Reaction-Based Sensing of Fluoride Ions Using Built-In Triggers for Intramolecular Charge Transfer and Photoinduced Electron Transfer

Abstract

Two Bodipy derivatives with silyl-protected phenolic functionalities signal fluoride concentrations both in solution and in a poly(methyl methacrylate) matrix. The exact location of the "nascent" phenolate group is important. If it is at the meso position, photoinduced electron transfer is triggered; however, if it is in full conjugation via a styryl moiety to the Bodipy core, strong intramolecular charge transfer is triggered, resulting in a large red shift in the absorbance peak. In either case, a selective methodology for fluoride sensing is the invariable result.Anion sensing is a challenging task. 1 This is due to large variations in size, shape, charge distribution, and strong solvation in polar and/or H-bond donor solvents. While continuous monitoring and real time imaging of anionic species require reversible chemosensors, for some anions, a reaction-based sensor, 2 a "chemical dosimeter". would be equally useful. For practical applications, one can easily envision a "dipstick" for selected anions such as cyanide or fluoride considering how and where it could be relevant to measure the concentrations of these ions. Fluoride, being a strong base in organic solvents can be considered to be an easy target for sensing, 3 as many different types of fluores- †

Quantitative Structure‐Fluorescence Property Relationship Analysis of a Large BODIPY Library

“…[60] ICT has been discussed with BODIPY-linked phenol and anisole, as well, where the oxygen is the electron donating group. [61,[64][65][66] However, the emission maximum of these compounds was found to be solvent independent. Fluorescence emission intensities decreased with increasing pH suggesting a non-emissive excited state of the phenoxide anion due to very efficient ICT.…”

A Bodipy-Phenol-Based Sensor for Selectively Recognizing Three Basic Anions

“…Similar changes was also observed upon the stepwise addition of AcO -and H 2 PO 4 -( Figure S6 and S7), respectively. Such quenching can be attributable to the occurrence of ICT quenching the exited state of BODIPY moiety by the phenolate salt 22 . It was found that 1 demonstrated fluorescence quench in varying degrees, which was 97-fold for F -, 10-fold for AcO -and 5-fold for H 2 PO 4 -in Figure 7.…”

“…Where 3 shows the special selectivity for F -through color change and fluorescence quenching, the hindrance of tert-butyl groups and the fitness of Brønsted acid-base are responsible for selective F -recognition over other tested anions. To our knowledge, both PET and ICT processes could lead to different optical output 22,23 . We therefore wonder if phenol unit can be introduced at C(3)-position of BODPIY by a vinyl spacer to acquire an ICT-based anion sensor.…”

Development of a DNA sensor using a molecular logic gate

“…Remarkable progress has been made since then in the development of molecular logic gates [2][3][4][5][6][7][8][9][10][11][12][13][14]. The change in fluorescence characteristics of a dye due to the introduction of some external agent can be considered to be analogous to the digital responses in electronic logic gates.…”

“…Basic logic operation of a molecular logic gate is the same as that of the electronic one, the only difference is in the input and output signal. Nowadays, these molecular logic gates can be used as simple as well as more complex devices [17][18][19] such as adders and subtractors [2][3][4], multiplexers/demultiplexers [5][6][7], encoders/decoders [8,9], keypad locks [10][11][12][13][14] etc. Among many applications of molecular logic gates, one of the most interesting is the investigation of the inside components of a cell, where silicon-based analogues are not expected to reach [2].…”