Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea).
Angew Chem Int Ed Engl. 2014 Jul 1;53(27):6925-8. doi: 10.1002/anie.201400835. Epub 2014 May 14.
An artificial light-harvesting multiporphyrin dendrimer (8P(Zn)P(FB)) composed of a focal freebase porphyrin (P(FB)) with eight zinc(II) porphyrin (P(Zn)) wings exhibited unique photophysical property switching in response to specific guest molecule binding. UV/Vis titration studies indicated stable 1:2 host-guest complex formation between 8P(Zn)P(FB) and meso-tetrakis(4-pyridyl)-porphyrin (TPyP) for which the first and second association constants were estimated to be >10(8) M(-1) and 3.0×10(7) M(-1), respectively. 8P(Zn)P(FB) originally shows 94% energy transfer efficiency from P(Zn) to the focal P(FB). By the formation of the host-guest complex (8P(Zn)P(FB)⋅2TPyP) the emission intensity of 8P(Zn)P(FB) is significantly decreased, and an ultrafast charge separation state is generated. The energy transfer process from P(Zn) wings to the P(FB) core in 8P(Zn)P(FB) is almost entirely switched to an electron transfer process by the formation of 8P(Zn)P(FB)⋅2TPyP.
由一个焦点自由碱卟啉（P(FB)）与八个锌(II)卟啉（P(Zn)）翅膀组成的人工光捕获多卟啉树状大分子（8P(Zn)P(FB)），表现出独特的光物理性质切换，以响应特定的客体分子结合。UV/Vis 滴定研究表明，8P(Zn)P(FB)和间四(4-吡啶基)-卟啉（TPyP）之间存在稳定的 1:2 主客体配合物形成，其第一和第二结合常数分别估计为>10(8) M(-1)和 3.0×10(7) M(-1)。8P(Zn)P(FB)最初显示出 94%的能量从 P(Zn)转移到焦点 P(FB)的效率。通过形成主体-客体配合物（8P(Zn)P(FB)·2TPyP），8P(Zn)P(FB)的发射强度显著降低，并产生超快电荷分离态。在 8P(Zn)P(FB)中，从 P(Zn)翅膀到 P(FB)核心的能量转移过程通过形成 8P(Zn)P(FB)·2TPyP，几乎完全切换为电子转移过程。
