Breaking the semi-quinoid structure: Spin-switching from strongly coupled singlet to polarized triplet state

Prince Ravat; Yoshio Teki; Yoshikazu Ito; Elena Gorelik; Martin Baumgarten

doi:10.1002/chem.201403338

Breaking the semi-quinoid structure: Spin-switching from strongly coupled singlet to polarized triplet state

Prince Ravat, Yoshio Teki, Yoshikazu Ito, Elena Gorelik, Martin Baumgarten

Research output: Contribution to journal › Article › peer-review

13 Citations (Scopus)

Abstract

2,7-TMPNO (4,5,9,10-tetramethoxypyrene-2,7-bis(tert-butylnitroxide)) was found to exist in semi-quinoid form with unprecedented strong intramolecular magnetic exchange interaction of 2J/k_B=1185 K operating over a distance of 10 Å. Structural transformations with the activation energy of ΔE_eq=949 K were observed by varying the temperature, from more quinoid structure at low temperature to more biradicaloid structure at higher temperature. Moreover, this molecule undergoes a transient spin transition from singlet to polarized triplet state upon photoexcitation revealed by TREPR spectroscopy. The spin Hamiltonian parameters were determined to be S=1, g=2.0065, D=-0.0112 cm^-1, and E=-0.0014 cm^-1 by spectral simulation with the hybrid Eigenfield/exact diagonalization method.

Original language	English
Pages (from-to)	12041-12045
Number of pages	5
Journal	Chemistry - A European Journal
Volume	20
Issue number	38
DOIs	https://doi.org/10.1002/chem.201403338
Publication status	Published - 2014 Sept 15

Keywords

EPR spectroscopy
density functional calculations
magnetic exchange interactions
pyrenes
semi-quinoid

ASJC Scopus subject areas

Catalysis
Organic Chemistry

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10.1002/chem.201403338

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@article{de984022c8594f20a997539efe69b5e5,

title = "Breaking the semi-quinoid structure: Spin-switching from strongly coupled singlet to polarized triplet state",

abstract = "2,7-TMPNO (4,5,9,10-tetramethoxypyrene-2,7-bis(tert-butylnitroxide)) was found to exist in semi-quinoid form with unprecedented strong intramolecular magnetic exchange interaction of 2J/kB=1185 K operating over a distance of 10 {\AA}. Structural transformations with the activation energy of ΔEeq=949 K were observed by varying the temperature, from more quinoid structure at low temperature to more biradicaloid structure at higher temperature. Moreover, this molecule undergoes a transient spin transition from singlet to polarized triplet state upon photoexcitation revealed by TREPR spectroscopy. The spin Hamiltonian parameters were determined to be S=1, g=2.0065, D=-0.0112 cm-1, and E=-0.0014 cm-1 by spectral simulation with the hybrid Eigenfield/exact diagonalization method.",

keywords = "EPR spectroscopy, density functional calculations, magnetic exchange interactions, pyrenes, semi-quinoid",

author = "Prince Ravat and Yoshio Teki and Yoshikazu Ito and Elena Gorelik and Martin Baumgarten",

note = "Publisher Copyright: {\textcopyright} 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.",

year = "2014",

month = sep,

day = "15",

doi = "10.1002/chem.201403338",

language = "English",

volume = "20",

pages = "12041--12045",

journal = "Chemistry - A European Journal",

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publisher = "Wiley-VCH Verlag",

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TY - JOUR

T1 - Breaking the semi-quinoid structure

T2 - Spin-switching from strongly coupled singlet to polarized triplet state

AU - Ravat, Prince

AU - Teki, Yoshio

AU - Ito, Yoshikazu

AU - Gorelik, Elena

AU - Baumgarten, Martin

PY - 2014/9/15

Y1 - 2014/9/15

N2 - 2,7-TMPNO (4,5,9,10-tetramethoxypyrene-2,7-bis(tert-butylnitroxide)) was found to exist in semi-quinoid form with unprecedented strong intramolecular magnetic exchange interaction of 2J/kB=1185 K operating over a distance of 10 Å. Structural transformations with the activation energy of ΔEeq=949 K were observed by varying the temperature, from more quinoid structure at low temperature to more biradicaloid structure at higher temperature. Moreover, this molecule undergoes a transient spin transition from singlet to polarized triplet state upon photoexcitation revealed by TREPR spectroscopy. The spin Hamiltonian parameters were determined to be S=1, g=2.0065, D=-0.0112 cm-1, and E=-0.0014 cm-1 by spectral simulation with the hybrid Eigenfield/exact diagonalization method.

AB - 2,7-TMPNO (4,5,9,10-tetramethoxypyrene-2,7-bis(tert-butylnitroxide)) was found to exist in semi-quinoid form with unprecedented strong intramolecular magnetic exchange interaction of 2J/kB=1185 K operating over a distance of 10 Å. Structural transformations with the activation energy of ΔEeq=949 K were observed by varying the temperature, from more quinoid structure at low temperature to more biradicaloid structure at higher temperature. Moreover, this molecule undergoes a transient spin transition from singlet to polarized triplet state upon photoexcitation revealed by TREPR spectroscopy. The spin Hamiltonian parameters were determined to be S=1, g=2.0065, D=-0.0112 cm-1, and E=-0.0014 cm-1 by spectral simulation with the hybrid Eigenfield/exact diagonalization method.

KW - EPR spectroscopy

KW - density functional calculations

KW - magnetic exchange interactions

KW - pyrenes

KW - semi-quinoid

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U2 - 10.1002/chem.201403338

DO - 10.1002/chem.201403338

M3 - Article

AN - SCOPUS:84916607671

SN - 0947-6539

VL - 20

SP - 12041

EP - 12045

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 38

ER -

Breaking the semi-quinoid structure: Spin-switching from strongly coupled singlet to polarized triplet state

Abstract

Keywords

ASJC Scopus subject areas

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