Abstract With the fast development of the long-wavelength irradiation sources, such as light emitting diodes (LED), which possess advantages regarding irradiation safety and energy utilization efficiency, it is highly desired to develop efficient photobase generators (PBGs) sensitive to visible light. Currently, the reported efficient visible light PBGs mainly undergo photodecarboxylation to generate the super bases, while the released CO2 can potentially cause bubbles and cracks in the cured materials. Moreover, these ionic PBGs generally have poor solubility in organic media and limited thermal stability. In the present work, we have investigated a nonionic amidine PBG TX-DBN, which contains thioxanthone as a chromophore and a reduced form of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) as a latent base species. TX-DBN, with a strong absorption above 380 nm, showed excellent solubility in most organic solvents and commercial monomers/oligomers. Under irradiation with an LED lamp at 405 nm, TX-DBN undergoes a C N bond cleavage followed by a fast hydrogen transfer, leading to the generation of the super base DBN without the generation of CO2. The as-released active species, namely super bases and active free radicals, can trigger thiol-epoxy and thiol-ene polymerization to fabricate hybrid network.

中文翻译：

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噻吨酮基脒：一种高效的非离子光产碱剂，可在可见光 LED 光下进行基于硫醇的点击聚合

摘要 随着发光二极管（LED）等长波长辐照源在辐照安全性和能量利用效率方面的优势得到快速发展，迫切需要开发对可见光敏感的高效光产碱剂（PBGs）。目前，报道的高效可见光 PBG 主要通过光脱羧生成超碱，而释放的 CO2 可能会导致固化材料中的气泡和裂纹。此外，这些离子 PBG 通常在有机介质中的溶解性较差，热稳定性有限。在目前的工作中，我们研究了一种非离子脒 PBG TX-DBN，它含有噻吨酮作为发色团和 1,5-二氮杂双环 [4.3.0] 非 5-烯 (DBN) 的还原形式作为潜在碱物质. TX-DBN，在 380 nm 以上有很强的吸收，在大多数有机溶剂和商业单体/低聚物中显示出极好的溶解性。在 405 nm 的 LED 灯照射下，TX-DBN 发生 CN 键断裂，随后发生快速氢转移，导致生成超碱 DBN 而不产生 CO2。释放的活性物质，即超碱和活性自由基，可以触发硫醇-环氧和硫醇-烯聚合以制造混合网络。