Unsymmetric Bistable [c2]Daisy Chain Rotaxanes which Combine Two Types of Electroactive Stoppers

• Published in: European journal of organic chemistry Vol. 2019; no. 21; pp. 3421 - 3432
• Main Authors: Wolf, Adrian, Cid, Juan‐José, Moulin, Emilie, Niess, Frédéric, Du, Guangyan, Goujon, Antoine, Busseron, Eric, Ruff, Adrian, Ludwigs, Sabine, Giuseppone, Nicolas
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 10.06.2019; Wiley Subscription Services, Inc; Wiley-VCH Verlag
• Subjects: Actuation; Buses; Chains; Chemical Sciences; Chemistry; Chemistry, Organic; Electroactive; Electrochemical analysis; NMR; Nuclear magnetic resonance; Organic chemistry; Perylene; Physical Sciences; PH‐Responsive; Polymers; Rotaxanes; Science & Technology; Shafts (machine elements); Triarylamine; POLYMERS; ENERGY; Rotaxanes; SUPRAMOLECULAR ORGANIC NANOWIRES; 1,6-REGIOISOMERS; CONSTRUCTION; PH; Triarylamine; PH-Responsive; Perylene; SEPARATION; ACTUATORS; Electroactive
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201900179

Mechanically interlocked molecules (MIMs) have emerged as intriguing building blocks for the construction of stimuli‐responsive devices and materials. A particularly interesting and well‐implemented subclass of MIMs is composed of symmetric bistable [c2]daisy chain rotaxanes. Topologically, they consist in the double thread of two symmetric macrocycles that are covalently linked to an axle bearing two switchable stations and a bulky stopper to avoid unthreading. Herein we report the synthesis and characterization of a series of unsymmetric bistable [c2]daisy chain rotaxanes that present two different electroactive units as stoppers (an electron donor triarylamine and an electron acceptor perylene bisimide unit). Using a combination of 1D and 2D NMR along with cyclic voltammetry, we demonstrate that the pH actuation of the mechanical bond can be used to modulate the electrochemical properties of the bistable [c2]daisy chain rotaxanes when switching between the contracted and extended forms. pH‐Switchable [c2]daisy chain rotaxanes that present two different electroactive units as stoppers have been synthesized and fully characterized. Their actuation between the contracted and extended forms leads to a modification of their electrochemical properties.