Room-temperature phosphorescence properties from cyclodextrin inclusion complexes in solutions

在室温下，通常不能观察到溶液中芳香族化合物的磷光。然而，位于环糊精(CD)包合物中的客体的室温磷光(RTP)经常被观察到。到目前为止，除了α-CD-6-溴-2-萘酚和α-CD-2-氯萘包合物外，β-和伽马-镉(衍生物)被称为发射RTP的镉包合物。在β-和伽马-镉的情况下，包含单个CD分子的包合物发出客体的RTP。另一方面，对于α-CD，2：1的a-CD-客体包合物单独发射RTP。因此，我们检查了客体是否在溶液中与a-CD的包合物中发射RTP。结果发现，α-CD-3-溴喹啉包合物在溶液中产生RTP，在α-CD-3-溴喹啉体系中，存在1：1和2：1的α-CD-3-溴喹啉包合物。合成了碘取代的α-环糊精，研究了溴化-α-环糊精-3-溴喹啉包合物的RTP性质。与α-环糊精相比，溴化-α-CD包合物的RTP降低了约18%。在含有D-葡萄糖的溶液中观察到了β-CD-萘包合物的RTP，其量子产率为0.0022。

At room temperature, phosphorescence from aromatic compounds in solutions cannot be usually observed. However, room-temperature phosphorescence (RTP) from a guest, which is located within a cyclodextrin (CD) inclusion complex, is frequently observed. Until now, beta- and gamma-CDs (derivatives) are known as CD inclusion complexes which emit RTP, except for alpha- CD-6-bromo-2-naphthol and alpha-CD-2-chloronaphthalene inclusion complexes. In the cases of beta- and gamma-CDs, an inclusion complex which contains a single CD molecule emits the RTP of a guest. With alpha-CD, on the other hand, a 2 : 1 a-CD-guest inclusion complex alone emits the RTP.Thus, we examined whether guests emit RTP within inclusion complexes with a-CD in solutions. As a result, we found that alpha-CD-3-bromoquinoline inclusion complex emit the RTP in solution, In the system of alpha-CD-3-bromoquinoline, a 1 : 1 and 2 : 1 alpha-CD-3-bromoquinoline inclusion complexes are confirmed. The formation constants for the inclusion complexes were determined.Iodine-substituted alpha-CD was synthesized to investigate the properties of the RTP of the brominated-alpha-CD-3-bromoquinoline inclusion complex. The RTP of brominated-alpha-CD inclusion complex is reduced about 18% compared to alpha-cyclodextrin. The RTP from beta-CD-naphthalene inclusion complex was observed in solution containing D-glucose ; the RTP quantum yield was evaluated to be 0.0022.