A Truly Isolated TCNQ^•- Dimer?

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

“…Another contribution could be due to the shift of TCNQ molecules in a dimer, thus effective reduction of the exchange interaction within the dimer and change of the magnetic coupling feature in the molecular crystal . The behavior of the temperature dependence of the susceptibility is also similar to what was previously reported for another RAS with non‐stacked TCNQ dimers . Here, two distinct contributions were observed by EPR: i) dimerized RAS with a quite high singlet‐triplet excitation energy and ii) the contribution of non‐dimerized spins dominating the low‐temperature magnetic properties.…”

“…The relatively high value of χT and its gradual decrease towards low temperatures cannot be described by simple Bleaney‐Bowers formula for AFM spin dimers. The presence of the relatively high ratio of crystal defects is typical for RAS, resulting in the presence of non‐dimerized (TCNQ) 2 .− entities, which have been observed in magnetic or electron‐paramagnetic resonance (EPR) measurements . As a result, we suggest that χT behavior can be described by the presence of non‐dimerized TCNQ.…”

Synthesis and characterization of cobalt(iii) cyanide complexes: cobalt participation in the decomposition of radical anion of TCNQ

“…And then, in the presence of O 2 , TCNQ 2lost the CNgroups which were transferred to the Co 3+ center and turned into the stable product DCTC -(α,α-dicyano-p-toluoylcyanide anion). 22,28,29,31,46,[50][51][52][53] The existent of CNgroups in complexes 1, 1S and 1R was supported by the typical infrared absorption of 25 -CN in the IR spectra and the element analyses of the three complexes. The orange-red powder by-product DCTCsalt formed in the reactions was confirmed by the MS analysis (m/z for C 11 N 3 OH 4 calcd 194.2, found 194.8) and the infrared study revealed both the existence of the carbonyl group (1640 cm -1 ) and 30 the cyanide group (2133-2194 cm -1 ) of DCTC -32, 39 Thus, the reaction of Co 2+ , H 2 salency and CNfrom KTCNQ provided anion [Co(CN) 2 (salency)] -.…”

Intermolecular π‐dimer of oxoverdazyl radicals with long‐distance multicenter (2e/8c) bonding via nitrogen atoms

“…Starting from the works of Hausser and Murrell1 and Kosover,2–4 numerous UV‐Vis and ESR spectroscopic studies have demonstrated the tendency of various cationic, anionic, and neutral π ‐radicals to form diamagnetic associates with characteristic absorption bands in the near‐IR region 5–24. X‐ray crystallographic measurements of these supramolecular complexes revealed ‘face‐to‐face’ arrangements of the π ‐bonded fragments with interatomic contacts of approximately 0.1–0.5 Å closer than the van der Waals separations 25–32. Spectral, structural, and thermodynamic characteristics of the radical/radical π ‐dimers appeared to be similar to the corresponding features of the molecular donor/acceptor complexes.…”

“…[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] X-ray crystallographic measurements of these supramolecular complexes revealed 'face-to-face' arrangements of the p-bonded fragments with interatomic contacts of approximately 0.1-0.5 Å closer than the van der Waals separations. [25][26][27][28][29][30][31][32] Spectral, structural, and thermodynamic characteristics of the radical/radical p-dimers appeared to be similar to the corresponding features of the molecular donor/acceptor complexes. As such, the delocalized bonding between the open-shell p-systems was originally elucidated within the framework of the Mulliken charge-transfer theory.…”