Occurrence of slow relaxation of the magnetization in a family of copper(II)/manganese(II) quasi-isotropic complexes with different ground spin states.

A family of copper(II)/manganese(II) new clusters with the formulas [Cu II Na I (L2)(MeOH)(ClO 4 )] (1), [CuII2Mn II ( S , S -L3) 2 (MeOH)](ClO 4 ) 2 (2SS), [{Cu II Mn II (L1)(H 2 O) 2 (MeOH)}{Cu II (L1)} 2 ](ClO 4 ) 2 (3), [(μ 1,3 -N 3 ) 2 {Cu II Mn II (L2)(H 2 O)} 2 {Cu II (L2) 2 ](ClO 4 )} 2 (4) and [(μ 1,1 -N 3 ) 2 {Cu II Mn II (L1)(N 3 )} 2 {Cu II Na I (L1)(MeOH)} 2 ](ClO 4 ) 2 (5) with L1 = N , N '-ethylene-bis(3-methoxysalicylaldiimine), L2 = N , N '-ethylene-bis(3-ethoxysalicylaldiimine) and L3 = N , N '-cyclohexane-bis(3-ethoxysalicylaldiimine), has been synthesized, and structurally and magnetically characterized. Reduced magnetization studies demonstrate that the magnetic anisotropy of the systems is very small. However, dynamic magnetic studies and ultra-low-frequency Raman spectroscopy confirm the slow relaxation of these systems despite their quasi-isotropic nature, enlarging the range of non-anisotropic slow relaxing molecules.