The mixtures of Co(X-hfpip)2; X = I and H, and bisdiazo-dipyridine ligands, D2py2(TBA), in 1:1 ratios gave the discrete cobalt complexes, 1 and 2, respectively. The molecular structures for 1 and 2 revealed by X-ray crystallography were cyclic 2:2 cobalt complexes formulated as [(Co(X-hfpip)2)2(D2py2(TBA)) 2], in which the cobalt units were compressed octahedra. After irradiation of the microcrystalline samples, the resulting Co-carbene complexes, 1c and 2c, showed SMM behaviors exhibiting slow magnetic relaxations. In dc and ac magnetic susceptibility experiments, the activation barrier, U eff, for reorientation of the magnetic moment were estimated to be 139 and 135 K for 1c and 2c, respectively, and the hysteresis loops of the magnetization (the coercive force, Hc, and 26 and 15 kOe at 1.9 K for 1c and 2c, respectively) were observed. In addition, the values of the quantum tunneling time, τQ, were determined to be 1.1 × 10 5 and 5.4 × 105 s (t1/2 = 21 and 104 h) for 1c and 2c, respectively, below 2.5 K.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry