Controlling the unpaired electron by electrostatic attraction in the solid state

One-electron reduction of 2,7-tBu2-pyrene-4,5,9,10-tetraone (1) with potassium afforded two monoradicals 1K(cryp) and 1K(18c6), a radical tetramer [1K(15c5)]4 and a radical polymer (1K)2n. From 1K(cryp) and 1K(18c6), we demonstrated large spin density modulation of an organic radical anion in the solid state by electrostatic attraction, without alternation of molecular skeletons.