Manipulating symmetry-breaking charge separation employing molecular recognition

Zhao, Xueze; Young, Ryan M.; Tang, Chun; Wu, Guangcheng; Peinkofer, Kathryn R.; Han, Yaoyao; Yang, Shuliang; Xing, Yi-Kang; Han, Han; Wu, Huang; Li, Xuesong; Feng, Yuanning; Zhang, Ruihua; Stern, Charlotte L.; Wasielewski, Michael R.; Stoddart, J. Fraser

doi:10.1016/j.chempr.2024.07.010

DOE OSTI · 3014153

Manipulating symmetry-breaking charge separation employing molecular recognition

Zhao, Xueze·Young, Ryan M.·Tang, Chun·Wu, Guangcheng·Peinkofer, Kathryn R.·Han, Yaoyao·Yang, Shuliang·Xing, Yi-Kang·Han, Han·Wu, Huang·Li, Xuesong·Feng, Yuanning·Zhang, Ruihua·Stern, Charlotte L.·Wasielewski, Michael R.·Stoddart, J. Fraser

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Abstract

The exploration of symmetry-breaking charge separation (SB-CS) is imperative when designing functional light-harvesting materials. Past explorations, however, have been confined to covalent systems, more often than not requiring complicated/demanding syntheses and facing inconvenient regulation of charge transfer processes. Here, in this work, we present a concept that regulates the efficiency of SB-CS through molecular recognition utilizing a pyridinium-based cyclophane as a host. This host undergoes photo-driven excited-state SB-CS. By employing different guests with distinct frontier molecular orbital energy levels, we have achieved comprehensive control of electron transfer pathways in the cyclophane, modulating between accelerated (>10-fold) intramolecular SB-CS involving superexchange and direct intermolecular electron transfer between the host and guest. The improvement in SB-CS efficiency results in catalytic activity for the photo-oxidation of a sulfur-mustard simulant. This research offers an opportunity for tuning SB-CS by utilizing molecular recognition, which holds the potential for achieving precise regulation without complicated organic syntheses.

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Zhao, Xueze, Young, Ryan M., Tang, Chun, Wu, Guangcheng, Peinkofer, Kathryn R., Han, Yaoyao, Yang, Shuliang, Xing, Yi-Kang, Han, Han, Wu, Huang, Li, Xuesong, Feng, Yuanning, Zhang, Ruihua, Stern, Charlotte L., Wasielewski, Michael R., Stoddart, J. Fraser. 2024-08-09. Manipulating symmetry-breaking charge separation employing molecular recognition. https://doi.org/10.1016/j.chempr.2024.07.010

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