Isomerically Pure Anthra[2,3‑b:6,7‑b′]-difuran (anti-ADF), -dithiophene (anti-ADT), and -diselenophene (anti-ADS): Selective Synthesis, Electronic Structures, and Application to Organic Field-Effect Transistors
A new straightforward synthesis of isomerically pure
anthra[2,3-b:6,7-b′] -difuran
(anti-ADF), -dithiophene (anti-ADT),
and -diselenophene
(anti-ADS) from readily available 2,6-dimethoxyanthracene
is described. The present successful synthesis makes it possible to
overview the linear-shaped anti-acenedichalcogenophene
compounds, that is, benzo[1,2-b:4,5-b′]-, naphtho[2,3-b:6,7-b′]-, and anthra[2,3-b:6,7-b′]- difuran, -dithiophene, and -diselenophene. By comparing
their electrochemical and photochemical properties, the electronic
structures of acenedichalcogenophenes can be expressed as the outcome
of balance between the central acene core and the outermost chalcogenophene
rings. Among isomerically pure parent anti-anthradichalcogenophenes, anti-ADT and anti-ADS can afford crystalline
thin films by vapor deposition, which acted as active layer in organic
field-effect transistors with mobility as high as 0.3 cm2 V–1 s–1 for ADT and 0.7 cm2 V–1 s–1 for ADS. The
mobility of isomerically pure anti-ADT is higher
by several times than those reported for isomercally mixed ADT, implying
that the isomeric purity could be beneficial for realizing the better
FET mobility. We also tested the diphenyl derivatives of anti-ADF, -ADT, and -ADS as the active material for OFET devices, which
showed high mobility of up to 1.3 cm2 V–1 s–1.