Open AccessStabilization of Pancake Bonding in (TCNQ) 2 .− Dimers in the Radical‐Anionic Salt (N−CH 3 −2‐NH 2 −5Cl−Py)(TCNQ)(CH 3 CN) Solvate and Antiferromagnetism Induction
Author(s) -
Starodub Tetia.,
Čižmár Erik,
Kliuikov Andrii,
Starodub Vladimir A.,
Feher Alexander,
Kozlowska Mariana
Publication year - 2019
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201900179
Subject(s) - chemistry , crystallography , antiferromagnetism , supramolecular chemistry , stacking , pyridine , ion , magnetic susceptibility , radical ion , crystal structure , salt (chemistry) , density functional theory , magnetization , singlet state , computational chemistry , medicinal chemistry , organic chemistry , physics , quantum mechanics , magnetic field , nuclear physics , excited state , condensed matter physics
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−CH 3 −2‐NH 2 −5Cl−Py)(TCNQ)(CH 3 CN). 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−CH 3 −2‐NH 2 −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−CH 3 −2‐NH 2 −5Cl−Py)(TCNQ)(CH 3 CN) solvate has promising applications in novel magnetics with supramolecular structures.