Novel h-shaped persistent architecture based on a dispiro building block system.

[structure: see text] A novel dispiro building block, dispiro[fluorene-9,5'(7'H)-diindeno[2,1-b:1',2'-d]thiophene-7',9' '-fluorene], and its two derivatives, TBP-DSFDITF and TDOF-DSFDITF, were designed and synthesized. Because of the rigidity and orthogonality of the spiro structure, TBP-DSFDITF exhibits a well-defined H-shaped architecture, which consists of two ter(biphenyls) as the arms of the H-shape and 3,4-diphenylthiophene as the rung, connecting via completely rigid dispiro linkages with two sp(3) carbon atoms.