Ligand field effect tuned magnetic behaviors of two chain compounds based on MnIII3O units: from slow magnetic relaxation to metamagnetism

Two chain compounds built with anti–anti acetate bridged MnIII3O units, [Mn3O(Clppz)3(EtOH)4(OAc)]n (1) and [Mn3O(Clppz)3(EtOH)2(OAc)]n (2), were synthesized and characterized. The magnetic studies indicate that 1 is a single-chain magnet with two slow magnetization relaxation processes which has for the first time been found in this type of chain complex, while 2 shows a field-induced metamagnetic behavior. The quite different magnetic behaviors resulted from the different number of coordinated ethanol molecules on the MnIII3O unit, four ethanol molecules for 1, and two ethanol molecules for 2. The best fittings to the experimental magnetic susceptibilities gave J1 = −2.72 cm−1, J2 = −4.34 cm−1, zJ = 1.24 cm−1 for 1 and J1 = −5.91 cm−1, J2 = −0.98 cm−1, zJ = 1.71 for 2 above 30 K. The positive zJ values indicate the presence of weak ferromagnetic interactions between the trinuclear units via acetate bridges in 1 and 2.