The use of cheap and safe near-infrared (NIR) light is still the subject of intense research efforts but remains a huge challenge due to the associated low photon energy (wavelength from 0.78 to 2.5 µm). In this study, a series of 17 NIR dyes mainly based on a well-established cyanine scaffold is proposed. Remarkably, 11 of them were never synthesized before. Markedly, noncharged structures, negatively charged cyanine bearing Na⁺ as counter cation, and positively charged cyanines bearing (B(Ph)₄⁻) or (I⁻) as counter anions were examined as promising NIR light photoinitiating systems. Excellent photoinitiating abilities were found for some reported dyes when used in combination with iodonium salt and amine. Markedly, photothermal effects with a huge heater behavior were also observed for different NIR dye structures. Interestingly, the synthesis of interpenetrating polymer networks (IPNs, e.g., for the polymerization of acrylate/epoxy monomer blends) can also be carried out upon NIR light with the proposed systems.

中文翻译：

---

开发用于自由基光聚合工艺的新型 NIR 染料

使用廉价且安全的近红外 (NIR) 光仍然是密集研究工作的主题，但由于相关的低光子能量（波长从 0.78 到 2.5 µm）仍然是一个巨大的挑战。在这项研究中，提出了一系列 17 种 NIR 染料，主要基于成熟的花青支架。值得注意的是，其中 11 个以前从未合成过。显着地，不带电荷的结构，带负电荷的花青带有作为抗衡阳离子的Na ⁺，带正电荷的花菁带有(B(Ph) ₄ ^- ) 或 (I ^-) 作为抗衡阴离子被认为是有前途的 NIR 光光引发系统。当与碘鎓盐和胺结合使用时，发现一些报道的染料具有优异的光引发能力。值得注意的是，对于不同的 NIR 染料结构，还观察到了具有巨大加热器行为的光热效应。有趣的是，互穿聚合物网络（IPN，例如，用于丙烯酸酯/环氧单体混合物的聚合）的合成也可以在 NIR 光下使用所提出的系统进行。