Zn(II)-Dipicolylamine-Attached Amphiphilic Polythiophene for Quantitative Pattern Recognition of Oxyanions in...

Herein, we propose a novel amphiphilic polythiophene-based chemosensor functionalized with a Zn(II)-dipicolylamine side chain (1_poly  ⋅ Zn) for the pattern recognition of oxyanions. Optical changes in amphiphilic 1_poly  ⋅ Zn can be induced by the formation of a random coil from a backbone-planarized structure upon the addition of target oxyanions, which results in blueshifts in the UV-vis absorption spectra and turn-on-type fluorescence responses. Dynamic behavior in a polythiophene wire and/or among wires could be a driving force for obtaining visible color changes, while the molecular wire effect is dominant in obtaining fluorescence sensor responses. Notably, the magnitude of optical changes in 1_poly  ⋅ Zn has depended on differences in properties of oxyanions, such as their binding affinity, hydrophilicity, and molecular geometry. Thus, various colorimetric and fluorescence response patterns of 1_poly  ⋅ Zn to oxyanions were obtained, albeit using a single chemosensor. A constructed information-rich dataset was applied to pattern recognition for the simultaneous group categorization of phosphate and carboxylate groups and the prediction of similar structural oxyanions at a different order of concentrations in their mixture solutions.