Multifunctional diphenyl ether-based, cross-linked polyisocyanide for efficient iodine capture and NO2-/SO3(2-)electrochemical probing

Compared with the extensively reported Schiff base-type polyimine (their backbones are connected by -C--N- bond) porous organic polymers (POPs), there are rare reports regarding the exploration of polyisocyanide (PIC)based, C1-type polyimine POPs. Herein, a kind of diphenyl ether-based, cross-linked PIC derivative (POBI) was successfully prepared. Fundamental properties of POBI as chemical structure, morphology, porosity, and thermal stability, were characterized. N, O-heteroatoms, aromatic motif and porous framework contained in the structure of POBI make it useful as a new type of iodine capture platform. Experimental results told that POBI can adsorb iodine in both vapor (under 75 degrees C and normal pressure) and solution (under 25 degrees C in cyclohexane) states. The maximum adsorption capacities in two states reached - 2.29 g g-1 and - 239 mg g-1, respectively. At the same time, the POBI-modified electrode (POBI/CS/GCE) illustrated stronger electrochemical response toward hazardous nitrite (NO2-) and sulfite (SO32-) anions relative to that of controlling electrodes (pristine glassy carbon electrode (GCE) and chitosan (CS)/GCE). The corresponding detection limits reached - 0.40 mu mol L-1 (NO2-) and - 16.50 mu mol L-1 (SO32-), respectively. We envisage that this work could play a positive role in further broadening the functional applications of polyisocyanide compounds.