Zinc(II) bis(dipyrromethenate)s-based «Оn–Off» fluorescent sensors for xylenes

• Published in: Journal of luminescence Vol. 192; pp. 1203 - 1210
• Main Authors: Ksenofontov, A.A., Guseva, G.B., Antina, E.V., Nuraneeva, E.N.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2017
• Subjects: Aromaticity, Fluorescence quenching, Detection limit; Sensor; Zinc(II) bis(dipyrromethenate), Xylene; Zinc(II) bis(dipyrromethenate), Xylene; Aromaticity, Fluorescence quenching, Detection limit; Sensor
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2017.08.058

This paper presents the results of spectral-luminescence research of binuclear zinc(II) helicates with deca-, octa-, and tetramethylsubstituted 3,3′-bis(dipyrromethene)s ([Zn2L2]) in binary mixtures of cyclohexane with m-, o- and p-xylene. Structure effects of [Zn2L2], and aromaticity criteria of analytes (HOMA, NICS, μ) on the fluorescence quenching efficiency of [Zn2L2] in the presence of xylenes was considered. It was found that decamethyl substituted 3,3′-bis(dipyrromethenate)s compared to octa-, and tetramethylsubstituted-analogs shows the highest fluorescence sensitivity to the presence of aromatic compounds. Quantum-chemical modeling showed that [Zn2L2] fluorescence quenching in the xylenes presence is caused by the formation of [Zn2L2An] (n = 1 or 2) supramolecular structures. High specificity of spectral-luminescent characteristics changing in the presence of xylenes provides the possibility of using [Zn2L2] helicates as new fluorescent sensors for trace amounts (6.5–99ppm) detection of methylbenzenes in organic media.
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•The [Zn2L2] fluorescence quenching in the xylenes (A) presence due to the formation of [Zn2L2An].•The supramolecular complexes of [Zn2L2An] are formed by π–stacking.•The [Zn2L2] fluorescence efficiency increases with increasing xylenes aromaticity.•Helicates exhibit good selectivity to xylenes with detection limit is 6.5–99ppm.•Zinc(II) bis(dipyrromethenate)s are recommended as a fluorescent sensors of xylenes.