Photochromism is a photoinduced reversible transformation in a chemical species between two isomers. Among many kinds of photochromic molecules, diarylethene derivatives are one of the representative systems undergoing photoinduced cyclization and cycloreversion reactions between open- and closed-ring isomers. The excellent thermal stability of both isomers and high fatigue resistance have been attracting much attention and a number of investigations have been reported for the change of physical and chemical properties accompanied with photochromic reactions. To acquire rational principles for the design of advanced systems, the elucidation of the detailed reaction profiles is crucially important. Along this line, in the preset work, we have investigated the excitation wavelength and temperature dependencies of photochromic reactions by means of steady-state measurements of reaction quantum yields and femtosecond transient absorption spectroscopy.
ジアリールエテン誘導体は、光誘起環開閉反応に基づくフォトクロミズムを示す化合物であり、両異性体の熱安定性、繰り返し耐久性などの優れた特性を多く有することから応用的観点からも注目されている。より優れた誘導体を設計するためには基礎的な反応機構の解明が重要である。そこで本研究では開環反応の詳細なダイナミクスとメカニズムの解明を目的として、数種の誘導体の環開閉反応に対し、定常光照射による反応収量およびフェムト秒ダイナミクスについて、溶媒、温度、励起波長依存性効果を測定した。