- A water-soluble fluorescent fluoride ion probe based on Alizarin Red S-Al(III) complex
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A new water-soluble fluorescent fluoride ion signaling system has been developed based on the ligand exchange mechanism in aqueous medium. This procedure is based on the exchange of two Alizarin Red S (ARS) molecules coordinated to Al(III) by fluoride ion without interference from other common anions. The binary complex of ARS with Al(III) provides a sensitive signaling system for fluoride ion in the concentration range from 5 × 10-6 to 3 × 10-4 M. The ligand exchange reaction of ARS-Al(III) complex with fluoride ion has been investigated by UV-vis and fluorescence spectroscopies combined with the AM1 semi-empirical quantum chemical calculations. The pale orange fluorescence (λmax = 575 nm) exhibited by the complex upon excitation at 435 nm decreases in intensity with fluoride addition with a detection limit of 0.1 mg L-1.
- Sai Sathish,Ravi Kumar,Nageswara Rao,Anil Kumar,Janardhana
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- Quantum-chemical calculations and IR spectra of the (F2)MF 2 molecules (M = B, Al, Ga, In, Tl) in solid matrices: A new class of very high electron affinity neutral molecules
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Electron-deficient group 13 metals react with F2 to give the compounds MF2 (M = B, Al, Ga, In, Tl), which combine with F 2 to form a new class of very high electron affinity neutral molecules, (F2)MF2, in solid argon and neon. These (F 2)MF2 fluorine metal difluoride molecules were identified through matrix IR spectra containing new antisymmetric and symmetric M-F stretching modes. The assignments were confirmed through close comparisons with frequency calculations using DFT methods, which were calibrated against the MF3 molecules observed in all of the spectra. Electron affinities calculated at the CCSD(T) level fall between 7.0 and 7.8 eV, which are in the range of the highest known electron affinities.
- Wang, Xuefeng,Andrews, Lester
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p. 3768 - 3771
(2011/04/26)
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- Aluminium-27 N.M.R. Studies of Aluminium Fluoro Complexes in Dichloromethane Solution: Evidence for the Tetrafluoroaluminate Anion
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Mixed aluminium chloro/fluoro anions are formed in dichloromethane solution by the interaction of AlCl3 and .Aluminium-27 n.m.r. studies are restricted to the stoichiometric ranges F/Al from 1:1 to 3:1 and F/Al>8:1.Between these limits rapid precipitation reactions occur.In the Fluoride-rich stoichiometric range there is rapid exchange on the n.m.r. time scale between the aluminium fluoro anion and free fluoride, so that a direct identification of the species by the multiplicity of the resonance is not possible.Indirect evidence strongly suggests that the aluminium species is -.In the F/Al stoichiometry range from 1:1 to 3:1 aluminium-27 resonances were observed for all the other possible - species.Studies on the aluminium iodo/fluoro system support the identification of -, but the system is labile and the mixed iodo/fluoro species undergo rapid disproportionation.
- Colton, Ray,Eller, Gary P.
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p. 1605 - 1610
(2007/10/02)
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- Raman spectroscopy of fluoride-containing chloroaluminate melts
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The effect of adding fluoride ions to chloroaluminate melts has been studied by Raman spectroscopy. In acidic (AlX3/MX mole ratio greater than 1, where M+ is an alkali-metal ion) melts at 200°C, the fluoride ion acts as a dibase and the new species Al2Cl6F- is formed, as indicated by comparison of observed and calculated frequencies. The polarization of the Raman bands indicates that a fluoride replaces a terminal chloride. Measurements have also been made on several basic melts (AlX3/MX mole ratio 4 with increasing amounts of NaF. It was found that fluoride replaces chloride progressively, depending on the molar ratio of NaF to NaAlCl4. The new species AlCl3F-, AlCl2F2-, and AlClF3-, together with the previously observed AlF4-, are clearly identified. Intensity measurements made on the characteristic bands allow a quantitative study of the distribution of each species as a function of melt composition. The calculated equilibrium constants follow the same trend as was found for similar chloro bromo species.
- Gilbert,Williams, Stephen D.,Mamantov
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p. 2359 - 2363
(2008/10/08)
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