Resonating valence bond ground state in oxygen-functionalized phenalenyl-based neutral radical molecular conductors.
We report the preparation, crystallization, and solid-state characterization of the first two members of a new family of spiro-bis(1,9-disubstituted phenalenyl)boron neutral radicals based solely on oxygen functionalization, and we show that this strategy significantly lowers the electrochemical disproportionation potentials (DeltaE), in comparison with other spiro-bis(1,9-disubstituted phenalenyl)boron salts. In the solid state, these radicals pack in a continuous array of pi-pi-stacked phenalenyl units with very short intermolecular carbon...carbon contacts. These two radicals are among the most highly conducting neutral organic solids, with room temperature conductivities reaching 0.3 S/cm. Magnetic susceptibility measurements show that the radicals do not exist as isolated free radicals, and there is significant spin-spin interaction between the molecules in the solid state as expected from the crystal structures and the calculated band structures; the solid-state properties are best rationalized in terms of the resonating valence bond model.
Mandal
Swadhin K
SK
Departments of Chemistry, Chemical & Environmental Engineering, University of California, Riverside, CA 92521-0403, USA.
Samanta
Satyabrata
S
Itkis
Mikhail E
ME
Jensen
Dell W
DW
Reed
Robert W
RW
Oakley
Richard T
RT
Tham
Fook S
FS
Donnadieu
Bruno
B
Haddon
Robert C
RC