Hydrothermal Syntheses, Structures, and Fluorescence Spectroscopy of New One-Dimensional Uranium Oxyfluorides Built from Edge-Sharing [UO2F5] Pentagonal Bipyramids
✍ Scribed by Philip M. Almond; Catherine E. Talley; Amanda C. Bean; Shane M. Peper; Thomas E. Albrecht-Schmitt
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 212 KB
- Volume
- 154
- Category
- Article
- ISSN
- 0022-4596
No coin nor oath required. For personal study only.
✦ Synopsis
Three new one-dimensional uranium oxy6uorides, (C 5 H 14 N 2 ) U 2 O 4 F 6 (AU1-3), (C 5 H 6 N)UO 2 F 3 (AU1-4), and (C 3 H 5 N 2 ) UO 2 F 3 (AU1-5), have been prepared from the reactions of UO 3 with HF and homopiperazine (C 5 H 12 N 2 ), pyridine, or pyrazole at 1803C in aqueous media. In all cases, the compounds were isolated in high yield in the form of large single crystals. Single crystal X-ray di4raction, elemental analysis, and 6uorescence spectroscopy have been used to characterize these compounds. Each structure contains linear one-dimensional chains formed from edge-sharing [UO 2 F 5 ] pentagonal bipyramids with substantial hydrogen-bonding occurring between the protonated organic cations and the anionic chains. AU1-4 and AU1-5 luminesce brightly when irradiated with 365 nm UV light, while emission is considerably weaker from AU1-3. An energy transfer mechanism between the pyridinium and pyrazolium cations and the UO 2؉ 2 groups in AU1-4 and AU1-5, respectively, is proposed to account for some of these di4erences.