Dual‑mode colorimetric/fuorescent chemosensor for Cu2+/Zn2+ and fngerprint imaging based on rhodamine ethylenediamine bis(triazolyl silsesquioxane)

Abstract

A novel dual functional and visual rhodamine ethylenediamine bis(triazolyl silsesquioxane) (RBS) chemosensor was successfully synthesized using “click” chemistry. The results have unambiguously demonstrated that RBS can act in fuorescent and colorimetric sensing of Cu2+ and Zn2+ by their respective coordination with triazole structures and, more importantly, it has also been found that triazole-amide of RBS could turn on chelation-enhanced fuorescence (CHEF) of Cu2+. Remarkably, the addition of Cu2+ triggered an enhanced fuorescent emission by 63.3-fold (ϕF=0.41), while Zn2+ enhanced it 48.3-fold (ϕF=0.29) relative to the original RBS (ϕF=0.006) in acetonitrile (MeCN) solvent. The fuorescent limit of detection for Cu2+ and Zn2+ is similar and fall within 3.0 nM, while under colorimetric sensing the responses were 2.14× 10–8 and 4.0× 10–8 mol L−1, respectively. Moreover, the efective sensing profle of RBS and extended applications of RBS–Cu2+ and RBS–Zn2+ for fngerprinting detection and imaging were observed with adequate sensitivity, stability and legibility under the dual visual responses.