Organometallic Rotaxane Dendrimers with Fourth-Generation Mechanically Interlocked Branches
Organometallic rotaxane dendrimers with fourth-generation mechanically interlocked branches Wei Wanga, Li-Jun Chena, Xu-Qing Wanga, Bin Suna,b, Xiaopeng Lib, Yanyan Zhangc, Jiameng Shic, Yihua Yuc, Li Zhangd, Minghua Liud, and Hai-Bo Yanga,1 aShanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062, People’s Republic of China; bDepartment of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666; cShanghai Key Laboratory of Magnetic Resonance, Department of Physics, East China Normal University, Shanghai 200062, People’s Republic of China; and dKey Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080, People’s Republic of China Edited by Vivian Wing-Wah Yam, The University of Hong Kong, Hong Kong, China, and approved March 31, 2015 (received for review January 11, 2015) Mechanically interlocked molecules, such as catenanes, rotaxanes, Herein, we describe the synthesis, characterization, and func- and knots, have applications in information storage, switching tionalization of higher-generation (up to fourth-generation) organ- devices, and chemical catalysis. Rotaxanes are dumbbell-shaped ometallic rotaxane branched dendrimers. A divergent strategy was molecules that are threaded through a large ring, and the relative employed for the dendrimer synthesis in which the host–guest motion of the two components along each other can respond to complex of a pillar[5]arene and a neutral alkyl chain were used as external stimuli. Multiple rotaxane units can amplify responsiveness, the rotaxane subunits. The formation of platinum–acetylide bonds — — and repetitively branched molecules dendrimers can serve as vehi- wasthegrowthstepinthesynthesis;it produced satisfactory yields cles for assembly of many rotaxanes on single, monodisperse com- and allowed construction of the targeted structures.
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