2019 Fiscal Year Final Research Report
Studies on spontaneous enantiomeric resolution by conformational change induced external stimuli
| Project/Area Number |
17K05834
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Research Field |
Functional solid state chemistry
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2017-04-01 – 2020-03-31
|
| Keywords | 光学分割 / 相転移 / 結晶多形 / 結晶化 / 光異性化 |
|---|
| Outline of Final Research Achievements |
Preferential enrichment (PE) is a spontaneous enantiomeric resolution phenomenon that is caused by the polymorphic transition of a metastable form into a thermodynamically more stable one during crystallization from a highly supersaturated solution．We have found a new compound showing an excellent PE. The new mechanism was proposed to involve spontaneous disintegration of metastable crystals, followed by selective dissolution of excess homochiral molecules from the brittle deposited crystals during crystallization.
Azobenzenes are one of the most important classes of chromophores that undergo trans-to-cis photoisomerization. Azobenzenes were used to investigate spontaneous disintegration of metastable crystals during crystallization under UV conditions by using ATR-FTIR and in situ PXRD measurements. One of azobenzene derivatives crystallized under UV conditions at low temperature. The PXRD pattern of UV conditions was different from that of simulated from single crystal data.
|
| Free Research Field |
構造有機化学
|
| Academic Significance and Societal Importance of the Research Achievements |
結晶中での光を照射して分子構造が変化する反応（光異性化）の追跡や分子構造の変化に伴う相転移の過程を観察した例は数多く報告されているが，光反応で異性化をする分子が溶液中から結晶を形成の過程についての観測は，過去に例がなかった．今回，溶液中での温度可変粉末X線回折のその場測定によって，光異性化した分子（不安定構造を持つ分子）が，低温下で結晶として析出する過程を観察した．また溶液の温度を昇温すると相転移が起こることを見いだし，その過程の観察にも成功した．不安定化学種の結晶化過程の観察法の確立は学術的に大きな意味を持つ．この観測法によって，固体物性の大きな影響を与える結晶多形の検索に応用が可能である．
|
