Distance-Dependent Electron Transfer Kinetics in Axially Connected Silicon Phthalocyanine-Fullerene Conjugates.
Chemphyschem
; 21(20): 2254-2262, 2020 10 16.
Article
em En
| MEDLINE
| ID: mdl-33448590
ABSTRACT
The effect of donor-acceptor distance in controlling the rate of electron transfer in axially linked silicon phthalocyanine-C60 dyads has been investigated. For this, two C60-SiPc-C60 dyads, 1 and 2, varying in their donor-acceptor distance, have been newly synthesized and characterized. In the case of C60-SiPc-C60 1 where the SiPc and C60 are separated by a phenyl spacer, faster electron transfer was observed with kcs equal to 2.7×109â
s-1 in benzonitrile. However, in the case of C60-SiPc-C60 2, where SiPc and C60 are separated by a biphenyl spacer, a slower electron transfer rate constant, kcs=9.1×108â
s-1, was recorded. The addition of an extra phenyl spacer in 2 increased the donor-acceptor distance by â¼4.3â
Å, and consequently, slowed down the electron transfer rate constant by a factor of â¼3.7. The charge separated state lasted over 3â
ns, monitoring time window of our femtosecond transient spectrometer. Complimentary nanosecond transient absorption studies revealed formation of 3SiPc* as the end product and suggested the final lifetime of the charge separated state to be in the 3-20â
ns range. Energy level diagrams established to comprehend these mechanistic details indicated that the comparatively high-energy SiPc.+-C60.- charge separated states (1.57â
eV) populated the low-lying 3SiPc* (1.26â
eV) prior returning to the ground state.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Chemphyschem
Assunto da revista:
BIOFISICA
/
QUIMICA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Espanha
País de publicação:
ALEMANHA
/
ALEMANIA
/
DE
/
DEUSTCHLAND
/
GERMANY