A new class of polyiodide complexes of 5-dibenzosuberenone with iodine and alkali iodide (DIMI complexes, M = Na, K, Rb or Cs) has been prepared for the first time. The single crystals of the DIMI complexes are needle shaped with a shiny metallic luster along the needle axis. Their longitudial dc conductivities are in the order of 10−4 Scm−1 at room temperature. They behave in a semiconductive manner from 250 to 300 K with activation energies of 0.6 to 0.9 eV. Resonance Raman spectroscopic studies show that the iodine species exist as symmetric I3 − units in one-dimensional polyiodide chains, which are probably the conducting strands in these complexes.
Molecular crystals and liquid crystals 159, pp.315-322