Synthesis and Optical Properties of Pyrrolo[3,2-b]pyrrole-2,5(1H,4H)-dione (iDPP)-Based Molecules

详细信息    查看全文

• 作者：Mindaugas Kirkus ; Stefan Knippenberg ; David Beljonne ; J茅r么me Cornil ; Ren茅 A. J. Janssen ; Stefan C. J. Meskers
• 刊名：The Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：April 4, 2013
• 年：2013
• 卷：117
• 期：13
• 页码：2782-2789
• 全文大小：420K
• 年卷期：v.117,no.13(April 4, 2013)
• ISSN：1520-5215

文摘

We describe the synthesis and photophysical properties of a series of derivatives of pyrrolo[3,2-b]pyrrole-2,5(1H,4H)-dione-3,6-diyl (iDPP) linked to two oligothiophenes of variable length (nT). The iso-DPP-oligothiophenes (iDPPnTs) differ from the common pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-3,6-diyl-oligothiophene analogues (DPPnTs) by a different orientation of the two lactam rings in the bicyclic iDPP unit compared to DPP. In contrast to the highly fluorescent DPPnTs, the new isomeric iDPPnTs exhibit only very weak fluorescence. We demonstrate with the help of quantum-chemical calculations that this can be attributed to a different symmetry of the lowest excited state in iDPPnT (A in C₂ symmetry) compared to DPPnTs (B) and the corresponding loss in oscillator strength of the lowest energy transition. Upon extending the oligothiophene moiety in the iDPPnTs molecules, the charge transfer character of the lowest A excited state becomes more pronounced. This tends to preclude high fluorescence quantum yields even in extended iDPPnTs systems.