Design and synthesis of metal ion-recognition-induced conjugated polymers: An approach to metal ion sensory materials

The synthesis and metal ion responsive properties of two 2,2'-bipyridyl-phenylene-vinylene-based polymers is reported. These polymers are designed to be partially conjugated in their metal-free state and fully conjugated when exposed to metal ions so that the ion-induced conjugation enhancement can be transduced into a measurable signal. It is found that these polymers exhibit highly ionochromic effects with a wide variety of transition and main group metal ions excluding metal ions of the alkali and alkaline earth groups. For instance, both absorption and fluorescence emission bands of the polymers upon exposure to metal ions can be red-shifted up to 120 nm, depending on the metal ions present and the polymers used.