Zhang Zhi-Yuan, Chen Yong, Liu Yu
College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China.
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300072, China.
Angew Chem Int Ed Engl. 2019 Apr 23;58(18):6028-6032. doi: 10.1002/anie.201901882. Epub 2019 Mar 26.
Efficient emission of purely organic room-temperature phosphorescence (RTP) is of great significant for potential application in optoelectronics and photobiology. Herein, we report an uncommon phosphorescent effect of organic single molecule enhanced by resulting supramolecular assembly of host-guest complexation. The chromophore bromophenyl-methyl-pyridinium (PY) with different counterions as guests display various phosphorescence quantum yields from 0.4 % to 24.1 %. Single crystal X-ray diffraction results indicate that the chromophore with iodide counterion (PYI) exhibits the highest efficiency maybe due to the halogen-bond interactions. Significantly, the nanosupramolecular assembly of PY chloride complexation with the cucurbit[6]uril gives a greatly enhanced phosphorescent quantum yield up to 81.2 % in ambient. Such great enhancement is because of the strict encapsulation of cucurbit[6]uril, which prevents the nonradiative relaxation and promotes intersystem crossing (ISC). This supramolecular assembly concept with counterions effect provides a novel approach for the improvement of RTP.
高效发射纯有机室温磷光（RTP）对于光电子学和光生物学的潜在应用具有重要意义。在此，我们报道了一种不寻常的有机单分子磷光效应，该效应通过主客体络合形成的超分子组装得到增强。以不同抗衡离子作为客体的发色团溴苯基 - 甲基 - 吡啶鎓（PY）表现出从0.4％到24.1％的各种磷光量子产率。单晶X射线衍射结果表明，带有碘离子抗衡离子的发色团（PYI）表现出最高的效率，这可能归因于卤素键相互作用。值得注意的是，氯化PY与葫芦[6]脲络合形成的纳米超分子组装体在环境中给出了高达81.2％的大大增强的磷光量子产率。如此大的增强是由于葫芦[6]脲的严格封装，它防止了非辐射弛豫并促进了系间窜越（ISC）。这种具有抗衡离子效应的超分子组装概念为改善RTP提供了一种新方法。
