Ligand field effect tuned magnetic behaviors of two chain compounds based on Mn3IIIO units: from slow magnetic relaxation to metamagnetism

Two chain compounds built with anti-anti acetate bridged (Mn3O)-O-III 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 (Mn3O)-O-III unit, four ethanol molecules for 1, and two ethanol molecules for 2. The best fittings to the experimental magnetic susceptibilities gave J(1) = -2.72 cm(-1), J(2) = -4.34 cm(-1), zJ = 1.24 cm(-1) for 1 and J(1) = -5.91 cm(-1), J(2) = -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.