Salicylaldimine‐functionalized poly(m‐phenyleneethynylene) as turn‐on chemosensor for ferric ion

Abstract

A new turn on fluorescent probe for ferric ion based on poly(m-phenyleneethynylene salicylaldimine) (PPE-IM) has been developed. The preparation of PPE-IM involves postpolymerization functionalization of the corresponding polymeric amine, PPE-AM, via the condensation with salicylaldehyde. The degree of polymerization of both PPE-IM and PPE-IM is 17 with polydispersity index of 1.5. In aqueous solution, the polymeric PPE-IM is highly stable unlike its small molecule analog which is gradually hydrolyzed. The weak fluorescence of initial PPE-IM (k em 5 470) is greatly enhanced by 300 folds upon the addition of Fe 31 . The 1 H NMR reveals that the fluorescence enhancement is caused by Fe 31 -induced hydrolysis of the imine group. The sensing system shows a detection limit of 0.14 lM of Fe 31 .

A Non‐Hydrolysis Reaction‐Based Imine for Fluorescence Response toward Al3+ Ions with Extremely High Selectivity

“…(ii) increasing the hydrophobicity is helpful for protecting the imine bond, able to improve selectivity in fluorescence response. Such contribution of hydrophobicity driven aggregation to protect imine bond was also observed in previously reported polymer and monomer imines cases [15] …”

“…Such contribution of hydrophobicity driven aggregation to protect imine bond was also observed in previously reported polymer and monomer imines cases. [15] Furthermore, probe 4 was obtained from a condensation reaction between 2-NA and 4-hydroxyphenylaldehyde to check whether the À OH group on ortho-position of phenylaldehyde has an effect on the hydrolysis reaction and on the selectivity of fluorescence response. The instability of probe 4 could also be concluded from the incubation time-dependent fluorescence spectral change in methanol solution (Figure 3d).…”

“…Therefore, how to develop imines to overcome this shortcoming, that is, transition metal ions are easy to promote the occurrence of hydrolysis reactions of imines, is an interesting and novel topic for constructing fluorescence sensing systems. We should note that, besides salen-based imines, [13,14] N-substituted imine derivatives including hydrazones and oximes, [3] and imine-based polymers [15] have been shown to be water-compatible and even serve as excellent chelators for metal ions to develop a variety of architectures or non-hydrolysis based fluorescence probes, in particular sensing Zn 2 + , Hg 2 + , Al 3 + , and Fe 3 + ions. However, systematically studying the stability of imines and further developing coordination-based fluorescence probes remain limited cases.…”

A Novel Conjugated Polymer Consists of Benzimidazole and Benzothiadiazole: Synthesis, Photophysics Properties, and Sensing Properties for Pd2+

“…In the past decades, fluorescence chemosensors based on conjugated polymers (CPs) as sensing materials have rapidly developed in energy, chemical engineering, environmental protection, biochemistry and medical treatment fields with their outstanding properties . These materials have received intensive attention because of their favorable selective and sensitive ability, environment‐friendly biocompatibility, and fluorescence amplification effect.…”

“…In the past decades, fluorescence chemosensors based on conjugated polymers (CPs) as sensing materials have rapidly developed in energy, chemical engineering, environmental protection, biochemistry and medical treatment fields with their outstanding properties. [1][2][3][4] These materials have received intensive attention because of their favorable selective and sensitive ability, environment-friendly biocompatibility, and fluorescence amplification effect. Compared with a small organic compound fluorescence probe, the delocalized π-electronic conjugated "molecular wires" effect can help CPs display unique signal amplification effect by the facile energy migration along the polymer backbone upon light excitation.…”