Indeno[2,1-a]fluorene-11,12-dione Radical Anions: Synthesis, Characterization, and Properties.

The one-electron reduction of indeno[2,1-a]fluorene-11,12-dione (IF) with various alkali metals prepare the radical anion salts. The data about different structures, properties, and characterization was obtained by single-crystal X-ray diffraction, electron paramagnetic resonance (EPR) spectroscopy, superconducting quantum interference device (SQUID) measurements, and physical property measurement system (PPMS). Compound IF K (18-c-6) is regarded as a one-dimensional magnetic chain through C-H⋅⋅⋅C interaction. Theoretical calculations and magnetic results showed that [IF K (15-c-5)] is a dimer with an open-shell ground state. Compounds IF Na (15-c-5) and IF K (cryptand) are monoradical anion salts: IF Li possesses unique π-stack structure with an interplanar separation less than 3.46 Å, making it a semiconductor (δ =1.9×10  S ⋅ cm ). This work gives insights into multifunctional radical anions, and describes the design and development of different functional radicals.