Structure–Property Relationship of Supramolecular Rotators of Coronene in Charge-Transfer Solids

Abstract

Single crystals of charge-transfer (CT) complexes composed of the polyaromatic hydrocarbon, coronene, as an electron donor (D) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) analogues as electron acceptor (A) were obtained. Elucidation of crystal structures of CT complexes enables a systematic investigation of dynamic properties of coronene molecules lying in different types of crystalline environments. Solid-state 2 H NMR spectra of CT complexes formed with deuterated coronene confirmed the in-plane 6-fold flipping motion of the coronene molecules. The dihedral angle between adjacent coronene and TCNQ analogue within the DA-type alternating π-column is closely correlated with the dynamic properties, such as rotational rate and activation energy. Side-by-side intermolecular hydrogen-bonding also seems to have an effect in ways that lead to the suppressed rotation. These findings would provide an initial step toward the selection, design, and engineering of counter components of supramolecular rotators in the CT solids.

Conducting π Columns of Highly Symmetric Coronene, The Smallest Fragment of Graphene

“…(b) Molecular structure of coronene; the 12 rim carbon atoms are numbered 1–12. Deviations from the average value of the distances of the carbon atoms from the molecular centroid (Δ d ) are shown on cobweb charts for (c) the neutral solid (coronene)(F 4 TCNQ), (d) 1 , (e) 2 , and (f) a coronene monocation with a structure optimised by DFT ( D 2 h symmetry with a 2 A u electron configuration), in which the carbon atom with the highest Δ d is numbered 1. In (d) and (e), the red and blue plots indicate the geometries of the A and B molecules, respectively.…”

“… Raman‐active A 1g band of 1 , 2 , (coronene) 3 Mo 6 Cl 14 ( 3 ), the neutral solid (coronene)(TCNQ) and pristine coronene at room temperature. For 3 , the dotted lines indicate the Lorentzian functions, which show splitting of the A 1g band due to charge disproportionation.…”

“…Because variation of electronic properties caused by rotational and orientational changes of C 60 molecules has been observed for several alkali‐doped fullerides, we investigated the in‐plane rotation of the coronene molecules in the present solids and compared their behaviour with those of coronene molecules in various arrangements . Solid‐state NMR spectroscopy is one of the most definitive experimental techniques for investigating the dynamic properties of molecules in the solid form.…”

“…The observed powder pattern indicates in‐plane flipping motion of the coronene molecules in the solid, instead of continuous motion. Although the simulations assuming in‐plane six‐fold (nearest neighbour jumps) and three‐fold (next‐nearest neighbour jumps) flipping motions are indistinguishable from each other, we applied the former model, as in our previous papers . The in‐plane six‐fold flipping model for a 1:2 ratio on two motional sites implies that the two rotators can be attributed to the faster‐rotating B and slower‐rotating A , respectively, because the crystallographic study suggests that B is much more loosely packed than A in 2 .…”

Self‐Healing Behavior in a Thermo‐Mechanically Responsive Cocrystal during a Reversible Phase Transition

“…[17,18] Following this research direction, we believe that these reversible molecular-level motions could be amplified into the macroscopic regime by cocrystallization synergy.Furthermore,ifexternal-mechanical-response function is introduced into these well-designed cocrystals,the relationships between these mechanical responses and key intermolecular interactions can be concluded more precisely. [17,18] Following this research direction, we believe that these reversible molecular-level motions could be amplified into the macroscopic regime by cocrystallization synergy.Furthermore,ifexternal-mechanical-response function is introduced into these well-designed cocrystals,the relationships between these mechanical responses and key intermolecular interactions can be concluded more precisely.…”