Helge Willner

Trifluoroselenoacetic acid, CF(3)C(O)SeH: preparation and properties.

The hitherto unknown trifluoroselenoacetic acid was prepared through the reaction of trifluoroacetic acid with Woollins reagent. The compound was fully characterized by mass spectrometry, (1)H, (19)F, (77)Se, and (13)C NMR, UV-visible, IR and Raman spectroscopy, and the boiling point at 46 °C was estimated from the vapor pressure curve. An IR matrix isolation study revealed the presence of two different syn-anti and anti-syn conformers. The IR spectra of the two stereoisomers have been assigned, aided by DFT, and ab initio calculations. The UV photolysis of Ar matrix isolated CF(3)C(O)SeH yielded CO, OCSe, CF(3)SeH, and CHF(3). Apart from CF(3)SeH, these products were also obtained by vacuum flash-pyrolysis (310 °C) of gaseous CF(3)C(O)SeH. Instead of CF(3)SeH, CF(2)Se, and HF were detected among the pyrolysis products. The different decomposition pathways of CF(3)C(O)SeH are discussed.

Laser photoluminescence spectra of the M+S2− species in solid argon at 12K

Abstract Matrix reactions of alkali metal atoms with S 2 Cl 2 and photolyzed H 2 S samples have been examined by laser excitation at 457.9 nm. The strong photoluminescence spectrum from 12 300 to 18 300 cm −1 exhibited vibrational spacings near 550 cm −1 . Observation of the same ZPL spectrum with two different precursors identified the carrier as Na + S 2 − . The vibrational numbering was made possible by the Na + 32 S 34 S − species in natural abundance and from a 33% 34 S-enriched sample of S 2 Cl 2 . The spectroscopic constants ν 00 = 19 990 ± 10 cm − , ω 0 ″ = 586 ± 2 cm −1 and ω 0 x 0 ″ = 2.8 ± 0.2 cm −1 are in excellent agreement with those reported for S 2 − in alkali halide crystals at low temperature.