Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide

Takuma Tahara; Shuichi Suzuki; Masatoshi Kozaki; Daisuke Shiomi; Kenji Sugisaki; Kazunobu Sato; Takeji Takui; Yota Miyake; Yuko Hosokoshi; Hiroyuki Nojiri; Keiji Okada

doi:10.1002/chem.201900513

Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide

Takuma Tahara, Shuichi Suzuki, Masatoshi Kozaki, Daisuke Shiomi, Kenji Sugisaki, Kazunobu Sato, Takeji Takui, Yota Miyake, Yuko Hosokoshi, Hiroyuki Nojiri, Keiji Okada

Institute for Materials Research (IMR) (institute affiliation only)

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

16 Citations (Scopus)

Abstract

The spin–spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, (DAA-PTZ)⁺-NN⋅MBr₄⁻ (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh₃ followed by oxidation with the thianthrenium radical cation (TA⁺⋅MBr₄⁻). These salts were found to be highly stable under aerobic conditions. For the GaBr₄ salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J₁/k_B=+320 K and J₂/k_B=−2 K, respectively) were observed. The magnetic property of the Fe³⁺ salt was analyzed by using a six-spin model assuming identical intramolecular exchange interaction (J₃/k_B=+320 K) and the other exchange interactions (J₄/k_B=−7 K and J₅/k_B=−4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA-PTZ-NN to the triplet (DAA-PTZ)⁺-NN.

Original language	English
Pages (from-to)	7201-7209
Number of pages	9
Journal	Chemistry - A European Journal
Volume	25
Issue number	29
DOIs	https://doi.org/10.1002/chem.201900513
Publication status	Published - 2019 May 23

Keywords

electronic structure
magnetic properties
radical ions
redox chemistry
structure elucidation

ASJC Scopus subject areas

Catalysis
Organic Chemistry

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10.1002/chem.201900513

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@article{b614ed78cf71422b9f69b7f254ca74cb,

title = "Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide",

abstract = "The spin–spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, (DAA-PTZ)+-NN⋅MBr4− (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh3 followed by oxidation with the thianthrenium radical cation (TA+⋅MBr4−). These salts were found to be highly stable under aerobic conditions. For the GaBr4 salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J1/kB=+320 K and J2/kB=−2 K, respectively) were observed. The magnetic property of the Fe3+ salt was analyzed by using a six-spin model assuming identical intramolecular exchange interaction (J3/kB=+320 K) and the other exchange interactions (J4/kB=−7 K and J5/kB=−4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA-PTZ-NN to the triplet (DAA-PTZ)+-NN.",

keywords = "electronic structure, magnetic properties, radical ions, redox chemistry, structure elucidation",

author = "Takuma Tahara and Shuichi Suzuki and Masatoshi Kozaki and Daisuke Shiomi and Kenji Sugisaki and Kazunobu Sato and Takeji Takui and Yota Miyake and Yuko Hosokoshi and Hiroyuki Nojiri and Keiji Okada",

note = "Funding Information: This study was supported by a Grant-in-Aid for Scientific Research from JSPS KAKENHI (JP15H00956 for K.O., JP17K05790 for M.K. and K.O., JP26102005 for S.S., and JP15H03695 for Y.H.). Y.H. thanks The Mitsubishi Foundation. High-field magnetization measurements under a pulsed magnetic field were performed under the interuniversity cooperative research program of the Institute for Materials Research, Tohoku University. We thank Prof. Dr. Takashi Kubo (Osaka University) for UV/Vis/NIR measurements. Publisher Copyright: {\textcopyright} 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim",

year = "2019",

month = may,

day = "23",

doi = "10.1002/chem.201900513",

language = "English",

volume = "25",

pages = "7201--7209",

journal = "Chemistry - A European Journal",

issn = "0947-6539",

publisher = "Wiley-VCH Verlag",

number = "29",

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T1 - Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide

AU - Tahara, Takuma

AU - Suzuki, Shuichi

AU - Kozaki, Masatoshi

AU - Shiomi, Daisuke

AU - Sugisaki, Kenji

AU - Sato, Kazunobu

AU - Takui, Takeji

AU - Miyake, Yota

AU - Hosokoshi, Yuko

AU - Nojiri, Hiroyuki

AU - Okada, Keiji

N1 - Funding Information: This study was supported by a Grant-in-Aid for Scientific Research from JSPS KAKENHI (JP15H00956 for K.O., JP17K05790 for M.K. and K.O., JP26102005 for S.S., and JP15H03695 for Y.H.). Y.H. thanks The Mitsubishi Foundation. High-field magnetization measurements under a pulsed magnetic field were performed under the interuniversity cooperative research program of the Institute for Materials Research, Tohoku University. We thank Prof. Dr. Takashi Kubo (Osaka University) for UV/Vis/NIR measurements. Publisher Copyright: © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

PY - 2019/5/23

Y1 - 2019/5/23

N2 - The spin–spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, (DAA-PTZ)+-NN⋅MBr4− (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh3 followed by oxidation with the thianthrenium radical cation (TA+⋅MBr4−). These salts were found to be highly stable under aerobic conditions. For the GaBr4 salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J1/kB=+320 K and J2/kB=−2 K, respectively) were observed. The magnetic property of the Fe3+ salt was analyzed by using a six-spin model assuming identical intramolecular exchange interaction (J3/kB=+320 K) and the other exchange interactions (J4/kB=−7 K and J5/kB=−4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA-PTZ-NN to the triplet (DAA-PTZ)+-NN.

AB - The spin–spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, (DAA-PTZ)+-NN⋅MBr4− (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh3 followed by oxidation with the thianthrenium radical cation (TA+⋅MBr4−). These salts were found to be highly stable under aerobic conditions. For the GaBr4 salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J1/kB=+320 K and J2/kB=−2 K, respectively) were observed. The magnetic property of the Fe3+ salt was analyzed by using a six-spin model assuming identical intramolecular exchange interaction (J3/kB=+320 K) and the other exchange interactions (J4/kB=−7 K and J5/kB=−4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA-PTZ-NN to the triplet (DAA-PTZ)+-NN.

KW - electronic structure

KW - magnetic properties

KW - radical ions

KW - redox chemistry

KW - structure elucidation

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U2 - 10.1002/chem.201900513

DO - 10.1002/chem.201900513

M3 - Article

C2 - 30924188

AN - SCOPUS:85065202227

SN - 0947-6539

VL - 25

SP - 7201

EP - 7209

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

IS - 29

ER -

Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide

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Keywords

ASJC Scopus subject areas

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