Distortional Supramolecular Isomers of Polyrotaxane Coordination Polymers: Photoreactivity and Sensing of Nitro Compounds

• Published in: Angewandte Chemie (International ed.) Vol. 53; no. 22; pp. 5591 - 5595
• Main Authors: Park, In-Hyeok, Medishetty, Raghavender, Kim, Ja-Yeon, Lee, Shim Sung, Vittal, Jagadese J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 26.05.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: [2+2] cycloaddition; Axles; Coordination polymers; Detection; Distortion; Isomers; Ligands; metal-organic frameworks; Nitro compounds; Polymers; polyrotaxanes; Spacers; Two dimensional; zinc; [2+2] cycloaddition; nitro compounds; polyrotaxanes; zinc; metal-organic frameworks
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201310536

Distortional isomers, or bond‐stretch isomers, differ only in the length of one or more bonds, which is due to crystallographic disorder in most cases. The term distortional isomerism is introduced to describe the structures of polyrotaxane 2D coordination polymers (CPs) that differ only by the relative positions in the neighboring entangled axles. A large ring and a long spacer ligand in 2D CPs yielded four different supramolecular isomers, of which two have an entangled polyrotaxane structure. One pair of CC bonds in the spacer ligand is well‐aligned in one isomer and undergoes [2+2] cycloaddition reaction, whereas the other isomer is photoinert. They also have different sensing efficiency for several aromatic nitro compounds. However, both isomers show selective PL quenching for the Brady’s reagent. Structurally similar supramolecular isomers with different photochemical reactivity and sensing abilities appear to be unprecedented. Polyrotaxane isomers! Of the four supramolecular isomers of coordination polymers synthesized, two have polyrotaxane structures that differ only in the relative positions of the wheel in the neighboring axle. They show different photoreactivity under UV light as well as sensing abilities of a number of organic nitro compounds.