ESR Studies of Cobalt(II) in [TMPD+]2[Ni(mnt)2] and [TMPD+]2[Pt(mnt)2](TMPD+: N,N,N′,N′-Tetramethyl-p-phenylenediamine Cation, mnt: 1,2-Dicyano-1,2-ethylenedithiolato)

The Co(II) and triplet exciton ESR spectra of Co(II)-doped [TMPD+]2[Ni(mnt)2] and [TMPD+]2[Pt(mnt)2] were observed at different temperatures. The triplet exciton signals of the solid solutions yielded practically the same ESR parameters as those of the pure Ni(II) and Pt(II) complexes. The Co(II) spectra showed a wellresolved hyperfine structure, each component line of which became broad with increasing temperature. This can be interpreted in terms of exciton transfer from TMPD+ lattices to the metal ions.