Three novel oxime esters based on the π-conjugated trans-stilbene group were designed and synthesized as photoinitiators (PIs) for light-emitting diode (LED) photopolymerization. Three substituents (thioether, sulfoxide, and sulfone) with different electron pushing and withdrawing abilities were introduced into the chromophore to constitute D-π-A (OXE-S) and A-π-A (OXE-SO, OXE-SO₂) type structures of PIs to rationalize their relevant effects on free radical photoinitiation ability. Structure-activity relationship, electronic properties, and photodissociation mechanism were investigated using steady-state photolysis, density functional theory (DFT) calculations, and real-time ¹H NMR. The compounds show good absorption under exposure to LED irradiation wavelength (i.e., 365–405 nm). The polarity of solvent influences the photoreactivity of this series of oxime esters. The photolysis rates and free radical generation quantum yields for the three PIs increase from polar to nonpolar solvent. For D-π-A type OXE-S, the photolysis rate increases 70 times from acetonitrile to toluene. The three PIs can efficiently initiate the polymerization of acrylate monomer under exposure to LED irradiation at 365–405 nm. The excellent absorption and efficient photoinitiation properties of the PIs demonstrate their great potential in photocuring applications.

设计并合成了三种基于 π-共轭反式二苯乙烯基团的新型肟酯作为发光二极管 (LED) 光聚合的光引发剂 (PI)。将具有不同推电子能力的三种取代基（硫醚、亚砜和砜）引入发色团，构成 D-π-A (OXE-S) 和 A-π-A (OXE-SO, OXE-SO ₂ ) PIs 的类型结构，以合理化它们对自由基光引发能力的相关影响。使用稳态光解、密度泛函理论 (DFT) 计算和实时¹核磁共振。这些化合物在暴露于 LED 照射波长（即 365–405 nm）下显示出良好的吸收。溶剂的极性影响该系列肟酯的光反应性。从极性溶剂到非极性溶剂，三种 PI 的光解速率和自由基产生量子产率增加。对于D-π-A型OXE-S，光解速率从乙腈到甲苯提高了70倍。在 365-405 nm 的 LED 照射下，这三种 PI 可以有效地引发丙烯酸酯单体的聚合。PI 优异的吸收性和高效的光引发性能证明了它们在光固化应用中的巨大潜力。