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Stabilization of Pancake Bonding in (TCNQ)₂.⁻ Dimers in the Radical‐Anionic Salt (N−CH₃−2‐NH₂−5Cl−Py)(TCNQ)(CH₃CN) Solvate and Antiferromagnetism Induction

Starodub, Tetiana N.; Čižmár, Erik; Kliuikov, Andrii; Starodub, Vladimir A.; Feher, Alexander; Kozlowska, Mariana

Abstract (englisch):
We report a new antiferromagnetic radical‐anion salt (RAS) formed from 7,7,8,8‐tetracyanquinonedimethane (TCNQ) anion and 2‐amino‐5‐chloro‐pyridine cation with the composition of (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN). The crystallographic data indicates the formation of (TCNQ)2.− radical‐anion π‐dimers in the synthesized RAS. Unrestricted density functional theory calculations show that the formed π‐dimers characterize with strong π‐stacking “pancake” interactions, resulting in high electronic coupling, enabling efficient charge transfer properties, but π‐dimers cannot be stable in the isolated conditions as a result of strong Coulomb repulsions. In a crystal, where (TCNQ)2.− π‐dimers bound in the endless chainlets via supramolecular bonds with (N−CH3−2‐NH2−5‐Cl−Py)+ cations, the repulsion forces are screened, allowing for specific parallel π‐stacking interactions and stable radical‐anion dimers formation. Measurements of magnetic susceptibility and magnetization confirm antiferromagnetic properties of RAS, what is in line with the higher stability of ground singlet state of the radical‐anion pair, calculated by means of the DFT. Therefore, the reported radical‐anion (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN) solvate has promising applications in novel magnetics with supramolecular structures.

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Verlagsausgabe §
DOI: 10.5445/IR/1000096738
Veröffentlicht am 23.07.2019
Coverbild
Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2019
Sprache Englisch
Identifikator ISSN: 2191-1363, 2191-1363
KITopen-ID: 1000096738
HGF-Programm 43.21.04 (POF III, LK 01)
Erschienen in ChemistryOpen
Band 8
Heft 7
Seiten 984–988
Vorab online veröffentlicht am 18.07.2019
Nachgewiesen in Web of Science
Scopus
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