Effect of Cyano and Tetrazole Side Groups on the Photophysical and Chelating Properties of Anthracene‐Based Polymers

Abstract

This paper covers the conception of new soluble and filmogene conjugated polymers (PAnSCN and PAnSCN‐Tet) for heavy metal sensing application. The prepared materials are based on the highly emissive anthracene chromophore and contain tetrazole and/or cyanide groups in their molecular chain backbones. The effect of the electron withdrawing groups on photophysical properties and the chelating abilities of the elaborated organic materials were investigated. The optical analysis shows that the CN groups reduced slightly the optical band‐gap of the polymer, however the steric hindrance of tetrazole units dominates their electronic effects leading to a blue‐shift of its absorption spectrum. Also, the electrochemical study reveals a considerable electronic affinity increase by 0.84 eV when passing from PAnSCN into PAnSCN‐Tet. DFT calculations has been employed to estimate the optimized macromolecular structure of both polymers and a notable change in geometry in terms of planarity was observed depending on the incorporated withdrawing group. The synthesized polymers were studied as optical sensors. The changes in the photoluminescence intensity were used to evaluate the binding affinity of the two materials to different metal ions. The obtained results showed considerable decrease in photoluminescence (quenching) responses with Mn2+ cations a short time after adding the cations to both polymer solutions with better sensitivity and selectivity in the case of the PAnSCN‐Tet.