Novel Polythreaded Coordination Polymer: from an Armed-Polyrotaxane Sheet to a 3D Polypseudorotaxane Array, Photo- and Thermochromic Behaviors

A novel polythreaded coordination network having both polyrotaxane and polypseudorotaxane characters was synthesized by using a flexible redox-active viologen derivative. Interestingly, a sandwich-type donor-acceptor-donor stacking is formed within each ring as a consequence of both types of polythreading in this species, and photoinduced and thermal-induced reduction of bipyridinium occurs with a color change from yellow to blue.