Visible light induced synthesis generally involves i) dyes or chromophores with potential photocleavable bonds (Type I photoinitiator), ii) hydrogen abstractions (Type II photoinitiator) by dyes/chromphores and iii) photoredox catalysis using metal-based or metal-free dyes. Beyond these strategies, charge transfer complexes (CTCs), also referred to as electron donor acceptor (EDA) complexes, were also reported to be the visible light initiating species. In these cases, the ground state intimate association of a donor and acceptor creates a new structure that can result in (bathochromic) visible light absorption compared to the separated compounds. In the present review, an update on CTCs as photoinitiating systems for photopolymerization applications will be provided with examples of CTC-specific structure/reactivity/efficiency relationships. Interestingly, CTC can act as dual photo/thermal photoinitiators both in cationic and free radical photopolymerizations. Also, low optical density of the CTC in resins allowed to access extremely thick samples and composites. The possibility of extending wavelength sensitivity of photopolymerizations by excited state complexes (exciplexes) is also discussed.

可见光诱导的合成通常涉及i）具有潜在光裂解键的染料或生色团（I型光引发剂），ii）氢抽象（II型）光引发剂）通过染料/染料和iii）使用金属基或无金属的染料进行光氧化还原催化。除这些策略外，还据报道电荷转移复合物（CTC）也称为电子供体受体（EDA）复合物，是可见光引发物种。在这些情况下，供体和受体的基态紧密结合会产生新的结构，与分离的化合物相比，该结构可导致（发色）可见光吸收。在本综述中，将提供有关CTC的更新（作为用于光聚合应用的光引发系统），以及CTC特定结构/反应性/效率关系的示例。有趣的是，CTC可以在阳离子和自由基光聚合反应中充当双重光/热光引发剂。也，树脂中四氯化碳的光密度低，因此可以获取极厚的样品和复合材料。还讨论了通过激发态络合物（激基复合物）扩展光聚合反应波长敏感性的可能性。