Fluoride Anion Research Articles

Quantitative Studies on the Structure of Zirconium Fluoride Anions in Molten LiF and FLiBe

AbstractThe quantitative distribution of different zirconium fluoride anions in molten LiF and FLiBe mixtures has been investigated by Raman and theoretical calculations. In molten LiF, zirconium fluorides are present in the forms of ZrF62− and ZrF73−. After correction, the Raman scattering cross sections corresponding to the symmetric stretching vibrational bands were obtained. The ZrF73− anion was a dominant species whatever the concentration of ZrF4 between 5 and 30 mol % in LiF melt, even though the content of which presents a decreasing trend from 92.3 to 73.2 mol % with the increase of ZrF4. Similar specification was identified in FLiBe‐ZrF4, and ZrF62−/ZrF73− anions were found in equilibrium with free F− ions and beryllium fluoride anions. Detailed deconvolution and calculation were performed on the Raman spectrum measured in the FLiBe melt containing 10 mol % ZrF4 giving a quantitative content of ZrF73− 78.1 mol % and ZrF62− 21.9 mol %.

Surprising Complexity of the [Gd(AAZTA)(H2O)2]- Chelate Revealed by NMR in the Frequency and Time Domains.

Typically, Ln(III) complexes are isostructural along the series, which enables studying one particular metal chelate to derive the structural features of the others. This is not the case for [Ln(AAZTA)(H2O)x]− (x = 1, 2) systems, where structural variations along the series cause changes in the hydration number of the different metal complexes, and in particular the loss of one of the two metal-coordinated water molecules between Ho and Er. Herein, we present a 1H field-cycling relaxometry and 17O NMR study that enables accessing the different exchange dynamics processes involving the two water molecules bound to the metal center in the [Gd(AAZTA)(H2O)2]− complex. The resulting picture shows one Gd-bound water molecule with an exchange rate ∼6 times faster than that of the other, due to a longer metal–water distance, in accordance with density functional theory (DFT) calculations. The substitution of the more labile water molecule with a fluoride anion in a diamagnetic-isostructural analogue of the Gd-complex, [Y(AAZTA)(H2O)2]−, allows us to follow the chemical exchange process by high-resolution NMR and to describe its thermodynamic behavior. Taken together, the variety of tools offered by NMR (including high-resolution 1H, 19F NMR as a function of temperature, 1H longitudinal relaxation rates vs B0, and 17O transverse relaxation rates vs T) provides a complete description of the structure and exchange dynamics of these Ln-complexes along the series.

Accelerating the Convergence of Self-Consistent Field Calculations Using the Many-Body Expansion.

The balance between cost-effective and sufficiently accurate methods represents the proverbial "promised land" for quantum chemistry calculations. The burden thus falls upon theoretical and computational chemists to provide such alternatives to mitigate the issues that arise from the employ of finite computing resources. In this paper, we attempt to demonstrate the importance of the quality of the initial guess for the self-consistent field (SCF) calculation when considering cost reduction techniques. We broach this challenge by using the many body expansion (MBE) to yield high quality density matrices (DMs) which, in turn, are applied as an SCF initial guess. The MBE-DM approaches combined with purification schemes and distance-based cutoff schemes can serve as initial guesses to reduce the SCF cycles necessary for convergence or derive energy directly through one Fock build. To this end, four unique types of clusters including water clusters, fluoride anion water clusters, sodium cation water clusters, and ammonium-bisulfate salt clusters have been used to test the performance of MBE-DM where its truncation at three-body expansion, MBE(3)-DM, shows vast improvement for those four clusters with reductions in the number of SCF cycles up to 40% as compared with the traditional superposition of atomic densities (SAD) guess. Other types of typical initial guesses, superposition of atomic potentials (SAP) and basis set projection (BSP), perform much worse than MBE-DM and SAD. In addition, the MBE-DM shows consistency across an array of fragment types irrespective of charges, size, level of theory, and basis set selection. Through MBE(3)-DM with the distance cutoff and the average purification scheme, the energy can be obtained directly with a mere 3.2 mH of the mean absolute deviation (MAD) for (H2O)N=6-55 which is at least 73 times better than the energy prediction using the typical initial guesses (SAD, SAP, and BSP). The corresponding MAD per monomer is only 0.14 mH which reaches the threshold of the "dynamical accuracy". The promising results of the methods outlined in this paper not only indicate two direct routes for computational cost reduction but also lay the possible foundation for composite techniques (i.e., ab initio sampling) that make best use of near converged values as their starting point.

Fabrication of In(III)-alizarin red S complex trap for efficient detection of fluoride ion in aqueous environs

The work discusses about the synthesis of indium-alizarin red S complex followed by its application toward the sensing of F¯ ion. At first, the interaction between indium and alizarin red S dye was studied at three different pH medium, pH 4, 7 and 9, of which pH 7 gave the best result. The indium-alizarin red S complex so obtained was then utilized for the ratiometric sensing of fluoride ion using absorption spectroscopy with variation of temperature. The lowest limit of detection (0.040 mM) was obtained at 313 K. The mechanism for the sensing of F¯ ion was then investigated using isothermal titration calorimetry. The endothermic nature of the interaction between F¯ ion with indium-alizarin red S complex shows temperature dependence on the sensing experiment. At the end, the utility of the technique toward natural sample was also examined. The present work reports a simple, rapid and efficient detection of fluoride anion in environmental water samples.

Sorting Phenomena and Chirality Transfer in Fluoride-Bridged Macrocyclic Rare Earth Complexes.

The reaction of fluoride anions with mononuclear lanthanide(III) and yttrium(III) hexaaza-macrocyclic complexes results in the formation of dinuclear fluoride-bridged complexes. As indicated by X-ray crystal structures, in these complexes two metal ions bound by the macrocycles are linked by two or three bridging fluoride anions, depending on the type of the macrocycle. In the case of the chiral hexaaza-macrocycle L1 derived from trans-1,2-diaminocyclohexane, the formation of these μ2-fluorido dinuclear complexes is accompanied by enantiomeric self-recognition of macrocyclic units. In contrast, this kind of recognition is not observed in the case of complexes of the chiral macrocycle L2 derived from 1,2-diphenylethylenediamine. The reaction of fluoride with a mixture of mononuclear complexes of L1 and L2, containing two different Ln(III) ions, results in narcissistic sorting of macrocyclic units. Conversely, a similar reaction involving mononuclear complexes of L1 and complexes of achiral macrocycle L3 based on ethylenediamine results in sociable sorting of macrocyclic units and preferable formation of heterodinuclear complexes. In addition, formation of these heterodinuclear complexes is accompanied by chirality transfer from the chiral macrocycle L1 to the achiral macrocycle L3 as indicated by CPL and CD spectra.

Cooperative Asymmetric Cation-Binding Catalysis.

Asymmetric cation-binding catalysis in principle enables the use of (alkali) metal salts, otherwise insoluble in organic solvents, as reagents and effectors in enantioselective reactions. However, this concept has been a formidable challenge due to the difficulties associated with creating a highly organized chiral environment for cations and anions simultaneously. Over the last four decades, various chiral crown ethers have been developed as cation-binding phase-transfer catalysts and examined in asymmetric catalysis. However, the limited ability of chiral crown ethers to generate soluble reactive anions in a confined chiral cage offers a restricted reaction scope and unsatisfactory chirality induction. To address the constraints of monofunctional chiral crown ethers as cation-binding catalysts, it is therefore desirable to develop a cooperative cation-binding catalyst possessing secondary binding sites for anions, which enables the generation of a reactive anion within a chiral cage of a catalyst. This account summarizes our design, development, and applications of chiral BINOL-based oligoethylene glycols (oligoEGs) as a new type of bifunctional cation-binding catalyst. We initially found that achiral oligoEGs were efficient promoters in nucleophilic fluorination with potassium fluoride. Thereby, we hypothesized that, by breaking the closed cyclic ether unit of chiral crown ethers, the free terminal -OH groups could activate the electrophiles by hydrogen bonding whereas the ether oxygens could act as the Lewis base to coordinate metal ions, thus generating soluble anions in a confined chiral cage. This hypothesis was realized by synthesizing a series of chiral variants of oligoEGs by connecting two 3,3'-disubstituted-BINOL units with glycol linkers. Readily available BINOL-based chiral oligoEGs enabled numerous asymmetric transformations out of the reach of chiral monofunctional crown ether catalysts. We have demonstrated that this new type of bifunctional cation-binding catalysts can generate a soluble fluoride anion from alkali metal fluorides, which can be a versatile chiral promoter for diverse asymmetric catalytic reactions, kinetic resolution (selectivity factor of up to ∼2300), asymmetric protonation, Mannich reactions, tandem cyclization reactions, and the isomerization of allylic alcohols and hemithioacetals. We have also successfully utilized our chiral oligoEG catalysts along with alkali metal salts of carbon- and heteroatom-based nucleophiles, respectively, for asymmetric Strecker reactions and the asymmetric synthesis of chiral aminals. The power of our cooperative cation-binding catalysis was exemplified by kinetic resolution reactions of secondary alcohols, achieving highly enantioselective catalysis with only <1 ppm loading of an organocatalyst with high TOFs (up to ∼1300 h-1 at 1 ppm catalyst loading). The broadness and generality of our cooperative asymmetric cation-binding catalysis can be ascribed, in a similar fashion, to active-site architectures of enzymes using allosteric interactions, highly confined chiral cages formed by the incorporation of alkali metal salts in the catalyst polyether chain backbone, and the cooperative activation of reacting partners by hydrogen-bonding and ion-ion interactions. Confining reactive components in such a chiral binding pocket leads to enhanced reactivity and efficient transfer of the stereochemical information.

Synthesis of Boratrane-pendant Random Copolymers by Side-chain Modification

Random copolymers bearing triethanolamine borate (TEAB) groups in the side chains were investigated as the first example of boratrane-containing polymers. The title polymers were synthesized via two steps of polymer reactions from random copolymers of styrene and glycidyl methacrylate. The obtained polymers exhibited superior thermal properties compared to the precursor polymers owing to the rigid cage structures of TEAB. The pendant TEAB groups were relatively stable to hydrolysis, but were quantitatively hydrolyzed in the presence of fluoride anions.

Nonlinear optical properties of a new polar bismuth tellurium oxide fluoride, Bi3F(TeO3)(TeO2F2)3

A novel noncentrosymmetric polar bismuth tellurium oxide fluoride, Bi3F(TeO3)(TeO2F2)3, has been hydrothermally synthesized by using Bi2O3, TeO2, and HF solution at 230 °C. The structural backbone of Bi3F(TeO3)(TeO2F2)3 is composed of several polyhedra with lone pair cations, such as BiO6F3, TeO2F2, and TeO3. The asymmetric geometric features found from the polyhedra of Bi3+ and Te4+ should be attributed to the lone pairs on the cations. The overall framework of Bi3F(TeO3)(TeO2F2)3 can be considered as a three-dimensional hexagonal tungsten oxide-like topology. The UV–vis diffuse reflectance spectral data suggest that the title compound has a wide band gap of ca. 3.85 eV due to the distortions of the asymmetric units, as well as the electronegative fluoride anions. Second-harmonic generation (SHG) measurements using a 1064 nm radiation indicate that Bi3F(TeO3)(TeO2F2)3 reveals a nonphase-matching behavior and ca. 9 times larger SHG counts than that of α-SiO2. The near-static value of the second-order nonlinear optical susceptibility, χS(2), of the reported compound is calculated to be ca. 5.1 ± 0.6 pm/V. The wavelength-dependent SHG measurements indicate that the SHG counts of Bi3F(TeO3)(TeO2F2)3 decrease as the excitation wavelength increases from 1064 to 1600 nm.

Effects of anatase TiO2 morphology and surface fluorination on environmentally relevant photocatalytic reduction and oxidation reactions

Aiming at clarifying the interplay on TiO2 photoactivity between particle morphology and surface fluorination, the photocatalytic performance of anatase nanocrystals, characterized by a pseudo-spherical shape or a nanosheet structure, is investigated in both a reduction and an oxidation reaction, either in the absence or in the presence of added fluoride anions. Cr(VI) photocatalytic reduction is strongly favored by a large exposure of anatase {001} facets; however, surface fluorination leads in this case to a morphology-independent photoactivity decrease, due to the decreased adsorption of the reaction substrate. More interestingly, a beneficial synergistic effect between the platelet-like anatase morphology and TiO2 surface fluorination is clearly outlined in Rhodamine B photocatalytic degradation, possibly resulting from the intrinsic ability of fluorinated {001} anatase facets of boosting •OH radical mediated oxidation paths, due to their larger amount of surface –OH groups, as revealed using Fourier-transform infrared spectroscopy.

The effect of layered double hydroxide on fluoride release and recharge from a commercial and an experimental resin varnish

ObjectivesLayered Double Hydroxide (LDH) is capable of fluoride anion exchange and release. This study investigated the effects of incorporating ZnAl-LDH in commercial and experimental dental varnishes, on fluoride release and re-release after charging in NaF. MethodsFive discs of each material (commercial ClinproXT varnish and experimental light cured resin varnish), with and without 9%ZnAl-LDH were immersed and agitated in deionised water (DW) at 37 °C. A fluoride ion selective electrode measured fluoride release in DW daily over two-weeks. At 3, 6, 9 and 12 days the discs were recharged in 15 ml 0.05 M NaF solution (37 °C) for five minutes followed by immersion in DW. Energy dispersive X-ray spectra (EDS), weight changes and SEMs were performed on discs, before and after each cycle. ResultsEvidence of ZnAl-LDH was confirmed by the presence of peaks for zinc and aluminium in EDS spectra. Cumulative fluoride and mean fluoride released between Clinpro, Clinpro + LDH and resin were significantly different (ANOVA, Tukey’s HSD post-hoc test, p < 0.001) except between the resin and resin + LDH. Mean fluoride concentrations differed significantly after every recharge between Clinpro, Clinpro + LDH and resin, but not between the resin and resin + LDH (p < 0.01). The weights and SEMs of the experimental resins +/-LDH, appeared to be stable whilst the weights of Clinpro samples +/−LDH, fluctuated and fragmented. SignificanceClinproXT and experimental resin containing ZnAl-LDH recharged with fluoride did not significantly increase fluoride release compared to the unmodified materials. However, all LDH-F incorporated materials demonstrated fluoride recharging properties which appear beneficial to dentistry and thus further work is required to improve these properties.

Matrix-assisted production of actinide molecular anions for AMS

The multiple probable oxidation states of actinide elements can lead to their molecular anions to result in complicated yield patterns from a Cs+ sputter ion source. For actinides AMS, two methods can be practiced in order to concentrate the yields into just one or two anion species. The present common practice has been to avoid excessive oxygen reactions in the sputter targets, so that the mono-oxide anions can be produced with good or applicable ionization efficiencies. However, this method requires the typical 860-type Cs+ sputter ion sources to be operated with relatively high Cs+ fluxes, a condition that not all such sources in use can be operated with lasting stability. On the contrary, with low Cs+ fluxes, good or applicable ionization efficiencies can also be achieved for producing element-specific polyatomic oxide, oxyfluoride, or fluoride anions of actinides, if the sputter targets are aided with dominantly oxidizing or fluorinating matrices. This paper describes a systematic study of such phenomena using ZnO and FeF3 to form the respective oxidizing and fluorinating matrices. It was found that using the chosen set of polyatomic fluoride anions and the FeOxHy + FeF3 sputter targets, not only all rare actinides could be measured with low backgrounds matching those using mono-oxides, but also with the available ionization efficiencies fully utilized within a shorter time. A few additional merits are also noted.

Highly sensitive and cost-effective fluorescent turn-on sensors based on octamethylcalix[4]pyrrole receptor for the detection of fluoride anion

Cost-effective fluorescence turn-on indicator-displacement-assay (IDA) sensors based on octamethylcalix[4]pyrrole receptor and tetrabutylammonium salts of 4-methylumbelliferone and fluorescein indicators were developed for highly sensitive detection of fluoride anion. The IDA sensor assembly relies on the hydrogen bonding between calix[4]pyrrole and carboxylate units of indicators and further displacement replacement of receptors with target analyte. While all the sensors displayed rapid and selective sensitivity towards fluoride over the other anions, 4-methylumbelliferone based IDA system was also found to have a visual color change for the sensing of fluoride anion. The experimental results revealed that fluorescein-based IDA sensor could be used for the sensing of fluoride anion with a detection limit as low as 3.2 nM.

Incorporation of Ions into Nanostructured Anodic Oxides-Mechanism and Functionalities.

Anodic oxidation of metals leads to the formation of ordered nanoporous or nanotubular oxide layers that contribute to numerous existing and emerging applications. However, there are still numerous fundamental aspects of anodizing that have to be well understood and require deeper understanding. Anodization of metals is accompanied by the inevitable phenomenon of anion incorporation, which is discussed in detail in this review. Additionally, the influence of anion incorporation into anodic alumina and its impact on various properties is elaborated. The literature reports on the impact of the incorporated electrolyte anions on photoluminescence, galvanoluminescence and refractive index of anodic alumina are analyzed. Additionally, the influence of the type and amount of the incorporated anions on the chemical properties of anodic alumina, based on the literature data, was also shown to be important. The role of fluoride anions in d-electronic metal anodizing is shown to be important in the formation of nanostructured morphology. Additionally, the impact of incorporated anionic species, such as ruthenites, and their influence on anodic oxides formation, such as titania, reveals how the phenomenon of anion incorporation can be beneficial.

Straightforward Access to High-Performance Organometallic Catalysts by Fluoride Activation: Proof of Principle on Asymmetric Cyanation, Asymmetric Michael Addition, CO2 Addition to Epoxide, and Reductive Alkylation of Amines by Tetrahydrofuran

We demonstrate that well-known transition metal catalysts can be transformed into high-performance versions by the simple use of a fluoride anion source. In situ fluoride-activated catalysts are hi...

DFT/TD-DFT study to decipher the fluoride induced ring opening process of spiropyran

DFT/TD-DFT methods were used to determine the fluoride anion sensing mechanism of 3′,6′-Bis(tert-butyldimethylsilyloxy)spiro[benzo[f]chromene3,9′ffuorene], abbreviated as SP. The description of ring opening in the ground state of SP molecule and its isomerization in open form is presented. It was revealed from the study that in the ground state, SP is the most stable form in contrast with the isomer obtained in the open form. To initiate the ring opening, at first, the fluoride ion attacks as a nucleophile to de-silylate the SP molecule. This attack of fluoride ion may induce Cspiro-O bond cleavage leading to the formation of two anionic species, i.e., MC-D1 and MC-D2 respectively (MC is merocyanin). The mono-de-silylation process was endogenic, which was followed by the ring opening process. Furthermore, the orthogonal geometry of probe SP does not show ICT character, whereas, MC-D1 and MC-D2 displayed ICT character owing to the formation of planar geometry along with an increase in conjugation. The fluorescence property of SP, and most stable isomers of open form (CT, MC-D1, and MC-D2) were predicted theoretically. The calculated emission spectra uncovered that SP may show fluorescence, which could be quenched in presence of fluoride anion.

A Multiple Excited-State Engineering of Boron-Functionalized Diazapentacene Via a Tuning of the Molecular Orbital Coupling.

Harvesting high-energy excited-state energy is still challenging in organic chromophores. An introduction of boron atoms along the short axis of the diazapentacene backbone induces multiple emission characteristics. Our studies reveal that the weak molecular orbital (MO) coupling of the S3-S1 transition is responsible for the slow internal conversion rates. Such MO coupling-regulated anti-Kasha emission is different from the large band gap-induced anti-Kasha emission character of classical azulene derivatives. Theoretical studies reveal that a strong MO coupling of the S3-S0 transition is responsible for the higher photoluminescence quantum yield of the anti-Kasha emission in a more polar solution (tetrahydrofuran: 11%; cyclohexane: 0%). Such an MO coupling factor is generally overlooked in anti-Kasha emitters reported previously. Furthermore, the multiple emission can be regulated by solvent polarity, solvent temperature, and fluoride anion binding. As a proof of concept of harvesting high-energy emission, the multiple emission character has allowed us to design single-molecule white-light-emitting materials.

Synthesis of pyrrolyl-BODIPY dyes through regioselective SN Ar reactions and application as a fluorescent sensor for fluoride anion

Two pyrrolyl-BODIPY dyes with 3,5-di-[Formula: see text]-butyl-4-hydroxyphenyl group were synthesized through stepwise S[Formula: see text]Ar reactions of 3,5-dibromoBODIPYs, which were used as a fluorescent sensor for basic anions. The intermediate pyrrolyl-BODIPYs 2a–2b were regioselectively synthesized through an efficient S[Formula: see text]Ar reaction between 3,5-dibromoBODIPY 1a and pyrroles. The target pyrrolyl-BODIPYs 3a–3b with a 3,5-di-[Formula: see text]-butyl-4-hydroxyphenyl group at 3-position and a pyrrole substituent at 5-position were obtained through a second S[Formula: see text]Ar reaction between pyrrolyl-BODIPYs 2a–2b and high steric hindrance 2,6-dibutylphenol in 90% and 88% yields, respectively. In contrast, the reaction between pyrrolyl-BODIPYs 2a–2b and phenol gave pyrrolyl-BODIPYs 3c–3d with phenoxy substituent at 3-position. These pyrrolyl-BODIPYs 3a–2d show strong, sharp absorptions (551–604 nm) and emissions (564–634 nm) with high fluorescence quantum yields up to 0.86 in dichloromethane. Importantly, the 3,5-di-[Formula: see text]-butyl-4-hydroxyphenyl group of pyrrolyl-BODIPY 3a showed a turn-off fluorescent response toward fluoride anion.

Chromogenic detection of fluoride, dihydrogen phosphate, and arsenite anions based on 2,4-dinitrophenyl hydrazine receptors: spectral and electrochemical study

ABSTRACT The colorimetric recognition of biologically relevant fluoride (F−), acetate (AcO−), and dihydrogen phosphate (H2PO4 −) ions, and poisonous arsenite (AsO2 −) ions, was devised and new receptors for these anions synthesised via the Schiff base condensation procedure. UV–visible titration, fluorescence titration, 1H-NMR titration, and cyclic voltammetry were used to explore the interactions of receptors R1–R3 with anions and possible detection mechanisms. The synthesised probes could sense inorganic fluoride, acetate, dihydrogen phosphate, and arsenite in the organo–aqueous medium (H2O/ Dimethylsulphoxide, 1: 9, v/v) and displayed a change in colour detectable to the naked eye. Out of the three synthesised receptors, receptor R1 showed better sensing ability of fluoride, acetate, dihydrogen phosphate, and arsenite ions in the organo–aqueous medium with a lower detection limit of 0.1 ppm, 0.171 ppm, 0.194 ppm, and 0.144 ppm, respectively. All three receptors formed complexes with the anions through H-bonding interaction followed by deprotonation of the NH proton.

DFT and TD-DFT Study of Only First Diaminomalenonitrile Based Molecular Receptor for Fluoride Anion: Correlation of Calculated and Experimental Results

In this work, the sensing mechanism of a novel anion receptor, 2-amino-((E)-(4-cyanobenzalidine) amino) maleonitrile reported by Sankar et al. (Analyst 138:4760-4763, 2013) was investigated theoretically with the help of density functional theory (DFT) and time-dependent density functional theory (TD-DFT). From the frontier molecular orbital analysis, it is reasonable to support the proposed charge transfer (ICT) enhancement in the receptor molecule in the presence of F−. A significant reduction in the energy gap (ΔE) from 4.014 eV to 2.342eV between highest occupied and lowest unoccupied energy levels was revealed, leading to the strong redshift of its absorption characteristics. Moreover, 1H NMR was also calculated to further understand the mechanistic insights by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G (d,p) basis set. The spectra were simulated, and the chemical shifts linked to TMS were compared with experimental. Besides, Intrinsic Reaction Coordinates (IRC) were also calculated to understand the sensing mechanism.

Efficient Colorimetric Fluoride Anion Sensor Based on π-Conjugated Carbazole Small Molecule.

The ability to detect fluoride anions with high selectivity and sensitivity by using the naked eye is crucial yet challenging. In this study, a novel, simple conjugated organic dye, N-tert-butyldimethylsilyl-3,6-diiodocarbazole (CA-TBMDS) was developed and used for the first time as a colorimetric sensor for fluoride. CA-TBMDS was found to be a highly sensitive fluoride chemosensor, with a detection limit as low as 3 × 10−5 M. The reaction of CA-TBMDS with fluoride anions in a tetrahydrofuran solution resulted in a color change from colorless to yellow under ambient light, which can be discriminated by the naked eye. The sensor operated via intermolecular proton transfer between the amide units and the fluoride anion, as confirmed by proton nuclear magnetic resonance titration. CA-TBMDS is not only highly sensitive to fluoride anions, but also exhibits high sensitivity in the presence of various ions. This work demonstrates that N-butyldimethylchlorosilane-based organic dyes have prospective utility as a type of fluoride anion chemosensor.