Three styrylbenzoxazole derivatives with terminal dicyanomethylene group were studied in order to understand how minor modifications brought to the benzoxazole ring influence the photoluminescence (PL) properties. The three compounds, in which several molecular motions are allowed, were weakly fluorescent in organic solution. Remarkably, the unsubstituted (1) and methoxy (2) derivatives showed clear solid-state luminescence enhancement (SLE). Distinct emission characteristics were attributed to the formation of amorphous and crystalline particles owing to scanning electron microscopy. These two compounds were also strongly luminescent as microcrystalline powders. Compound 1 that crystallized in herringbone configuration was a better emitter than the methoxy derivative 2, in which intermolecular interactions are more numerous, according to X-ray diffraction analysis. In contrast, compound 3 was virtually not emissive, confirming that in this series of dyes the presence of the hydroxy group is detrimental to PL emission, as rarely observed among SLE-active fluorophores.

为了了解带有苯并恶唑环的微小修饰如何影响光致发光（PL）性能，对三种带有末端二氰基亚甲基的苯乙烯基苯并恶唑衍生物进行了研究。允许几种分子运动的这三种化合物在有机溶液中的荧光较弱。值得注意的是，未取代的（1）和甲氧基（2）衍生物显示出明显的固态发光增强（SLE）。由于扫描电子显微镜，不同的发射特性归因于非晶和结晶颗粒的形成。这两种化合物也以微晶粉末的形式强烈发光。化合物1根据X射线衍射分析，以人字形构型结晶的是比甲氧基衍生物2更好的发射体，后者之间的分子间相互作用更多。相反，化合物3实际上是不发光的，证实了在这一系列染料中，羟基的存在对PL发射有害，这在SLE活性荧光团中很少见到。