Effect of the Co-C(C60-) bond formation on magnetic properties of the ionic complex {cryptand[2,2,2]•(Na+)}•{CoIITPP•(C60-)}•(C6H4Cl2)2

A new ionic complex {cryptand[2,2,2]center dot(Na+)}center dot{(CoTPP)-T-II center dot(C-60(-))}center dot(C6H4Cl2)(2) has been obtained as single crystals by a diffusion technique. It involves coordination {(CoTPP)-T-II center dot(C-60(-))} units and bulky {cryptand[2,2,2]center dot(Na+)} cations. The Co-C(C-60(-)) coordination bond is short (2.262(2) angstrom at 100 K) which provides ordering in the C-60(-) anions. This is the first ordered structure of {(CoTPP)-T-II center dot(C-60(-))}. The coordination bonds weaken upon heating to be 2.316(4) angstrom at 250 K. As a result, the C-60(-) anions begin to rotate at 250 K about the Co-C bond between two orientations. The complex is diamagnetic from 4 up to 320 K. The Co-C bonds dissociate above 320 K only to form unbound paramagnetic (CoTPP)-T-II and C-60(center dot-) species. The process is accompanied by the reversible increase in magnetic susceptibility of the complex and the appearance of a new broad EPR signal with g = 2.1187 and a linewidth of similar to 120 mT (350 K). The signal was attributed to both paramagnetic (CoTPP)-T-II and C-60(center dot-),which showed strong exchange interaction.