Photoinduced electron transfer within a zinc porphyrin-cyclobis(paraquat-p-phenylene) donor-acceptor dyad

Maher Fathalla, Jonathan C. Barnes, Ryan M. Young, Karel J. Hartlieb, Scott M. Dyar, Samuel W. Eaton, Amy A. Sarjeant, Dick T Co, Michael R Wasielewski, J. Fraser Stoddart

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Understanding the mechanism of efficient photoinduced electron-transfer processes is essential for developing molecular systems for artificial photosynthesis. Towards this goal, we describe the synthesis of a donor-acceptor dyad comprising a zinc porphyrin donor and a tetracationic cyclobis(paraquat-p-phenylene) (CBPQT(4+) ) acceptor. The X-ray crystal structure of the dyad reveals the formation of a dimeric motif through the intermolecular coordination between the triazole nitrogen and the central Zn metal of two adjacent units of the dyad. Photoinduced electron transfer within the dyad in MeCN was investigated by femtosecond and nanosecond transient absorption spectroscopy, as well as by transient EPR spectroscopy. Photoexcitation of the dyad produced a weakly coupled ZnP(+.) -CBPQT(3+.) spin-correlated radical-ion pair having a τ=146 ns lifetime and a spin-spin exchange interaction of only 0.23 mT. The long radical-ion-pair lifetime results from weak donor-acceptor electronic coupling as a consequence of having nine bonds between the donor and the acceptor, and the reduction in reorganization energy for electron transfer caused by charge dispersal over both paraquat units within CBPQT(3+.) .

Original languageEnglish
Pages (from-to)14690-14697
Number of pages8
JournalChemistry - A European Journal
Volume20
Issue number45
DOIs
Publication statusPublished - Nov 3 2014

Fingerprint

Paraquat
Porphyrins
Zinc
Electrons
Spectrum Analysis
Ions
Triazoles
Photosynthesis
Photoexcitation
Energy Transfer
Exchange interactions
Absorption spectroscopy
Paramagnetic resonance
Nitrogen
Crystal structure
Metals
X-Rays
Spectroscopy
X rays
zinc hematoporphyrin

Keywords

  • donor-acceptor systems
  • electron transfer
  • porphyrinoids
  • transient absorption spectroscopy

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Fathalla, M., Barnes, J. C., Young, R. M., Hartlieb, K. J., Dyar, S. M., Eaton, S. W., ... Stoddart, J. F. (2014). Photoinduced electron transfer within a zinc porphyrin-cyclobis(paraquat-p-phenylene) donor-acceptor dyad. Chemistry - A European Journal, 20(45), 14690-14697. https://doi.org/10.1002/chem.201403744

Photoinduced electron transfer within a zinc porphyrin-cyclobis(paraquat-p-phenylene) donor-acceptor dyad. / Fathalla, Maher; Barnes, Jonathan C.; Young, Ryan M.; Hartlieb, Karel J.; Dyar, Scott M.; Eaton, Samuel W.; Sarjeant, Amy A.; Co, Dick T; Wasielewski, Michael R; Stoddart, J. Fraser.

In: Chemistry - A European Journal, Vol. 20, No. 45, 03.11.2014, p. 14690-14697.

Research output: Contribution to journalArticle

Fathalla, M, Barnes, JC, Young, RM, Hartlieb, KJ, Dyar, SM, Eaton, SW, Sarjeant, AA, Co, DT, Wasielewski, MR & Stoddart, JF 2014, 'Photoinduced electron transfer within a zinc porphyrin-cyclobis(paraquat-p-phenylene) donor-acceptor dyad', Chemistry - A European Journal, vol. 20, no. 45, pp. 14690-14697. https://doi.org/10.1002/chem.201403744
Fathalla, Maher ; Barnes, Jonathan C. ; Young, Ryan M. ; Hartlieb, Karel J. ; Dyar, Scott M. ; Eaton, Samuel W. ; Sarjeant, Amy A. ; Co, Dick T ; Wasielewski, Michael R ; Stoddart, J. Fraser. / Photoinduced electron transfer within a zinc porphyrin-cyclobis(paraquat-p-phenylene) donor-acceptor dyad. In: Chemistry - A European Journal. 2014 ; Vol. 20, No. 45. pp. 14690-14697.
@article{6a9b028140ad47078717f548966ffa71,
title = "Photoinduced electron transfer within a zinc porphyrin-cyclobis(paraquat-p-phenylene) donor-acceptor dyad",
abstract = "Understanding the mechanism of efficient photoinduced electron-transfer processes is essential for developing molecular systems for artificial photosynthesis. Towards this goal, we describe the synthesis of a donor-acceptor dyad comprising a zinc porphyrin donor and a tetracationic cyclobis(paraquat-p-phenylene) (CBPQT(4+) ) acceptor. The X-ray crystal structure of the dyad reveals the formation of a dimeric motif through the intermolecular coordination between the triazole nitrogen and the central Zn metal of two adjacent units of the dyad. Photoinduced electron transfer within the dyad in MeCN was investigated by femtosecond and nanosecond transient absorption spectroscopy, as well as by transient EPR spectroscopy. Photoexcitation of the dyad produced a weakly coupled ZnP(+.) -CBPQT(3+.) spin-correlated radical-ion pair having a τ=146 ns lifetime and a spin-spin exchange interaction of only 0.23 mT. The long radical-ion-pair lifetime results from weak donor-acceptor electronic coupling as a consequence of having nine bonds between the donor and the acceptor, and the reduction in reorganization energy for electron transfer caused by charge dispersal over both paraquat units within CBPQT(3+.) .",
keywords = "donor-acceptor systems, electron transfer, porphyrinoids, transient absorption spectroscopy",
author = "Maher Fathalla and Barnes, {Jonathan C.} and Young, {Ryan M.} and Hartlieb, {Karel J.} and Dyar, {Scott M.} and Eaton, {Samuel W.} and Sarjeant, {Amy A.} and Co, {Dick T} and Wasielewski, {Michael R} and Stoddart, {J. Fraser}",
year = "2014",
month = "11",
day = "3",
doi = "10.1002/chem.201403744",
language = "English",
volume = "20",
pages = "14690--14697",
journal = "Chemistry - A European Journal",
issn = "0947-6539",
publisher = "Wiley-VCH Verlag",
number = "45",

}

TY - JOUR

T1 - Photoinduced electron transfer within a zinc porphyrin-cyclobis(paraquat-p-phenylene) donor-acceptor dyad

AU - Fathalla, Maher

AU - Barnes, Jonathan C.

AU - Young, Ryan M.

AU - Hartlieb, Karel J.

AU - Dyar, Scott M.

AU - Eaton, Samuel W.

AU - Sarjeant, Amy A.

AU - Co, Dick T

AU - Wasielewski, Michael R

AU - Stoddart, J. Fraser

PY - 2014/11/3

Y1 - 2014/11/3

N2 - Understanding the mechanism of efficient photoinduced electron-transfer processes is essential for developing molecular systems for artificial photosynthesis. Towards this goal, we describe the synthesis of a donor-acceptor dyad comprising a zinc porphyrin donor and a tetracationic cyclobis(paraquat-p-phenylene) (CBPQT(4+) ) acceptor. The X-ray crystal structure of the dyad reveals the formation of a dimeric motif through the intermolecular coordination between the triazole nitrogen and the central Zn metal of two adjacent units of the dyad. Photoinduced electron transfer within the dyad in MeCN was investigated by femtosecond and nanosecond transient absorption spectroscopy, as well as by transient EPR spectroscopy. Photoexcitation of the dyad produced a weakly coupled ZnP(+.) -CBPQT(3+.) spin-correlated radical-ion pair having a τ=146 ns lifetime and a spin-spin exchange interaction of only 0.23 mT. The long radical-ion-pair lifetime results from weak donor-acceptor electronic coupling as a consequence of having nine bonds between the donor and the acceptor, and the reduction in reorganization energy for electron transfer caused by charge dispersal over both paraquat units within CBPQT(3+.) .

AB - Understanding the mechanism of efficient photoinduced electron-transfer processes is essential for developing molecular systems for artificial photosynthesis. Towards this goal, we describe the synthesis of a donor-acceptor dyad comprising a zinc porphyrin donor and a tetracationic cyclobis(paraquat-p-phenylene) (CBPQT(4+) ) acceptor. The X-ray crystal structure of the dyad reveals the formation of a dimeric motif through the intermolecular coordination between the triazole nitrogen and the central Zn metal of two adjacent units of the dyad. Photoinduced electron transfer within the dyad in MeCN was investigated by femtosecond and nanosecond transient absorption spectroscopy, as well as by transient EPR spectroscopy. Photoexcitation of the dyad produced a weakly coupled ZnP(+.) -CBPQT(3+.) spin-correlated radical-ion pair having a τ=146 ns lifetime and a spin-spin exchange interaction of only 0.23 mT. The long radical-ion-pair lifetime results from weak donor-acceptor electronic coupling as a consequence of having nine bonds between the donor and the acceptor, and the reduction in reorganization energy for electron transfer caused by charge dispersal over both paraquat units within CBPQT(3+.) .

KW - donor-acceptor systems

KW - electron transfer

KW - porphyrinoids

KW - transient absorption spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=84934287863&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84934287863&partnerID=8YFLogxK

U2 - 10.1002/chem.201403744

DO - 10.1002/chem.201403744

M3 - Article

VL - 20

SP - 14690

EP - 14697

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

SN - 0947-6539

IS - 45

ER -