A Modular Approach to Phosphorescent π‑Extended Heteroacenes

A modular route to previously inaccessible classes of ring-fused π-extended heteroacenes bearing the heavy inorganic element tellurium (Te) is presented. These new materials can be viewed as n-doped analogs of molecular graphene subunits that exhibit color tunable visible light phosphorescence in the solid state and in the presence of air. The general mechanism of phosphorescence in these systems was probed experimentally and computationally via time-dependent density functional theory (TD-DFT). The incorporation of Te into π-extended oligoacene frameworks was achieved by an efficient Zr/Te transmetalation protocol; related zirconium-element exchange reactions have been used to prepare both electron-rich and electron-deficient heterocycles containing different elements from throughout the p-block. Therefore, the current study provides a clear path to incorporate inorganic elements into heteroacenes of greater complexity and side group selectivity compared to existing synthetic routes.本研究报道了一条模块化合成路线，可用于制备此前难以获取的一系列含重无机元素碲（Te）的稠环π扩展杂并苯。这类新型材料可被视为分子石墨烯亚单元的n型掺杂类似物，在固态及有氧环境中均能发射可调控颜色的可见光磷光。本研究通过实验结合含时密度泛函理论（TD-DFT）的计算手段，对该类体系的磷光通用机制进行了探究。通过高效的锆（Zr）/碲转金属化方法，可将Te引入π扩展寡并苯骨架；相关的锆-元素交换反应此前已被用于制备含p区不同元素的富电子与缺电子杂环。因此，与现有合成路线相比，本研究为将无机元素引入结构更复杂、侧基选择性更可控的杂并苯体系提供了清晰可行的路径。