Site-selective NMR Study of Neutral-Ionic Transition in (BEDT-TTF)(Cl,MeTCNQ)

The title compound undergoes a neutral-ionic (N-I) phase transition under pressure. In order to examine the electronic state of BEDT-TTF and Cl,MeTCNQ molecules separately by NMR, we prepared the complex with Cl,MeTCNQ and C, deuterium-substituted BEDT-TTF molecules. The 13 C and 1 H NMR measurements were performed at ambient and applied pressures. Under 8 kbar, the N-I transition was found to be continuous. We also found that the I-phase is nonmagnetic state.