Synthesis and Molecular Structure of Calcium Difluoranthenide, [Ca(THF) 6 ][C 16 H 10 ] 2 ·2C 16 H 10

The treatment of CaI 2 (THF) 2 with potassium and fluoranthene (mole ratio 1:2:2) in THF affords [Ca(THF) 6 ][C 16 H 10 ] 2 ·2C 16 H 10 ( 1 ). The X‐ray structure analysis of 1 shows that the compound consists of separate [Ca(THF) 6 ] 2+ cations, [C 16 H 10 ] · − radical anions and neutral fluoranthene molecules. The neutral and radical‐anionic fluoranthene species can be distinguished by the differences in the skeleton C−C bond lengths. The presence of fluoranthene radical anions in THF solutions of 1 is proved by ESR spectroscopy and is further supported by the 1 H NMR spectrum of 1 , which does not give any indication of radical coupling. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)