Synthesis of Novel Hemicyanine Dyes for Color Compensating Film in Plasma Display Panels

Abstract

Five novel cyanine dyes containing julolidine and indole moieties were synthesized. Several color compensating films for plasma display panels (PDP) were prepared using these dyes. The spectroscopic and physicochemical properties of the synthesized dyes in both solution and film state were evaluated. For each color compensating film, the optimum ratio of dye to binder was determined on the basis of transmittance, half band width, and photo-stability of the color compensating film. The five synthesized dyes showed sharp absorption peaks near 590 nm (orange light) and had molar extinction coefficients above 1 × 10. The melting point of the dyes was above 200 o C and photo-stability of the color compensating films was improved by introducing substituents at the 5th position on the indole derivatives.

Synthesis and Derivatization of Julolidine: A Powerful Heterocyclic Structure

“…By means of such strategy, 9‐formyljulolidine 129a (Scheme ) and 8‐hydroxy‐9‐formyljulolidine 134 were obtained in different yields, depending on the reaction conditions employed. To the synthesis of 129a , the authors used as solvent CH 2 Cl 2 (r.t., 1–16 h; 60–95 % yield), , , or DMF (0 °C to r.t., 12 h; 67.3 % yield) and (0 °C to 80–100 °C, 2–4.5 h; 42.7–93 % yield) . Julolidine 134 was obtained in 65–97.6 % yield using POCl 3 and DMF at 0–4 °C to r.t. (overnight; 84 % yield), 60 °C (4 h; 80 % yield) or 80–100 °C (0.5 h; 65–97.6 % yield) , , , , .…”

“…Heterocyclic salts and cations derived from julolidines have also been produced through aldol condensation reactions from 9‐formyljulolidines (Table ). For example, indolium iodides 256a – e and 256f were used as nucleophile to produce 248a – e and 249a ‐ d , respectively (Table , Entries 1 and 2) , . In the first example, modest yields were obtained (30–34 %) by the use of acetic anhydride in 5 minutes reaction (Table , Entry 1) .…”

“…For example, indolium iodides 256a – e and 256f were used as nucleophile to produce 248a – e and 249a ‐ d , respectively (Table , Entries 1 and 2) , . In the first example, modest yields were obtained (30–34 %) by the use of acetic anhydride in 5 minutes reaction (Table , Entry 1) . In the second work, good yields (66–75 %) could be achieved by using pyridine and 1‐methoxypropan‐2‐ol, but with a larger reaction time (Table , Entry 2) .…”

“…Compounds 248a – e were used to produce color compensation films with maximum wavelengths of 592–604 nm which can be used in PDP (plasma display panelTV) …”