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Multichromophoric Perylenediimide–Silicon Phthalocyanine–C 60 System as an Artificial Photosynthetic Analogue
Author(s) -
MartínGomis Luis,
PeraltaRuiz Francisco,
Thomas Michael B.,
FernándezLázaro Fernando,
D'Souza Francis,
SastreSantos Ángela
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201603741
Subject(s) - triad (sociology) , photochemistry , acceptor , electron transfer , electron donor , electron acceptor , chemistry , ultrafast laser spectroscopy , photoinduced electron transfer , materials science , spectroscopy , organic chemistry , psychology , physics , quantum mechanics , psychoanalysis , condensed matter physics , catalysis
Sequential photoinduced energy transfer followed by electron transfer and the formation of charge‐separated states, which are primary events of natural photosynthesis, have been demonstrated in a newly synthesized multichromophoric covalently linked triad, PDI‐SiPc‐C 60 . The triad comprises a perylenediimide (PDI), which primarily fulfils antenna and electron‐acceptor functionalities, silicon phthalocyanine (SiPc) as an electron donor, and fulleropyrrolidine (C 60 ) as a second electron acceptor. The multi‐step convergent synthetic procedure developed here produced good yields of the triad and control dyads, PDI‐SiPc and SiPc‐C 60 . The structures and geometries of the newly synthesized donor–acceptor systems have been established from spectral, computational, and electrochemical studies with reference to appropriate control compounds. Ultrafast energy transfer from 1 PDI* to SiPc in the case of PDI‐SiPc and PDI‐SiPc‐C 60 was witnessed. An energy‐level diagram established from spectral and electrochemical data suggested the formation of two types of charge‐separated states, that is, PDI‐SiPc .+ ‐C 60 .− and PDI .− ‐SiPc .+ ‐C 60 from the 1 SiPc* in the triad, with generation of the latter being energetically more favorable. However, photochemical studies involving femtosecond transient spectroscopy revealed the formation of PDI‐SiPc .+ ‐C 60 .− as a major charge‐separated product. This observation may be rationalized in terms of the closer spatial proximity to SiPc of C 60 compared to PDI in the triad. The charge‐separated state persisted for a few nanoseconds prior to populating the 3 SiPc* state during charge recombination.