Reversing the Triazole Topology in a Cyclam‐Triazole‐Dye Ligand Gives a 10‐Fold Brighter Signal Response to Zn²⁺ in Aqueous Solution

Abstract

The fluorescence response of a set of cyclam‐triazole‐dye ligands is controlled by the appended dye, but simple reversal of the triazole topology affords a novel probe for Zn2+ with a longer fluorescence lifetime and higher fluorescence quantum yield upon Zn2+ binding (<τ> = 2.0 ns, Φf = 0.76).

Combined “dual” absorption and fluorescence smartphone spectrometers

“…5 (inset). The results are consistent with the spectral changes reported in [16]. The nonlinear fit equation derived from the data (Fig.…”

“…The pH-sensitive probe C pH used herein is a 2-butyl-6-((2-(dimethylamino)ethyl)amino)-naphthalimide fluorescent dye and the Zn 2 -responsive probe C Zn is a 6-(1,4,8,11-cyclam-1-yl)ethyl-(1,2,3-triazol-4-yl)2-ethyl naphthalimide fluoro-ionophore [16,17]. The emission bands of both probes fall within the smartphone spectral range when excited by λ abs 450 and 370 nm, respectively, and have been used in previous studies for pH measurements and Zn 2 ion detection in aqueous solutions.…”

Fluorescent measurements of Zn2+on a smartphone

“…2b. The results are consistent with the spectral changes reported in the literature [9]. The nonlinear fit equation derived from the data at λ em ~ 450 nm was used for calibration and uploaded to the smartphone app allowing for measurements of unknown concentrations within this given concentration range.…”

“…It incorporates a cyclam unit, which, in combination with the triazole moiety strongly binds to Zn 2+ , triggering the fluorescence enhancement of the appended 1,2,3-triazol-4-yl-naphthalimide fluorophore. The Zn 2+ probes' absorption is centered at λ abs = 358 nm and the emission is centered at λ abs = 458 nm [9]. Upon coordination to Zn 2+ the emission shows a 6-fold fluorescence enhancement in water.…”

“…The Zn 2+ -responsive probe used herein is the readily synthesized 6-(1,4,8,11-cyclam-1-yl)ethyl-1,2,3-triazol-4-yl)2-ethyl-napthalimide fluoro-ionophore [9]. The molecular structure of the ligand with and without Zn 2+ coordination is shown in Fig.…”