DETERMINATION OF THE SPIN-DENSITY DISTRIBUTION IN THE ORGANIC CONDUCTOR DMTM(TCNQ)(2) WITH C-13 MAGIC-ANGLE-SPINNING NMR

C-13 magic angle spinning (MAS) NMR experiments on the organic conduct or N,N-dimethylthiomorpholinium bis-tetracyanoquino-dimethane [DMTM(TC NQ)(2)] isotopically enriched at the position of the C-2 carbons of TC NQ are reported. Two isotropic resonances are resolved above the struc tural phase transition at 272 K, both exhibiting large positive isotro pic and anisotropic Knight shifts. Sideband analysis of the MAS spectr a has yielded the complete Knight shift tensors above T-c, in the insu lating state. From the Knight shifts the hyperfine couplings and spin densities at the C-2 sites were calculated and were found to be in goo d agreement with molecular calculations. Below T-c, the sideband patte rn displays two jets of C-13-2 lines indicating a spin density distrib ution between two sites of 0.59:0.41.