Guest‐Induced Photophysical Property Switching of Artificial Light‐Harvesting Dendrimers1. (14th May 2014)

• Record Type: Journal Article
• Authors: Jeong, Young‐Hwan; Son, Minjung; Yoon, Hongsik; Kim, Pyosang; Lee, Do‐Hyung; Kim, Dongho; Jang, Woo‐Dong
• Is Part Of: Angewandte Chemie. Volume 126:Number 27(2014)
• Page Start: 7045
• Page End: 7048
• Publication Date: 2014-05-14
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201400835
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>An artificial light‐harvesting multiporphyrin dendrimer (<bold>8P<sub>Zn</sub>P<sub>FB</sub></bold>) composed of a focal freebase porphyrin (<bold>P<sub>FB</sub></bold>) with eight zinc(II) porphyrin (<bold>P<sub>Zn</sub></bold>) 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 <bold>8P<sub>Zn</sub>P<sub>FB</sub></bold> and <italic>meso</italic>‐tetrakis(4‐pyridyl)‐porphyrin (<bold>TPyP</bold>) for which the first and second association constants were estimated to be >10<sup>8</sup> <sc>M</sc><sup>−1</sup> and 3.0×10<sup>7</sup> <sc>M</sc><sup>−1</sup>, respectively. <bold>8P<sub>Zn</sub>P<sub>FB</sub></bold> originally shows 94 % energy transfer efficiency from <bold>P<sub>Zn</sub></bold> to the focal <bold>P<sub>FB</sub></bold>. By the formation of the host–guest complex (<bold>8P<sub>Zn</sub>P<sub>FB</sub>⋅</bold>2<bold>TPyP</bold>) the emission intensity of <bold>8P<sub>Zn</sub>P<sub>FB</sub></bold> is significantly decreased, and an ultrafast charge separation state is generated. The energy transfer process from <bold>P<sub>Zn</sub></bold> wings to the <bold>P<sub>FB</sub></bold> core in <bold>8P<sub>Zn</sub>P<sub>FB</sub></bold> is almost entirely switched to an electron transfer process by the formation of <bold>8P<sub>Zn</sub>P<sub>FB</sub>⋅</bold>2<bold>TPyP</bold>.</p> </abstract>