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 σRT = 4 × 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.