Cryptatium: A Species of Expanded Atom/Radical Ion Pair Type from Electroreductive Crystallization of the Macrobicyclic Sodium Tris(Bipyridine) Cryptate
✍ Scribed by Prof. Dr. Luis Echegoyen; Dr. André DeCian; Prof. Dr. Jean Fischer; Prof. Dr. Jean-Marie Lehn
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 483 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0044-8249
No coin nor oath required. For personal study only.
✦ Synopsis
ure 3 shows that the voltammogram does not display any oxidation wave before background, even in the presence of cryptand, introduced to stabilize the oxidized form of the alkali cation.
The oxidation of Cse and the other alkali-metal ions in SO, is not unambiguous. It is surprising that Go, Na", and K0 are oxidized at the same potential, given their very different ionization potentials in the gas phase. However, salts from different origins show the same behavior, suggesting that a common impurity is unlikely. Water, the most likely candidate impurity, does not show this CV behavior, and the effect of added electrolyte suggests the oxidation wave can be attributed to a positive species.
Experimental Procedure
The measurements, the purification of SO,, and the preparation of the supporting electrolyte, nBu,NAsF, and the alkali salts (CsAsF,, RbAsF,, KAsF,) followed the procedure described previously [3,4]. NaPF6 (Aldrich) was used after recrystallization from Me,SO/CH,C12 and drying in a vacuum oven under the same conditions as above.
Experiments in MeCN were performed in a dry box (Vacuum Atmospheres) under a helium atmosphere using high-purity MeCN with a low concentration of water (0.003 %) (Burdick & Jackson). Kryptofix (Aldrich) and Woelm neutral activated alumina (ICN Biomedicals) were used as received. The supporting electrolyte, nBu,NPF6, was thrice recrystallized from EtOHITHF (1 :I), then dried in a vacuum oven and stored in the dry box.