Visible Light-Driven Artificial Molecular Switch Actuated by Radical鈥揜adical and Donor鈥揂cceptor Interactions

详细信息    查看全文

• 作者：Junling Sun ; Yilei Wu ; Zhichang Liu ; Dennis Cao ; Yuping Wang ; Chuyang Cheng ; Dongyang Chen ; Michael R. Wasielewski ; J. Fraser Stoddart
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：119
• 期：24
• 页码：6317-6325
• 全文大小：572K
• ISSN：1520-5215

文摘

We describe a visible light-driven switchable [2]catenane, composed of a Ru(bpy)₃²⁺ tethered cyclobis(paraquat-p-phenylene) (CBPQT⁴⁺) ring that is interlocked mechanically with a macrocyclic polyether consisting of electron-rich 1,5-dioxynaphthalene (DNP) and electron-deficient 4,4鈥?bipyridinium (BIPY²⁺) units. In the oxidized state, the CBPQT⁴⁺ ring encircles the DNP recognition site as a consequence of favorable donor鈥揳cceptor interactions. In the presence of an excess of triethanolamine (TEOA), visible light irradiation reduces the BIPY²⁺ units to BIPY^(鈥?) radical cations under the influence of the photosensitizer Ru(bpy)₃²⁺, resulting in the movement of the CBPQT^2(鈥?) ring from the DNP to the BIPY^(鈥?) recognition site as a consequence of the formation of the more energetically favorable trisradical complex, BIPY^(鈥?) 鈯?CBPQT^2(鈥?). Upon introducing O₂ in the dark, the BIPY^(鈥?) radical cations are oxidized back to BIPY²⁺ dications, leading to the reinstatement of the CBPQT⁴⁺ ring encircled around the DNP recognition site. Employing this strategy of redox control, we have demonstrated a prototypical molecular switch that can be manipulated photochemically and chemically by sequential reduction and oxidation.