Hydration of aqueous fluoride ions has been studied by theoretical ab initiocalculations in an attempt to understand the experimental Raman spectrum.Calculations for hydrated fluoride, F– (H2O)n where n = 1–10, have been performedat the RHF/6-31 + G* level. A relatively stable geometry exists for n = 6; abovethis number, additional waters hydrogen bond to water of the hydrated fluoride.On the long time scale of the ab initio calculation or experimental diffractionstudies, the average coordination of fluoride is 6. However, it has been possibleto interpret the low-frequency Raman spectrum on the basis of a singlehydrogen-bonded water molecule, F– ... HOH. To rationalize these results, it is proposedthat the average coordination of fluoride is 6, but on the time scale of the Ramanexperiment the fluoride is symmetrically bonded to only one hydrogen of onewater molecule.Chairman and Organizer of the Symposium dedicated to Donald Irish. Unfortunately Murray died during the preparation of this special issue 相似文献
A new chromogenic receptor based on 1,2-phenylene derivative containing thiourea moieties is synthesized and examined for its anion binding ability by UV–Vis and 1H NMR studies. The results show that the receptor has selective colorimetric sensing of fluoride over all other anions like chloride, bromide, iodide, nitrate, hydrogen sulphate and acetate. 相似文献
Summary: This paper reports a new and simple approach for the amplified detection of fluoride ions by a polymer‐based chemosensor made of stiff fluoroalkylated polysilane, poly(3,3,3‐trifluoropropylmethylsilane). This chemosensor exhibited extreme sensitivity and selectivity towards fluoride ions by a decrease in the photoluminescence (PL) intensity with parts per billion concentrations of fluoride ions in solution in tetrahydrofuran (THF). The quenching constant for fluoride ions (K = 1.35 × 107 M −1) was found to be exceptionally high.
Schematic representation of the polymer amplification mechanism after addition of fluoride ion in tetrahydrofuran. 相似文献