AbstractA near‐infrared‐absorbing heptamethine (HM+) incorporating three bulky benzo[cd]indole heterocycles was designed to efficiently prevent self‐aggregation of the dye, which results in a strong enhancement of its photoinitiating reactivity as compared to a parent bis‐benzo[cd]indole heptamethine (HMCl+) used as a reference system. In this context, we highlight an efficient free‐radical NIR‐polymerization up to a 100 % acrylates C=C bonds conversion even under air conditions. Such an important initiating performance was obtained by incorporating our NIR‐sensitizer into a three‐component system leading to its self‐regeneration. This original photoredox cycle was thoroughly investigated through the identification of each intermediary species using EPR spectroscopy.
摘要 我们设计了一种具有近红外吸收能力的庚二胺(HM+),其中包含三个笨重的苯并[cd]
吲哚杂环,可有效防止
染料的自聚集,与用作参考体系的双苯并[cd]
吲哚庚二胺(HMCl+)相比,该
染料的光引发反应活性大大增强。在这种情况下,我们强调了一种高效的自由基近红外聚合反应,即使在空气条件下,
丙烯酸酯的 C=C 键转化率也能达到 100%。这种重要的启动性能是通过将我们的近红外敏化剂纳入一个三组分系统而获得的,该系统可实现近红外敏化剂的自我再生。通过使用 EPR 光谱鉴定每个中间物种,对这一原始光氧化循环进行了深入研究。