Engineering Soluble Diketopyrrolopyrrole Chromophore Stacks from a Series of Pd(II)-Based Ravels** |
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Authors: | Dr. Irene Regeni Rituparno Chowdhury Kai Terlinden Dr. Shinnosuke Horiuchi Dr. Julian J. Holstein Dr. Sascha Feldmann Prof. Dr. Guido H. Clever |
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Affiliation: | 1. Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany;2. Cavendish Laboratory, University of Cambridge, Cambridge, CB30HE UK |
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Abstract: | A strategy to engineer the stacking of diketopyrrolopyrrole (DPP) dyes based on non-statistical metallosupramolecular self-assembly is introduced. For this, the DPP backbone is equipped with nitrogen-based donors that allow for different discrete assemblies to be formed upon the addition of Pd(II), distinguished by the number of π-stacked chromophores. A Pd3L6 three-ring, a heteroleptic Pd2L2L′2 ravel composed of two crossing DPPs (flanked by two carbazoles), and two unprecedented self-penetrated motifs (a Pd2L3 triple and a Pd2L4 quadruple stack), were obtained and systematically investigated. With increasing counts of stacked chromophores, UV/Vis absorptions red-shift and emission intensities decrease, except for compound Pd2L2L′2, which stands out with an exceptional photoluminescence quantum yield of 51 %. This is extraordinary for open-shell metal containing assemblies and explainable by an intra-assembly FRET process. The modular design and synthesis of soluble multi-chromophore building blocks offers the potential for the preparation of nanodevices and materials with applications in sensing, photo-redox catalysis and optics. |
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Keywords: | Chromophores Coordination Cages Energy Transfer Self-Assembly Supramolecular Chemistry |
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