The ESR and NMR lines in powder samples of TDAE- C 60 do not show the expected frequency shifts due to long range ordering in the low temperature magnetic phase, but instead show only a relatively small line broadening below Tc=16 K. The temperature dependence of the lineshapes in ESR, the absence of a spontaneous magnetization as well as other magnetic properties suggest that the magnetic ordering below Tc=16 K is local and random, i.e. spin-glass like, rather than ferromagnetic. The possible finite-particle-size effects and possible microscopic mechanisms for the observed magnetic behavior are discussed.

ChemInform Abstract The preparation of the Schiff base ligand (I) is described. It reacts with Co acetate in EtOH to give (II) and with Fe(II) sulfate in MeOH at 60 rc C to give (III). The magnetic moment of (II) at 20 rc C indicates low-spin Co(II), its electronic spectrum is ypical for the planar structure. ESR studies measured on frozen CH2Cl2 at liquid nitrogen temp. are consistent with a square-pyramidal structure with coordination of the pendant sulfur. The structure of (III), containing high-spin Fe(III) and Fe(IV) in the uncommon low-spin tate, is based on cryomagnetic data (80-300 K), ESR and Moessbauer spectra (no yields given).

237ChemInform Abstract Variable-temp. 57Fe Mössbauer spectral and magnetic measurements for the new complexes (IV) and (IX), prepared as shown (no yields given), reveal spin-crossover behavior between S = 1/2 and 5/2 which is dependent on the temperature. Both compounds show a pronounced hysteresis effect in the high spin/low spin transition. The complex (IX) when freshly recrystallized below 280 K is predominantly in alow-spin state. However, the magnetism at room temp. increases with time, spin-crossover behavior is exhibited, and the magnetism is dependent on temp. with a pronounced hysteresis loop of about 70 K at 286 K 10 d after preparation.

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