Enhanced Electrical Conductivity in a Substitutionally Doped Spiro-bis(phenalenyl)boron Radical Molecular Solid

We
report the crystallization of a subsitutionally doped organic
conductor based on a host lattice composed of spiro-bis­(phenalenyl)­boron
radicals. Co-crystallization of solutions of spiro-bis­(9-oxido­phenalenone)­boron
radical [PLY­(O,O)]2B mixed with selected amounts of spiro-bis­(9-oxido­phenalenone)­beryllium
[PLY­(O,O)]2Be leads to the formation of a series of solid-state
solutions of composition [PLY­(O,O)]2­B(1–x)Bex. The dopant molecules
[PLY­(O,O)]2Be serve to introduce holes into the lattice
of spins provided by the [PLY­(O,O)]2B radicals and lead
to a systematic increase in the conductivity while decreasing the
activation energy of the conduction process and leaving the solid-state
structure relatively unperturbed. While the energies of the hole sites
are expected to be high, the results are consistent with the interpretation
of the electronic structure of [PLY­(O,O)]2B in terms of
the resonating valence bond model.