High-Performance Photochromic Diarylethene with a Boron-Nitrogen Heterocyclic Ethene Bridge

Photochromic diarylethene molecules are promising candidates for applications in optical data storage devices. However, many reported diarylethene compounds suffer from inefficiencies due to low photocyclization quantum yields or poor fatigue resistance. To address this issue, we have developed a highly efficient boron-nitrogen heterocycle-bridged diarylethene. The bulky boron-nitrogen heterocyclic ethene bridge blocks interconversion between parallel and anti-parallel conformations, yielding two separated rotamers. Evaluation of their photochromic properties demonstrated that the anti-parallel conformer exhibits a high photocyclization quantum yield (Φ_o-c, 89.2%), excellent thermodynamic stability at 298 K and moderate fatigue resistance in hexane. Furthermore, direct comparison with its isosteric carbonaceous analog revealed that incorporating the azaborine moiety into the diarylethene scaffold significantly enhances its photochromic performance. This work presents a strategy that employs azaborine chemistry for the development of potential diarylethene-based photoswitchable materials.