Choosing sides

unusual ultrafast charge transfer pathways in an asymmetric electron-accepting cyclophane that binds an electron donor

Jiawang Zhou, Yilei Wu, Indranil Roy, Avik Samanta, J. Fraser Stoddart, Ryan M. Young, Michael R Wasielewski

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Constructing functional molecular systems for solar energy conversion and quantum information science requires a fundamental understanding of electron transfer in donor-bridge-acceptor (D-B-A) systems as well as competitive reaction pathways in acceptor-donor-acceptor (A-D-A) and acceptor-donor-acceptor′ (A-D-A′) systems. Herein we present a supramolecular complex comprising a tetracationic cyclophane having both phenyl-extended viologen (ExV 2+ ) and dipyridylthiazolothiazole (TTz 2+ ) electron acceptors doubly-linked by means of two p-xylylene linkers (TTzExVBox 4+ ), which readily incorporates a perylene (Per) guest in its cavity (Per ⊂ TTzExVBox 4+ ) to establish an A-D-A′ system, in which the ExV 2+ and TTz 2+ units serve as competing electron acceptors with different reduction potentials. Photoexcitation of the Per guest yields both TTz + -Per + -ExV 2+ and TTz 2+ -Per + -ExV + in <1 ps, while back electron transfer in TTz 2+ -Per + -ExV + proceeds via the unusual sequence TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ → TTz 2+ -Per-ExV 2+ . In addition, selective chemical reduction of TTz 2+ gives Per ⊂ TTzExVBox 3+ turning the complex into a D-B-A system in which photoexcitation of TTz + results in the reaction sequence 2 *TTz + -Per-ExV 2+ → TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ . Both reactions TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ and TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ occur with a (16 ± 1 ps) −1 rate constant irrespective of whether the bridge molecule is Per + or Per. These results are explained using the superexchange mechanism in which the ionic states of the perylene guest serve as virtual states in each case and demonstrate a novel supramolecular platform for studying the effects of bridge energetics within D-B-A systems.

Original languageEnglish
Pages (from-to)4282-4292
Number of pages11
JournalChemical Science
Volume10
Issue number15
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

Perylene
Charge transfer
Electrons
Photoexcitation
Viologens

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Choosing sides : unusual ultrafast charge transfer pathways in an asymmetric electron-accepting cyclophane that binds an electron donor. / Zhou, Jiawang; Wu, Yilei; Roy, Indranil; Samanta, Avik; Stoddart, J. Fraser; Young, Ryan M.; Wasielewski, Michael R.

In: Chemical Science, Vol. 10, No. 15, 01.01.2019, p. 4282-4292.

Research output: Contribution to journalArticle

Zhou, Jiawang ; Wu, Yilei ; Roy, Indranil ; Samanta, Avik ; Stoddart, J. Fraser ; Young, Ryan M. ; Wasielewski, Michael R. / Choosing sides : unusual ultrafast charge transfer pathways in an asymmetric electron-accepting cyclophane that binds an electron donor. In: Chemical Science. 2019 ; Vol. 10, No. 15. pp. 4282-4292.
@article{2e512f544ea847da8ff4cd3fef605594,
title = "Choosing sides: unusual ultrafast charge transfer pathways in an asymmetric electron-accepting cyclophane that binds an electron donor",
abstract = "Constructing functional molecular systems for solar energy conversion and quantum information science requires a fundamental understanding of electron transfer in donor-bridge-acceptor (D-B-A) systems as well as competitive reaction pathways in acceptor-donor-acceptor (A-D-A) and acceptor-donor-acceptor′ (A-D-A′) systems. Herein we present a supramolecular complex comprising a tetracationic cyclophane having both phenyl-extended viologen (ExV 2+ ) and dipyridylthiazolothiazole (TTz 2+ ) electron acceptors doubly-linked by means of two p-xylylene linkers (TTzExVBox 4+ ), which readily incorporates a perylene (Per) guest in its cavity (Per ⊂ TTzExVBox 4+ ) to establish an A-D-A′ system, in which the ExV 2+ and TTz 2+ units serve as competing electron acceptors with different reduction potentials. Photoexcitation of the Per guest yields both TTz + -Per + -ExV 2+ and TTz 2+ -Per + -ExV + in <1 ps, while back electron transfer in TTz 2+ -Per + -ExV + proceeds via the unusual sequence TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ → TTz 2+ -Per-ExV 2+ . In addition, selective chemical reduction of TTz 2+ gives Per ⊂ TTzExVBox 3+ turning the complex into a D-B-A system in which photoexcitation of TTz + results in the reaction sequence 2 *TTz + -Per-ExV 2+ → TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ . Both reactions TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ and TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ occur with a (16 ± 1 ps) −1 rate constant irrespective of whether the bridge molecule is Per + or Per. These results are explained using the superexchange mechanism in which the ionic states of the perylene guest serve as virtual states in each case and demonstrate a novel supramolecular platform for studying the effects of bridge energetics within D-B-A systems.",
author = "Jiawang Zhou and Yilei Wu and Indranil Roy and Avik Samanta and Stoddart, {J. Fraser} and Young, {Ryan M.} and Wasielewski, {Michael R}",
year = "2019",
month = "1",
day = "1",
doi = "10.1039/C8SC05514A",
language = "English",
volume = "10",
pages = "4282--4292",
journal = "Chemical Science",
issn = "2041-6520",
publisher = "Royal Society of Chemistry",
number = "15",

}

TY - JOUR

T1 - Choosing sides

T2 - unusual ultrafast charge transfer pathways in an asymmetric electron-accepting cyclophane that binds an electron donor

AU - Zhou, Jiawang

AU - Wu, Yilei

AU - Roy, Indranil

AU - Samanta, Avik

AU - Stoddart, J. Fraser

AU - Young, Ryan M.

AU - Wasielewski, Michael R

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Constructing functional molecular systems for solar energy conversion and quantum information science requires a fundamental understanding of electron transfer in donor-bridge-acceptor (D-B-A) systems as well as competitive reaction pathways in acceptor-donor-acceptor (A-D-A) and acceptor-donor-acceptor′ (A-D-A′) systems. Herein we present a supramolecular complex comprising a tetracationic cyclophane having both phenyl-extended viologen (ExV 2+ ) and dipyridylthiazolothiazole (TTz 2+ ) electron acceptors doubly-linked by means of two p-xylylene linkers (TTzExVBox 4+ ), which readily incorporates a perylene (Per) guest in its cavity (Per ⊂ TTzExVBox 4+ ) to establish an A-D-A′ system, in which the ExV 2+ and TTz 2+ units serve as competing electron acceptors with different reduction potentials. Photoexcitation of the Per guest yields both TTz + -Per + -ExV 2+ and TTz 2+ -Per + -ExV + in <1 ps, while back electron transfer in TTz 2+ -Per + -ExV + proceeds via the unusual sequence TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ → TTz 2+ -Per-ExV 2+ . In addition, selective chemical reduction of TTz 2+ gives Per ⊂ TTzExVBox 3+ turning the complex into a D-B-A system in which photoexcitation of TTz + results in the reaction sequence 2 *TTz + -Per-ExV 2+ → TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ . Both reactions TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ and TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ occur with a (16 ± 1 ps) −1 rate constant irrespective of whether the bridge molecule is Per + or Per. These results are explained using the superexchange mechanism in which the ionic states of the perylene guest serve as virtual states in each case and demonstrate a novel supramolecular platform for studying the effects of bridge energetics within D-B-A systems.

AB - Constructing functional molecular systems for solar energy conversion and quantum information science requires a fundamental understanding of electron transfer in donor-bridge-acceptor (D-B-A) systems as well as competitive reaction pathways in acceptor-donor-acceptor (A-D-A) and acceptor-donor-acceptor′ (A-D-A′) systems. Herein we present a supramolecular complex comprising a tetracationic cyclophane having both phenyl-extended viologen (ExV 2+ ) and dipyridylthiazolothiazole (TTz 2+ ) electron acceptors doubly-linked by means of two p-xylylene linkers (TTzExVBox 4+ ), which readily incorporates a perylene (Per) guest in its cavity (Per ⊂ TTzExVBox 4+ ) to establish an A-D-A′ system, in which the ExV 2+ and TTz 2+ units serve as competing electron acceptors with different reduction potentials. Photoexcitation of the Per guest yields both TTz + -Per + -ExV 2+ and TTz 2+ -Per + -ExV + in <1 ps, while back electron transfer in TTz 2+ -Per + -ExV + proceeds via the unusual sequence TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ → TTz 2+ -Per-ExV 2+ . In addition, selective chemical reduction of TTz 2+ gives Per ⊂ TTzExVBox 3+ turning the complex into a D-B-A system in which photoexcitation of TTz + results in the reaction sequence 2 *TTz + -Per-ExV 2+ → TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ . Both reactions TTz 2+ -Per + -ExV + → TTz + -Per + -ExV 2+ and TTz 2+ -Per-ExV + → TTz + -Per-ExV 2+ occur with a (16 ± 1 ps) −1 rate constant irrespective of whether the bridge molecule is Per + or Per. These results are explained using the superexchange mechanism in which the ionic states of the perylene guest serve as virtual states in each case and demonstrate a novel supramolecular platform for studying the effects of bridge energetics within D-B-A systems.

UR - http://www.scopus.com/inward/record.url?scp=85064177256&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064177256&partnerID=8YFLogxK

U2 - 10.1039/C8SC05514A

DO - 10.1039/C8SC05514A

M3 - Article

VL - 10

SP - 4282

EP - 4292

JO - Chemical Science

JF - Chemical Science

SN - 2041-6520

IS - 15

ER -