Formation of Functional Cyclooctadiene Derivatives by Supramolecularly- Controlled Topochemical Reactions and Their Use as Highly Selective Fluorescent Biomolecule Probes†

Summary of main observation and conclusion Controlling the regio- and stereochemistry of the photoproducts in solution is far more challenging for polyenes than for monoalkenes. Herein, a supramolecularly-controlled topochemical reaction of conjugated dienes in homogeneous system is developed, ultimately providing two cyclooctadiene-cored tetraimidazolium molecular receptors exclusively. These cyclooctadiene derivatives exhibited highly sensitive and selective fluorescence sensing for thymine relative to other biologically relevant species in aqueous solution at physiological pH. Both the cyclooctadiene moieties and imidazolium units play important roles in the selective recognition observed. The presented supramolecularly-controlled method allows the simple yet rare selective photoconversion of flexible cyclooctadiene derivatives in solution. This study offers a new synthetic strategy for the preparation of functional molecules with potential for use in biological applications.