Synthesis and Invesitigation of New, LED-Activatable Photoinitiators for Surface Refinement

拟议的项目有两个研究目标。第一步是合成新的双酰基磷化氧化物RPO（COR’）2，并对磷结合取代基R进行系统修饰。根据量子化学计算，取代基R对酰基磷化物的光化学性质起重要作用。随后将研究新合成的化合物作为光引发剂在广泛使用的材料木材、皮革和金属（钛）的新型表面功能化中的应用。在这里，丙烯酸酯的聚合应该用可见光通过固定光活性磷化合物在各自的表面上触发。由此产生的混合材料（由有机聚合物层涂覆的天然基材）以其改进的性能而闻名，从而推动了对第二部分，特别是科学创新部分的进一步高效光引发剂的探索。后者的重点是合成新的，led活化和水溶性钛和硅化合物。在钛的情况下，由于与BAPOs （P-C键）相比，它们更容易切割Ti- c键，因此可以设想具有通式Ti(acac)2(COR)2 （acac =乙酰丙酮）的酰基钛酸盐。这种双酰基钛酸盐早在40年前就已经为其合成和探索奠定了良好的基础，但到目前为止，文献中还没有发现。除了钛化合物外，还将合成和表征一些硅基光引发剂作为光固化材料的添加剂。在具有光活性的四（酰基）硅烷中，用具有吸电子取代基的芳基取代二甲氧基部分应能更有效地吸收LED聚合灯发出的光。为了实现酰基硅烷的选择性固定化，本文合成并研究了一类通式为RSi（COR’）3的新型化合物。这两种方法的结合（引入吸电子基团和RSi（COR’）3的功能化，取代基R适合表面固定）将对基础研究做出有价值的贡献，并为一种全新的表面细化的高效光引发剂铺平道路。

The proposed project pursues two research aims. The first one deals with the synthesis of new bisacylphosphane oxides (BAPOs) RPO(COR`)2 that will be accompanied by a systematic modification of the phosphorus bound substituent R. According to quantum chemical calculations, the substituent R plays an important role for the photochemical properties of the acylphosphanes. The newly synthesized compounds will subsequently be investigated with regard to their application as photoinitiators in novel surface functionalizations of the widely used materials wood, leather and metal (titanium).Herein, polymerization of acrylate should be triggered with visible light by immobilizing photoactive phosphorus compounds on the respective surface. The resulting hybrid materials (natural substrates coated by an organic polymer layer) are known for improved properties, thus motivating the exploration of further efficient photoinitiators in the second, particularly scientifically innovative part of the project.The latter focuses on the synthesis of new, LED-activatable and water soluble titanium and silicon compounds. In the case of titanium, acyltitanates with the general formula Ti(acac)2(COR)2 (acac = acetylacetonate) will be envisioned due to their easier cleavable Ti-C bond if compared to BAPOs (P-C bond). Up to the present, such bisacyltitanates are not known in literature even though a promising foundation for their synthesis and exploration has already been laid 40 years ago.In addition to the titanium compounds, a number of silicon-based photoinitiators as additives in light curing materials will be synthesized and characterized. The substitution of mesityl moieties by aryl groups with electron withdrawing substituents in a photoactive tetra(acyl)silane should result in a more efficient absorption of the light emitted by a LED polymerization lamp. In order to enable a selective immobilisation of the acylsilanes, a new compound class of the general formula RSi(COR`)3 will be synthesized and investigated. The combination of these two approaches (the introduction of electron withdrawing groups and the functionalization of RSi(COR`)3 with a substituent R being suitable for surface fixation) will both valuably contribute to the fundamental research and pave the way for an entirely new type of efficient photoinitiators for surface refinement.