We have synthesized a series of oxadiazole compounds and ethynylene analogs. Our data reveal that the ring is both optically transparent in the visible range and fully conjugating while we have also discovered the presence of a non-radiative mechanism active in molecules containing common para-dialkoxy substituents adjacent to the oxadiazole ring(s). This structure leads to a greatly reduced quantum yield, in our example dropping from 95.0% to 48.0%. Through our thorough study we have revealed evidence that this is the result of a repulsive interaction between the oxadiazole and the adjacent alkoxy oxygen atom, which we believe prevents excited-state planarity. This quantum yield reduction is preventable through the design principles presented here.
我们合成了一系列氧杂二唑化合物和
乙炔类似物。我们的数据显示,该环在可见光范围内具有光学透明性并且完全共轭,同时我们还发现含有常见的对位二烷氧取代基的分子中存在一种非辐射机制。这种结构导致量子效率大幅下降,在我们的例子中,从95.0%降至48.0%。通过我们的深入研究,我们揭示了这导致的证据,认为这是由于氧杂二唑与相邻的烷氧氧原子之间的排斥相互作用,这种相互作用我们认为阻碍了激发态的平面性。通过这里提出的设计原则,可以防止这种量子效率的降低。