(Poly)terephthalates with Efficient Blue Emission in the Solid State

Abstract

We prepared dimethyl and diaryl 2,5-dialkoxyterephthalates from dimethyl 2,5-dihydroxyterephthalate in good-to-high yields via alkylation or as equence of alkylation, hydrolysis, chlorination, and condensation. The absorption spectra of the dialkoxyterephthalates contain as mall band at 332-355nm, which could be assigned to intramolecular charge-transfert ransition from the alkoxy to alkoxycarbonyl groups on the basis of theoretical calculations using density functional theory.T he dialkoxyterephthalates exhibited blue fluorescencew ith moderate-to-excellent quantum yields not only in solution but also in the solid state, such as ap oly(methylm ethacrylate) (PMMA) film and ap owder.T he solid-state quantum yields of the diisopropoxy-substituted terephthalates were similaro rc onsiderably higher than those of the dimethoxy-substituted counterparts. Copolymerization of 2,5-diisopropoxyterephthaloyl chloridea nd 1,4-butanediol with or withoutt erephthaloyl chlorideg ave brilliantly blue fluorescent polymers, whose quantum yields were 0.72 and 0.71 in toluene and0 .46 and 0.40 in the neat film, respectively.F urthermore, white emission was achieved when af luorescent yellow 2,5-diaminoterephthalate was doped into the thin film of the blue fluorescent polymer at 0.4 wt %.Scheme1.Molecular structures of fluorescent (poly)terephthalates 1-3.[a] Prof.

The Journey to Precious‐Metal‐Free Organic Phosphors from Single‐Benzene‐Cored Fluorophores

“…Considering that 3 emits green‐to‐yellow fluorescence and the weakening of the donor, that is, an amino group, induces a hypochromic shift in the emission spectrum, we chose an alkoxy group as A in place of the amino group in 3G and developed 2,5‐dialkoxyterephthalates 5 as novel blue fluorophores, whose quantum yields ranged from 0.18–0.81 in powder and 0.19–0.64 in polymethylmethacrylate (PMMA) films (Figure 15). [24] The emission maxima of the diaryl esters 5 (R 2 =Ar) were bathochromically shifted compared to those of the dimethyl esters 5 (R 2 =Me). The quantum yields of diisopropoxy derivatives 5 (R 1 = i Pr) were similar to or much higher than those of dimethoxy derivative 5 (R 1 =Me).…”

Synthesis, Self‐assembly, and Fluorescence Application of Bottlebrush Polyfluorene‐g‐Polycaprolactone with Conjugated Backbone and Crystalline Brushes

“…But the creation of organic molecules that efficiently fluoresce in solid‐state is also an important research subject in the field of functional molecular materials. [ 27,28 ] This is because the creation of such novel fluorophores would lead to advances in organic solid‐state light‐emitting devices. [ 29 ] Thus, to suppress the aggregation of conjugated groups and enhance photoluminescence efficiencies are also the important ways for exploring the practical application of luminescent materials.…”

Dual-State Emission (DSE) in Organic Fluorophores: Design and Applications

“…For instance, Sakaguchi and co-workers reported a series of compounds ( 28a – 28j ) displaying DSE properties (Scheme ). The observed quantum yields ranged from Φ F = 8% to 95% in solution and Φ F = 18% to 81% in the solid state …”