Synthesis of a 4,9-Didodecyl Angular-Shaped Naphthodiselenophene Building Block to Achieve High-Mobility Transistors

A new tetracyclic 4,9-dialkyl angular-shaped naphthodiselenophene (4,9-α-aNDS) was designed and synthesized. The naphthalene core in 4,9-α-aNDS is formed by the DBU-induced 6π-cyclization of an (E)-1,2-bis(3-(tetradec-1-yn-1-yl)selenophen-2-yl)ethene intermediate followed by the second PtCl₂-catalyzed benzannulation. This synthetic protocol allows for incorporating two dodecyl groups regiospecifically at 4,9-positions of the resulting α-aNDS. An ordered supramolecular self-assembly formed via noncovalent selenium-selenium interactions with a short contact of 3.5 Å was observed in the single-crystal structure of 4,9-α-aNDS. The distannylated α-aNDS building block was copolymerized with Br-DTFBT and Br-DPP acceptors by Stille cross coupling to form two new donor-acceptor polymers PαNDSDTFBT and PαNDSDPP, respectively. The bottom-gate/top-contact organic field-effect devices using the PαNDSDTFBT and PαNDSDPP semiconductors accomplished superior hole mobility of 3.77 and 2.17 cm² V^-1 s^-1, respectively, which are among the highest mobilities reported to date.