Rubrene cation radical stabilized by polyiodide chains in the (rubrene)I-9 crystal

A fused polycyclic aromatic compound, rubrene (RB), has been found to form a charge-transfer compound with iodine with the stoichiometry of RB . I-9. The crystal is monoclinic, space group C2/c, a = 14.482(4), b = 16.676(8), c = 19.985(4) Angstrom, beta = 106.90(2)degrees, V = 4618(2) Angstrom(3), and Z = 4. In this crystal, a unique branched crank-shaped one-dimensional (I-9(-))(infinity) polyiodide chain is formed. RE is surrounded by the polyiodide, and its cation radical state, which is unstable under normal conditions, is stabilized. The formation of the RE cation radical has been confirmed by IR, VIS-NIR, and EPR spectroscopies. The magnetic susceptibility measurement has indicated the existence of superexchange interactions through the polyiodide.