π‐Extended Pyrrole‐Fused Heteropine: Synthesis, Properties, and Application in Organic Field‐Effect Transistors

Abstract

Sulfur‐embedded polycyclic aromatic compounds have been used as building blocks for numerous organic semiconductors over the past few decades. While the success is based on thiophene‐containing compounds, aromatic compounds that contain thiepine, a sulfur‐containing seven‐membered‐ring arene, has been less well investigated. Here we report the synthesis and properties of π‐extended pyrrole‐fused heteropine compounds such as thiepine and oxepine. A π‐extended pyrrole‐fused thiepine exhibited a “pitched π‐stacking” structure in the crystal, and exhibited a high charge carrier mobility of up to 1.0 cm2 V−1 s−1 in single‐crystal field‐effect transistors.

Oxepine-Based π-Conjugated Ladder/Step-Ladder Polymers with Excited -State Aromaticity

“…39,40 The exploration of oxepine in functional electronic materials or in polymers is extremely rare. 41 Recently, triptycene-22 and spirobiindane-based 24,26 ladder polymers with enantiopure helical ribbon/tube have been realized using the above-mentioned acid-induced electrophilic cyclization reaction as the postpolymerization annulation. This approach has broad utility in quantitative regioselective ring formation to produce ladder polymers.…”

“…Oxepine plays an important role in the biosynthesis and metabolism of cyclic aromatic compounds and as core skeleton of natural products with pharmacological activity . As a result, most research studies on oxepine over decades have been confined in the total synthesis of known natural products, with new synthetic methodology − directed toward exploiting its biological activity. , The exploration of oxepine in functional electronic materials or in polymers is extremely rare …”