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

Abstract

A family of copper(II)/manganese(II) new clusters with the formulas [Cu^IINa^I(L2)(MeOH)(ClO₄)] (1), [Cu^II₂Mn^II(S,S-L3)₂(MeOH)](ClO₄)₂ (2SS), [{Cu^IIMn^II(L1)(H₂O)₂(MeOH)}{Cu^II(L1)}₂](ClO₄)₂ (3), [(μ_1,3-N₃)₂{Cu^IIMn^II(L2)(H₂O)}₂{Cu^II(L2)₂](ClO₄)}₂ (4) and [(μ_1,1-N₃)₂{Cu^IIMn^II(L1)(N₃)}₂{Cu^IINa^I(L1)(MeOH)}₂](ClO₄)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.