A Highly Sensitive and Selective Fluorescent Sensor for Zinc(II) Ions Based on a 1,2,3‐Triazolyl‐Functionalized 2,2’‐Dipicolylamine (DPA)

Abstract

The design and synthesis of a new triazolyl‐DPA (TAZDPA) based Zn2+ fluorescent sensor is reported. The structural architect of TAZDPA contains 2,2’‐dipicolylamine (DPA) and 1,2,3‐triazolyl moiety as chelators, which synergistically coordinate with Zn2+, resulting in dramatic fluorescent emission enhancement and a notable bathochromic shift due to the inhibition of photoinduced electron transfer (PET) process. Solution state structural characterization and molecular modeling of TAZDPA suggest that N3 of 1,2,3‐triazolyl moiety and DPA coordinate with Zn2+ to afford five‐membered coordination ring. The binding behavior and stoichiometry of the TAZDPA/Zn2+complex was studied by Job's plot, which suggested 1 : 1 stoichiometry. The nature of binding behavior of TAZDPA with Zn2+ was validated by 1H‐NMR that revealed a distinct downfield shift of DPA and triazolyl protons. Under physiological condition, TAZDPA displayed high selectivity for Zn2+ over a wide range of competing common cations, exhibiting ultra‐sensitivity with a limit of detection (LOD) of 8.3×101 nM. This implies that TAZDPA can detect chronic Zn2+ concentration for freshwater (>1.84 μM) denoted by the U.S. Environmental Protection Agency (EPA).

Organic Covalent Interaction‐based Frameworks as Emerging Catalysts for Environment and Energy Applications: Current Scenario and Opportunities

“…Various anthropogenic activities are contaminating fresh water and water reservoirs. Major pollutants of the water resources include antibiotics, metal ions, [130] , [131] dyes, [132] phenolic compounds [133] and various other pollutants. [134] This makes the water inapt for humans and other aquatic life.…”

Covalent Organic Frameworks‐Based Membranes as Promising Modalities from Preparation to Separation Applications: An Overview

“…[63][64][65] Triazoles, amines and imines are the other materials which are strongly basic in nature. [66,67] Thus, purposely introducing such groups to the skeleton will help in designing CO 2 -philic materials.…”

“…It is well established that triazine based materials are strongly basic in nature with their point zero charge above the pH 7 [63–65] . Triazoles, amines and imines are the other materials which are strongly basic in nature [66,67] . Thus, purposely introducing such groups to the skeleton will help in designing CO 2 ‐philic materials.…”

Turn‐On Solid‐State Fluorescent Determination of Zinc Ion by Quinoline‐Based Covalent Organic Framework

“…Up to now, several Zn 2+ sensors based on nitrogenated heterocycles or Schiff bases have been reported. [29][30][31][32][33][34][35][36][37] Among those, quinoline moieties and its derivatives stand out, since the same moiety acts both as a metal binding site and as a fluorophore, [38] finding in many cases specific selectivity towards Zn 2+ with a "turn-on" fluorescence attributed to a chelation enhanced fluorescence (CHEF). [39] Thus, utilization of quinoline as an efficient fluorescence sensor towards metal ions has shown great promise and potential.…”