Creation of Novel Mechanochromic Amorphous Molecular Materials and Proposal of a Method for Evaluating the Degree of Amorphization

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05625
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 35030:Organic functional materials-related
• Research Institution: Muroran Institute of Technology
• Principal Investigator: NAKANO Hideyuki 室蘭工業大学, 大学院工学研究科, 教授 (00222167)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: メカノクロミック発光材料 / アモルファス分子材料 / 発光量子収率 / 蛍光寿命 / アモルファス化度 / 光化学反応

Outline of Final Research Achievements

Novel series of emitting amorphous molecular materials possessing cyanostilbene and anthracene skeletons were designed and synthesized, and their emission properties in various states were investigated. They were found to exhibit mechanochromic emission based on the amorphization of crystals by grinding. We also found that the cyanostilbene-based amorphous molecular materials did not show any photochemical reactions in their crystalline states, whereas photocycloaddition reactions proceeded in their amorphous films. In addition, the photoreactivity in the amorphous film obtained by grinding was found to be lower than that in the spin-coated film, suggesting that some molecular orientations in the crystal was maintained in the ground film.

Free Research Field

有機機能材料化学

Academic Significance and Societal Importance of the Research Achievements

分子間光環化二量化反応が可能な新規発光性アモルファス分子材料を創出し、これらのアモルファス膜の光反応性が膜作製法に依存していることを明らかにすることで、これまで議論されてこなかった低分子系アモルファス材料のアモルファス化度を評価する手法の一つを提案することが出来た。また、結晶を摩砕するとアモルファス化することに基づいて発光色が変化するメカノクロミック特性について、摩砕によって完全に分子配向を乱れさせなくても充分な発光スペクトル変化を示すことを明らかにし、メカノクロミック発光特性の定量的な議論に向けて道筋をつけることができた。