Novel naphthalimide derivatives (NIM) with donor–acceptor architecture were successfully constructed and their unique fluorescent properties were investigated. In particular, the fluorescence intensities of 4-methoxystyrene substituted NIM-1 were solvent independent and its quantum yields varied from 0.4 in toluene to 0.52 in MeOH. However, 4-(N,N-diphenylamino) styrene substituted NIM-2 and 4-nitrostyrene substituted NIM-3 exhibited low luminescence in dilute solutions but were efficiently fluorescent under conditions of molecular aggregation. NIM-2 showed strong solid fluorescence with a longer wavelength emission and larger Stokes shift. In addition, NIM-3 showed unexpected blue-green fluorescence due to the formation of fluorescent organic nanoparticles (FONs) under mixed solution. These two cases were ascribed to the aggregation-induced enhanced emission (AIEE) effects and which can also reasonably explain the bright cellular images observed when cells were incubated with NIM-2 and NIM-3. Furthermore, compound NIM-2 can be used to recognize cancer cells owing to its subcellular behaviour.
具有供体–受体结构的
萘酞亚
胺类衍
生物(NIM)成功合成,并研究了其独特的荧光特性。其中,
4-甲氧基苯乙烯取代的NIM-1的荧光强度与溶剂无关,量子产率在
甲苯中为0.4,在
甲醇中为0.52。然而,4-(N,N-二苯基
氨基)
苯乙烯取代的NIM-2和
4-硝基苯乙烯取代的NIM-3在稀溶液中发光较弱,但在分子聚集条件下荧光效率高。NIM-2在固体状态下显示强的长波长发射和较大的斯托克斯位移。此外,NIM-3在混合溶液中因形成荧光有机纳米颗粒(FONs)而显示出意外的蓝绿色荧光。这两个例子归因于聚集诱导增强发射(AIEE)效应,这也合理地解释了细胞与NIM-2和NIM-3共育时观察到的明亮的细胞图像。此外,由于其在亚细胞
水平上的行为,化合物NIM-2可用于识别癌细胞。