Naphthalene- and perylenediimides with hydroquinones, catechols, boronic esters and imines in the core
作者:Andrea Fin、Irina Petkova、David Alonso Doval、Naomi Sakai、Eric Vauthey、Stefan Matile
DOI:10.1039/c1ob05702b
日期:——
The green-fluorescent protein of the jellyfish operates with the most powerful phenolate donors in the push–pull fluorophore. To nevertheless achieve red fluorescence with the same architecture, sea anemone and corals apply oxidative imination, a process that accounts for the chemistry of vision as well. The objective of this study was to apply these lessons from nature to one of the most compact family of panchromatic fluorophores, i.e. core-substituted naphthalenediimides (cNDIs). We report straightforward synthetic access to hydroxylated cNDI and cPDI cores by palladium-catalyzed cleavage of allyloxy substituents. With hydroxylated cNDIs but not cPDIs in water-containing media, excited-state intramolecular proton transfer yields a second bathochromic emission. Deprotonation of hydroquinone, catechol and boronic ester cores provides access to an impressive panchromism up to the NIR frontier at 640 nm. With cNDIs, oxidative imination gives red shifts up to 638 nm, whereas the expanded cPDIs already absorb at 754 nm upon deprotonation of hydroquinone cores. The practical usefulness of hydroquinone cNDIs is exemplified by ratiometric sensing of the purity of DMF with the “naked eye” at a sensitivity far beyond the “naked nose”. We conclude that the panchromatic hypersensitivity toward the environment of the new cNDIs is ideal for pattern generation in differential sensing arrays.
水母的绿色荧光蛋白在推拉荧光团中使用了最强大的酚酸供体。然而,为了以相同的结构实现红色荧光,海葵和珊瑚采用了氧化模仿法,这一过程也是视觉化学的一个组成部分。本研究的目的是将自然界的这些经验应用于最紧凑的全色荧光团家族之一,即核心取代萘二亚胺(cNDIs)。我们报告了通过钯催化烯丙氧基取代基裂解羟基化 cNDI 和 cPDI 核心的直接合成途径。在含水介质中,对于羟基化的 cNDI 而非 cPDI,激发态分子内质子转移会产生第二次浴色发射。对苯二酚、邻苯二酚和硼酸酯核心的去质子化可产生令人印象深刻的全色性,最高可达 640 纳米的近红外波段。对于 cNDIs,氧化亚氨基化会产生高达 638 纳米的红移,而扩大的 cPDIs 在对苯二酚核去质子化后,吸收波长可达 754 纳米。对苯二酚 cNDIs 的实用性体现在用 "肉眼 "对 DMF 的纯度进行比率测量,其灵敏度远远超过了 "肉眼"。我们的结论是,新型 cNDI 对环境的全色超敏感性非常适合在差分传感阵列中生成模式。