New family of aminophenalenyl-based neutral radical molecular conductors: synthesis, structure, and solid state properties

We report the preparation, crystallization, and solid-state characterization of the first members of a new family of spiro-bis-(1,9-diamino-substituted-phenalenyl)boron neutral radicals. The crystal structures show that the three radicals are monomeric and without close contacts in the crystal lattice. In all cases magnetic susceptibility measurements confirm the presence of free radicals with one unpaired spin per molecule. Two of the new radical compounds are among the most highly conducting neutral organic solids, with room-temperature conductivities reaching sigma(RT) = 4 x 10(-2) S/cm. The measured conductivities correlate with the closest intermolecular contacts in the solid state and with the calculated band dispersions, even though the bandwidths are much smaller than those found in other organic conductors.