title: Strongly Coupled Oxasmaragdyrin-BF2Chelated Dipyrrin Dyads: Syntheses, X-ray Structure, Ground- and Excited-State Charge-Transfer Interactions.
abstract: 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.
authors: Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX, 76203-5017, USA.
authors: Habtom B
authors: HB
authors: Gobeze
authors: Indian Institute of Technology, Powa, Mumbai, 400076, India.
authors: Sunit
authors: S
authors: Kumar
authors: Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX, 76203-5017, USA.
authors: Francis
authors: http://orcid.org/0000-0003-3815-8949
authors: F
authors: D'Souza
authors: Indian Institute of Technology, Powa, Mumbai, 400076, India.
authors: Mangalampalli
authors: M
authors: Ravikanth
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D055664:Electrochemical Techniques; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D047028:Macrocyclic Compounds; D011758:Pyrroles; D012997:Solvents; C579460:boron difluoride; C000626379:oxasmaragdyrin-BF2
keywords: BODIPY; boron; charge transfer; donor-acceptor systems; macrocycles; oxasmaragdyrin