New dispiro compounds: synthesis and properties.

We report the synthesis and structural characterization of two dispiro compounds. These two positional isomers have been designed and synthesized through an efficient method. Because of the rigidity and orthogonality of the spiro bridge, both molecules exhibit a well-defined architecture which consists of two fluorene rings connecting to an indenofluorenyl unit via two sp3 carbon atoms. The structural, electrochemical, optical, and thermal properties of these dispiro isomers are discussed.