2002 Fiscal Year Final Research Report Summary
Direct observation of molecular chirality and molecular reaction on solid surface
| Project/Area Number |
13640551
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Inorganic chemistry
|
|---|
| Research Institution | Kanazawa Institute of Technology |
|---|
Principal Investigator |
TANIGUCHI Masahiro Kanazawa Institute of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (30250418)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YAMAGISHI Akihiko The University of Tokyo, Graduate School of Sciences, Professor, 大学院・理学研究科, 教授 (70001865)
NISHIKAWA Osamu Kanazawa Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (10108235)
|
|---|
| Project Period (FY) |
2001 – 2002
|
| Keywords | scanning tunneling microscopy / solid surface / gold surface / molecular chirality / optical activity / molecular recognition / thin film / helicene |
|---|
| Research Abstract |
Pasteur's discovery of spontaneous resolution of the sodium ammonium tartaric acid introduced the basic idea of chirality into chemistry. The microscope of his age helped him to distinguish the outlook of two enantiomorphous crystals one by one. Since then, the development of the scanning probe microscope (SPM), such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM), made it possible to image not only the asymmetry of the crystal lattices but also individual molecules. In this work, the molecular recognition based on chirality was elucidated. Monolayers of hexathia[11]heterohelicene ([11]TH), which consists of 5 benzene rings and 6 thiophene rings were prepared on gold substreates under 1 UHV condition. [11]TH has a bulky structure of helically annulated aromatic rings which is suitable for imaging of molecular chirality. [11]TH was used in racemic form in this work. Low energy electron diffraction (LEED) and STM were used for the structural study of the monolayers. [11]TH monolayer on gold(111) substrate showed the same structure as on (111) analogue of polycrystalline surface. It showed six-fold symmetry lattice which suggested no chiral recognition between molecules. The image taken on the terrace top demonstrated the chirality imaging of individual molecule in the racemic glass phase. [11]TH evaporated on gold(110) showed loosely packed molecular chains. But the chains of [11]TH gave no distinctive sign of chiral interaction. On the other hand, the arrays formed on the step bunching region of polycrystal surface showed the isomorphic chiral chains. The results suggested that the substrate structure affected the spacing and configuration of the adsorbed molecules. And these two factors determined the contribution of the chirality of the adsorbates to the monolayer structure.
|
