Synthesis and properties of benzophospholo[3,2-b]benzofuran derivatives.

Benzophospholo[3,2-b]benzofuran (BPBF) derivatives were studied as a new family of phosphole-containing π-conjugated organic materials. The versatile reactivity of the trivalent phosphorus center of the parent BPBF offered access to a variety of derivatives by simple chemical modifications. The diversity-oriented synthetic route was also developed to allow facile access to BPBFs with a different substituent on the phosphorus center. Photophysical properties were revealed based on UV-vis and photoluminescence spectroscopies and theoretical calculation. The characteristic property of BPBF derivatives is highly efficient photoluminescence. In particular, phosphole oxide derivatives demonstrated intense blue fluorescence with high quantum yield over 85% even in the solid state.