Two 1D carboxylate-bridged magnets displaying solvent-dependent canted antiferromagnetic ordering

Abstract

Two one-dimensional (1D) carboxylate-bridged complexes, [Mn(TAc)₂(H₂O)] (1, HTAc = thymine-1-acetic acid) and [Mn(TAc)₂(DMF)]·0.5H₂O (2), were synthesized under different solvothermal conditions, which are sensitive to solvents and pH values. The two complexes have similar 1D chain-like structures but different terminal solvent molecules (H₂O for 1 and DMF for 2), and complex 1 can be converted irreversibly to 2via single crystal to single crystal transformation. The magnetic studies reveal that 1 and 2 display solvent-dependent magnetic behaviors. 1 exhibits spin-canted and long-range antiferromagnetic ordering at T_C = 38 K and T_N = 8 K with decreasing temperature, while 2 only displays long-range antiferromagnetic ordering at T_N = 8 K. The difference may be attributed to the terminal H₂O in 1 having a greater polarity and smaller steric hindrance than the DMF molecule in 2, resulting in a more compact stacking structure of the 1D chains and more distorted octahedral geometry of the Mn^II ion to facilitate the occurrence of the spin-canted behavior.