Pyrene-BODIPY-substituted novel water-soluble cyclotriphosphazenes: synthesis, characterization, and photophysical properties.

Seda Çeti̇ndere,Adem Kiliç,Serkan Yeşi̇lot

doi:10.3906/kim-1907-40

Abstract

In the present work, pyrene-boron-dipyrromethene (BODIPY)-substituted novel water-soluble cyclotriphosphazene derivatives (6 and 7) were synthesized by click reactions between a cyclotriphosphazene derivative with a hydrophilic glycol side group (2) and BODIPYs (4 and 5). All of the new compounds (2, 6, and 7) were characterized by Fourier-transform infrared and nuclear magnetic resonance spectroscopy, as well as mass spectrometry and elemental analysis. The photophysical properties of the BODIPY-substituted cyclotriphosphazenes (6 and 7) were investigated by UV-Vis and fluorescence emission spectroscopy in water and water/solvent mixtures. It was found that the target compounds were soluble in water and could be potential candidates as water-soluble fluorescent dyes for the desired applications.

Highlights

Water-soluble fluorescent compounds are generally used to define and label targets in aqueous systems [1]
There are 2 options to overcome this problem: one is linkage of water-soluble groups to the BODIPY core [12] and the other is linkage of the BODIPY dyes to a water-soluble compound [13,14]
Hexachlorocyclotriphosphazene is a versatile starting scaffold for the synthesis of new compounds, as the chlorine groups attached to the phosphorus atoms are substituted by various nucleophiles to form reactive cyclotriphosphazenes

Summary

Introduction

Water-soluble fluorescent compounds are generally used to define and label targets in aqueous systems [1]. BODIPY dyes mainly have good solubility in organic solvents, but not in water [6]. A great deal of applications, such as fluorescence imaging and metal ion detection, are done in aqueous media and are frequently inhibited by the weak solubility of these dyes in water [7,8,9,10,11]. There has been substantial interest in cyclophosphazenes because they have an extensive stability range but they can ensure excellent photophysical properties in combination with suitable fluorescent dyes, such as BODIPYs [15,16,17,18,19] and pyrene derivatives [20,21,22]. Phosphazene compounds generally have good solubility in organic solvents. There are several examples of water-soluble phosphazenes in the literature, but to the best of our knowledge, most of them are

Objectives

Conclusion