Synthesis and photophysical properties of light-harvesting arrays comprised of a porphyrin bearing multiple perylene-monoimide accessory pigments
| Autor: | David F. Bocian, Jennifer K. Schwartz, Robert S. Loewe, Christine Kirmaier, Kin-ya Tomizaki, Dewey Holten, Jennifer L. Retsek, Jonathan S. Lindsey |
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| Rok vydání: | 2002 |
| Předmět: |
Models
Molecular Magnetic Resonance Spectroscopy Light Metalloporphyrins Photochemistry Energy transfer Fluorescence spectrometry Molecular Conformation Chemical synthesis chemistry.chemical_compound Imide Perylene Chromatography High Pressure Liquid Molecular Structure Spectrophotometry Atomic Organic Chemistry Temperature Pigments Biological Porphyrin Zinc porphyrin Zinc chemistry Energy Transfer Indicators and Reagents Accessory pigment |
| Zdroj: | The Journal of organic chemistry. 67(18) |
| ISSN: | 0022-3263 |
| Popis: | We present the synthesis and characterization of new light-harvesting arrays containing two, four, or eight perylene-monoimide accessory pigments attached to a zinc porphyrin. Each perylene is substituted with one or three 4-tert-butylphenoxy substituents. A 4,3'- or 4,2'-diarylethyne linker joins the perylene N-imide position and the porphyrin meso-position, affording divergent or convergent architectures, respectively. The architectures are designed to provide high solubility in organic media and facile perylene-to-porphyrin energy transfer, while avoiding charge-transfer quenching of the excited porphyrin product. For the array containing four perylenes per porphyrin in both nonpolar (toluene) and polar (benzonitrile) media and for the array containing eight perylenes per porphyrin in toluene, the photoexcited perylene-monoimide dye (PMI) decays rapidly ( approximately 3.5 ps) and predominantly (or=90%) by energy transfer to the zinc porphyrin to form the excited zinc porphyrin (Zn), which has excited-state characteristics (lifetime, fluorescence yield) comparable (within approximately 10%) to those of the isolated chromophore. For the array containing eight perylenes in benzonitrile, PMI decays approximately 80% by energy transfer (forming Zn) and approximately 20% by hole transfer (forming PMI- Zn+); Zn subsequently decays approximately 20% by electron transfer (also forming PMI- Zn+) and approximately 80% by the normal routes open to the porphyrin monomer (intersystem crossing, internal conversion, fluorescence). In addition to rapid and efficient perylene-to-porphyrin energy transfer, the broad blue-green to yellow absorption of the perylene dyes complements the blue absorption of the porphyrin, resulting in excellent light harvesting across a significant spectral region. Collectively, the work described herein identifies multiperylene-porphyrin arrays that exhibit suitable photochemical properties for use as motifs in larger light-harvesting systems. |
| Databáze: | OpenAIRE |
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