ESR studies of ion pair formation in solutions of the triphenylene anion radical

Triphenylide-Based Molecular Solid—A New Candidate for a Quantum Spin-Liquid Compound

“…K + ions exhibit slightly off-centered coordination to singly charged triphenylide ions to achieve advantageous cation-π interactions. For the electronic structure of the K + –triphenylide ion pair the unpaired electron has been calculated to reside on the triphenylide ion, which is in agreement with the mononegative charge state supported by the Raman and visible spectroscopy and nearly free electron value of EPR g -factor. The K + –π coordination bond is thus ionic and its attractive force is also partially responsible for the out-of-plane distortion of triphenylene units.…”

“…In this work, we utilize a synthetic route involving reactions in solution generally known to result in homogeneous and crystalline products. The first reduction of PAHs with sodium was achieved by W. Schlenk already in 1914 and later a variety of reactions between PAHs and alkali metals have been successfully carried out in aprotic coordinating organic solvents. − Nevertheless, affording these materials in crystalline form, which allows the determination of crystal structure, still poses a challenge , and the unexplored electronic and magnetic response of these materials are serving with surprises.…”

“…At this point, we stress that π-interactions between the potassium cations and the benzene rings of PAH anions, present when alkali metal coordinates to PAH, ,− are expected to be strong ,− and could critically affect the structural, magnetic and transport properties of the reduced solid. The charge transfer from the alkali metal to the PAH molecule is found theoretically and experimentally to be complete ,, and as a result an ionic coordination bond is established by electrostatic forces that lead to interatomic contacts within the sum of the van der Waals radius of C and the ionic radius of the cation. , However, the effects of these interactions on the stacking motif and the possible deformation of triphenylene aromatic system and thus the emerging electronic properties have not been previously discussed for K x (C 18 H 12 ) because of lack of single-phase samples and the structural data.…”

Chromium Sandwich Complexes of Polycyclic Aromatic Hydrocarbons: Triphenylene and Fluoranthene as η6 Ligands

“…This dianion is very labile, of an EPR instrument [25] should yield spectra of the radical anions 12 Ϫ· and 13 Ϫ· . However, experiments were frustrated however, since concurrently a signal with g ϭ 2.0037 builds up which, upon expansion, is identified as being caused by by metalϪligand cleavage, possibly at the dianion stage, which could not be avoided due to insufficient control of 9 Ϫ· , the radical anion of the free ligand [26] (c). Unequivocal analysis of the EPR spectrum of 12 Ϫ· is therefore prevented the potential in the two-electrode set-up.…”

An experimental and theoretical study of the low temperature E.S.R. of the cyclooctatetraene and tetramethylcyclooctatetraene anion radicals-in single crystal environments

“…They obtained quite good agreement between the EWMO calculations and experiment. More recently, Jones and co-workers [26][27][28] have used isotropic g-values obtained from EWMO calculations of the g-tensors plus experimentally measured isotropic g-values obtained from studies of alkali metal cation-organic anion radical pairs in solution to develop models for the molecular structure of ion pairs in solution.…”