Electron and energy transfer in a porphyrin–oxoporphyrinogen–fullerene triad, ZnP–OxP–C60. Issue 25 (22nd June 2020)

• Record Type: Journal Article
• Authors: Chahal, Mandeep K.; Gobeze, Habtom B.; Webre, Whitney A.; Karr, Paul A.; Payne, Daniel T.; Ariga, Katsuhiko; D'Souza, Francis; Hill, Jonathan P.
• Is Part Of: Physical chemistry chemical physics. Volume 22:Issue 25(2020)
• Page Start: 14356
• Page End: 14363
• Publication Date: 2020-06-22
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d0cp02696d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Competitive energy and electron transfer in a newly synthesized supramolecular triad composed of zinc porphyrin, oxoporphyrinogen and C60 has been demonstrated using ultrafast pump–probe spectroscopy. Abstract : A multichromophoric triad, ZnP–OxP–C60 containing porphyrin (ZnTPP hereafter ZnP ), oxoporphyrinogen (OxP ) and fullerene (C60 ) has been synthesized to probe the intramolecular dynamics of its electron and energy transfer in relation to the presence of the closely linked electron deficient OxP–C60 'special pair', constructed as a mimic of the naturally occurring photosynthetic antenna-reaction center. The DFT optimized structure of the triad reveals the relative spatial remoteness of the ZnP entity with proximal OxP /C60 entities. Free-energetics of different energy and electron transfer events were estimated using spectral, computational and electrochemical studies, according to the Rehm–Weller approach. Femtosecond transient absorption spectral studies revealed energy transfer from 1 ZnP* to OxP to yield ZnP– 1 OxP*–C60, and electron transfer to yield ZnP˙ + –OxP–C60 ˙ − and/or ZnP–OxP˙ + –C60 ˙ − charge seperated states. That is, the ZnP entity in the triad operates as both antenna and electron donor to generate relatively long-lived charge separated states thus mimicking the early photoevents of natural photosynthesis.