Cd²⁺-selective fluorescence response of TQEN (N,N,N′,N′-tetrakis(2-quinolylmethyl)ethylenediamine) derivatives bearing ether oxygen-binding sites

Abstract

Moderate Zn2+ selectivity over Cd2+ (IZn/ICd = 1.6) in fluorescent enhancement of TQEN (N,N,N’,N’-tetrakis(2-quinolylmethyl)ethylenediamine) has changed to Cd2+-preference via introduction of a methoxymethyloxy (MOMO) substituent at the 8-position of one...

Effect of methoxy substituents on fluorescent Zn2+/Cd2+ selectivity of bisquinoline derivatives with a N,N′-dimethylalkanediamine skeleton

“…We previously reported several tetrakisquinoline ligands based on the TQEN (N,N,N′,N′-tetrakis(2-quinolylmethyl) ethylenediamine) 20,21 structure for fluorescent Cd 2+ detection (Chart 1). [22][23][24][25] The high coordination number and long coordination distances in the Cd 2+ complex are basic considerations for molecular design of these polyquinoline-based Cd 2+ probes. The TQEN platform is also useful for specific Zn 2+ detection [26][27][28] and in fact, quite small alterations in the molecular structure often reverse the fluorescent target metal ions between Zn 2+ and Cd 2+ .…”

A single 8‐hydroxyquinoline‐appended bile acid fluorescent probe obtained by click chemistry for solvent‐dependent and distinguishable sensing of zinc(II) and cadmium(II)

“…There have been abundant small‐molecule fluorescent probes reported for individual sensing of Zn 2+ or Cd 2+ at present [18–38]. Regretfully, these existing fluorescent molecules could only recognize one of the two metal cations.…”