Systematic Evaluation of 2,6-Linked Pyridine–Thiophene Oligomers

An
efficient synthesis of alternating 2,6-linked pyridine–thiophene
(Py-Th) oligomers allows systematic evaluation of their optical and
electrochemical properties. The six- and eight-ring oligomers are
revealed to be brightly luminescent, even in the solid state. The
oligomers are easily reduced but cannot be electrochemically oxidized.
The longer oligomers have reduction potentials similar to those reported
for pyridine–thiophene polymers of less defined structure.
Protonation of the pyridine or substitution at C4 are shown to further
modulate the electronic properties and, in combination with the low-lying
absolute LUMO energies, these data suggest that the compounds are
potential n-type materials worthy of further study.