Exploration on conjugated double helix molecules: control of the photophysical properties and dynamics

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05463
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: Kyoto University
• Principal Investigator: Tanaka Takayuki 京都大学, 工学研究科, 准教授 (20705446)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 二重らせん分子 / 動的平衡 / X線結晶構造解析 / 置換基効果 / 互変異性 / 錯体 / 溶媒効果 / 近赤外光吸収

Outline of Final Research Achievements

Dianlinotripyrrins are linear conjugated chains composed of terminal aniline moiety and tripyrrin core. This molecule can form a double helical structure by interstrand hydrogen bonding in non-polar solvent or in the solid state.
We have investigated the substituent effects on their dimerization association constant. Benzylamino-substituted tripyrrin showed smaller association constant, but accidentally a co-crystal of single and double strand molecules was obtained. Further, Induced CD spectra were observed with chiral amine-substituted tripyrrins. Dianilinotripyrrins bearing various meso-aryl substituents were studied. Introduction of methoxy or trifluoromethyl groups on the meso-aryl groups did not strongly affect the association constant, while tripyrrins bearing bulky meso-aryl substituents was prone to show smaller association constant. In addition, pentafluorophenyl substituted dianilinotripyrrin displayed different dimerization aptitude with longer pai-pai distances.

Free Research Field

有機化学

Academic Significance and Societal Importance of the Research Achievements

ジアニリノトリピリンは、超分子相互作用によりパイ共役二重らせんを形成する珍しいモチーフであるが、その置換基効果を詳細に検討可能であるという点で学術的に価値がある。溶液中での会合定数の決定に加え、X線結晶構造解析を用いた固体状態の解析により、二量体の形成に本質的に重要な要素を見出すことができた。こういった知見を生かしてジアニリノトリピリン特有の物性を見出しそれをセンサーやホストゲスト化学に用いることで、さらに社会的意義が高まることであろう。分子の非対称化や金属イオン認識などの研究にも展開可能であり、今後ますます魅力的な成果が期待できる研究領域であると考えている。