Optical and Photophysical Properties of Light-Harvesting Phenylacetylene Monodendrons Based on Unsymmetrical Branching

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• 作者：Joseph S. Melinger ; Yongchun Pan ; Valeria D. Kleiman ; Zhonghua Peng ; Benjamin L. Davis ; Dale McMorrow ; and Meng Lu
• 刊名：Journal of the American Chemical Society
• 出版年：2002
• 出版时间：October 9, 2002
• 年：2002
• 卷：124
• 期：40
• 页码：12002 - 12012
• 全文大小：267K
• 年卷期：v.124,no.40(October 9, 2002)
• ISSN：1520-5126

文摘

The optical and photophysical properties of phenylacetylene dendritic macromolecules basedon unsymmetrical branching are investigated using steady-state and time-dependent spectroscopy.Monodendrons, up to the fourth generation, are characterized with and without a fluorescent perylene trapat the core. The higher generation monodendrons without the perylene trap exhibit high molar extinctioncoefficients (>10⁵ M^-1 cm^-1) and high fluorescence quantum yields (65-81%). When a perylene trap isplaced at the core, then the monodendrons typically exhibit high energy transfer quantum yields (~90%),as well as subpicosecond time scale excited-state dynamics, as evidenced by ultrafast pump-probemeasurements. The photophysical properties of the unsymmetrical monodendrons are compared to thoseof phenylacetylene monodendrons with symmetrical branching, which have been described recently. Thehigh fluorescence quantum yields and large energy transfer quantum efficiencies exhibited by theunsymmetrical monodendrons suggest they have potential for applications in molecular-based photonicsdevices.