New radical salts based on TEMPO-substituted 2,4,6-triphenylpyridinium and transition metal complexes

Series of radical salts derived from a 2,4,6-triphenylpyridinium (TPP) carrying TEMPO-substituent and transition metal complexes were prepared by the anion exchange of the TPP–TEMPO tetrafluoroborate with [n-Bu4N][Ni(dmit)2], [n-Bu4N]2[Pd(dmit)2], [n-Bu4N]2[Pt(dmit)2], [n-Bu4N][Ni(mnt)2], or [n-Bu4N]2[Ni(mnt)2] to give crystals with different structural features. While weak antiferromagnetic interactions of the Curie–Weiss behavior of S = 1/2 spin are predominantly observed in the salts of Pd(dmit)2, Pt(dmit)2 and Ni(mnt)2, the magnetic behavior of 1:1 Ni(dmit)2 salt can be explained by the additional contribution from the spins on Ni(dmit)2 anions (χ − χTEMPO), obeying the 2D Heisenberg model. A couple of the oxidized salts, [TPP][Ni(dmit)2] as well as [TPP]2[Pd(dmit)2], exhibit semi-conducting properties with relatively high room temperature conductivities.