Thiophene-Fused 1,10-Phenanthroline and Its Conjugated Polymers

A novel type of π-extended
1,10-phenanthroline, specifically
with fused thiophene groups at the less exploited 3-, 4-, 7-, and
8-positions of the phenanthroline ring, and its conjugated polymers
were designed and synthesized. The current developed route is based
on the Bischler–Napieralski cyclization of the (1,2-phenylene)­diamide
precursor, which offers a facile and versatile strategy for preparing
soluble and well-defined 1,10-phenanthroline derivatives and their
analogues. High molecular weight poly­(phenanthroline-co-fluorene)­s with good solubility in common organic solvents or water
were prepared by palladium-catalyzed Suzuki–Miyaura–Schlüter
polycondensation. The optical responsive properties of these thiophene-fused
1,10-phenanthroline-containing polymers have demonstrated these polymers
could be a good candidate for potential applications as luminescent
chemosensor materials thanks to the specific repeating unit along
the backbone.