15N and 13C NMR study of (DMe-DCNQI)2Cu

In order to investigate the electronic state of the metallic (DMe-DCNQI)2Cu, we prepared isotope-enriched DMe-DCNQI molecules where each site of NCN was substituted by 13C and 15N and performed 13C and 15N-NMR measurements. Using the spectra of (DMe-DCNQI)2Li with no magnetic contribution from metal ion as reference, we succeeded in separating the two contributions to the Knight shift; the DCNQI π part and the Cu ion part, which could be probed through the coordinated N atom.