Synthesis and Semiconducting Characteristics of the BF2 Complexes of Bisbenzothiophene-Fused Azadipyrromethenes.

A novel type of dibenzothiophene [b]-fused core-expanded azaBODIPYs were obtained through an efficient post-functionalization of tetrabrominated azadipyrromethenes, using CuI-catalyzed cyclization, followed by BF2 complexation. These dyes show nearly planar skeletons, strong NIR absorption with maximum peaks up to 733 nm, and remarkable low-lying LUMO level of -4.15 eV. The field-effect transistor based on 1b exhibits bipolar transport properties, with the highest electron and hole mobilities up to 0.012 and 0.046 cm2 V-1 s-1, respectively.