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)] 2 is a dimer with an open-shell ground state. Compounds IF .- Na + (15-c-5) and IF .- K + (cryptand) are monoradical anion salts: IF 2 .- Li + possesses unique π-stack structure with an interplanar separation less than 3.46 Å, making it a semiconductor (δ RT =1.9×10 -4  S ⋅ cm -1 ). This work gives insights into multifunctional radical anions, and describes the design and development of different functional radicals.