The preparation of large rylenes often needs the use of solubilizing groups along the rylene backbone, and all the substituents of the terrylenes and quaterrylenes were introduced before creating the rylene skeleton. In this work, we successfully synthesized 2,5,10,13-tetrakis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)terrylene (TB4) by using an iridium-catalyzed direct borylation of C–H bonds in terrylene in 56% yield. The product is soluble in common organic solvents and could be purified without column chromatography. Single crystal X-ray diffraction analysis revealed that the terrylene core is not disturbed by the substituents and is perfectly flat. The photophysical properties of TB4 are also unchanged by the substituents because the carbon atoms at 2,5,10,13-positions have less coefficients on its HOMO and LUMO, estimated by theoretical calculations. Finally, the same borylation reaction was applied for quaterrylene, resulting in the formation of soluble tetra-borylated quaterrylene despite a low yield. The post modification of rylenes enables us to prepare their borylated products as versatile units after creating the rylene skeletons.
通常需要在大型莱因的制备过程中沿着莱因骨架使用可溶性基团,并且在创建莱因骨架之前引入了所有四苯并莱因和四苯并四苯并莱因的取代基。在这项工作中,我们通过使用铱催化的莱因中C-H键的直接硼化反应,成功地合成了2,5,10,13-四(4,4,5,5-四甲基-1,3,2-二氧杂硼杂环戊二烷基)四苯并莱因(TB4),收率为56%。该产物在常见有机溶剂中溶解,并且可以在不进行柱层析的情况下纯化。单晶X射线衍射分析显示,莱因核心不受取代基的干扰,并且完全平坦。由于2,5,10,13-位置的碳原子在其HOMO和LUMO上具有较低的系数,根据理论计算,TB4的光物理性质也不受取代基的影响。最后,相同的硼化反应也用于四苯并莱因,尽管收率较低,但形成了可溶性的四硼代四苯并莱因。莱因的后修饰使我们能够在创建莱因骨架后将其硼化产物作为多功能单元进行制备。