Strongly Coupled Oxasmaragdyrin-BF₂ Chelated Dipyrrin Dyads: Syntheses, X-ray Structure, Ground- and Excited-State Charge-Transfer Interactions

详细信息    查看全文

• 作者：Habtom B. Gobeze ; Sunit Kumar ; Prof. Dr. Francis D'Souza and Prof. Dr. Mangalampalli Ravikanth
• 刊名：Chemistry - A European Journal
• 出版年：2017
• 出版时间：January 31, 2017
• 年：2017
• 卷：23
• 期：7
• 页码：1546-1556
• 全文大小：3938K
• ISSN：1521-3765

文摘

Oxasmaragdyrin (osm), a 22-π electron aromatic macrocycle containing four pyrroles and a furan ring connected by three methine bridges and two direct bonds is shown to be an excellent electron donor–sensitizer exhibiting adequate spectral and redox properties. Further, this novel heterocyclic macromolecule has been utilized in building donor–acceptor systems involving BF₂-chelated dipyrromethenes (BODIPYs). The osm–BODIPY dyads were fully characterized by optical, electrochemical, computational, and X-ray diffraction studies. Due to close proximity and electronic structure of the donor and acceptor entities, strong intramolecular charge-transfer interactions in these dyads was witnessed and was supported by computational studies. Solvent-polarity-dependent rapid charge separation and charge recombination in these dyads is witnessed from photochemical studies involving time-resolved emission and femtosecond transient absorption studies. The present studies bring out the importance of oxasmaragdyrin as an electron donor in light-energy-harvesting artificial photosynthesis model systems.