The
logical design for obtaining a blue-luminescent film based
on a conjugated polymer is demonstrated. We recently found solid-state
luminescent boron complexes with fused ketoiminate ligands (FBKIs).
From quantum chemical calculations, it was proposed that there is
a skeletal carbon having isolated highest occupied molecular orbital
(HOMO) where the lobe in HOMO and the node in lowest unoccupied molecular
orbital (LUMO) exist. From these results, we presumed that only the
HOMO energy level could be selectively lowered by aza-substitution
at this carbon atom. Based on this idea, we designed and synthesized
the aza-substituted FBKI (azaFBKI). From the optical and electrochemical
measurements, it was shown that azaFBKIs had solid-state luminescent
properties and especially the wider energy gaps originating from the
lower HOMO levels than the corresponding FBKIs. Next, the conjugated
homopolymer including azaFKBI as a repeating unit was designed and
obtained. Finally, it was observed that the synthesized polymer exhibited
purely blue luminescence in film (λem = 440 nm, ΦPL,film = 0.48, CIE; 0.19, 0.18).