A novel symmetrical 2,10-bis-styryl-1-benzopyrylium dye was synthesized through two steps: In the first reaction an aldol condensation between 2,4,6-trihydroxybenzaldehyde and 3,4-dihydroxy­methylstyrylketone gave 5,7,3′,4′-tetrahydroxy-2-styryl-1-benzopyrylium; and in the second step this latter reacted with the same ketone by a cycloaddition reaction yielding the symmetrical 2,10-bis(3,4-di­hydroxystyryl)-pyrano-7-hydroxy-1-benzopyrylium. The dye was fully characterized by LC-DAD/ESI-MS and NMR 1D and 2D techniques, and a formation pathway was proposed. The novel dye obtained revealed extended π-conjugation (λmax 556 nm) and catechol groups in its composition, which is very important for applications as a photosensitizer for dye-sensitive solar cells (DSSCs).

中文翻译：

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新型对称 2,10-Bis-Styryl-1-Benzopyrylium 染料的合成和结构表征

通过两个步骤合成了一种新型对称 2,10-双-苯乙烯基-1-苯并吡喃染料：在第一个反应中，2,4,6-三羟基苯甲醛和 3,4-二羟甲基苯乙烯基酮之间的醛醇缩合得到 5,7,3'， 4'-四羟基-2-苯乙烯基-1-苯并吡喃鎓；在第二步中，后者通过环加成反应与相同的酮反应，产生对称的 2,10-双（3,4-二羟基苯乙烯基）-吡喃并-7-羟基-1-苯并吡喃鎓。该染料通过 LC-DAD/ESI-MS 和 NMR 一维和二维技术进行了充分表征，并提出了形成途径。获得的新型染料在其组成中显示出扩展的 π 共轭（λmax 556 nm）和邻苯二酚基团，这对于作为染料敏感太阳能电池（DSSC）的光敏剂的应用非常重要。