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.