相同,表明同手性的三聚体之间存在空间位阻作用。当覆盖度增加到一个满层,畴界不复存在,整个分子单层形成长程有序的消旋结构。此外,由于分子与半金属衬底之间较弱的相互作用,无论是侧躺的分子还是平躺的分子,都会受到针尖电场的影响发生移动或转动。上述研究结果为理解四联苯分子和半金属之间的相互作用,超分子手性和分子自组装结构之间的关联,以及制备长程有序的界面结构提供了重要信息。
基金Financial support from the National Natural Science Foundation of China (Grant Nos. 20473097 and 20573116)the National Key Project for Basic Research (Grant Nos. 2007CB936503 and 2007CB936802)
文摘In this review we describe a family of organic-based host frameworks which can accommodate guest molecules. The aim of the study is to test the adjustability of this class of mimic structures that may lead to new interesting functions. Emphasis of our research is placed upon four aspects: 1) thermal properties, 2) surface photochemistry, 3) fullerene adsorption, and 4) guest inclusion. It is envisioned that such approach of nanoporous molecular networks might be developed into a new family of useful soft frameworks for studies toward shape-selective catalysis, molecular recognition, self-assembly, and host-guest supramolecular chemistry.
