Ion-Specific Aggregation in Conjugated Polymers: Highly Sensitive and Selective Fluorescent Ion Chemosensors

Two polymer chains are forced into contact by 2:1 sandwich complex formation between K+ ions and [15]crown-5 groups. By controlling the steric bulk of the side groups of the repeating units and the distance between [15]crown-5 groups on the polymer main chain (see picture) the interpolymer interactions induced by K+ ions can be tuned. Four poly(p-phenylene ethynylene)s with [15]crown-5 side groups were prepared, two of which were designed to function as potassium sensory materials.