Synthesis, characterisation and computational studies on a novel one-dimensional arrangement of Schiff-base Mn3 single-molecule magnet

The syntheses, structures and magnetic properties are reported for three new manganese complexes containing the Schiff-base ((2-hydroxy-3-methoxyphenyl)methylene)isonicotinohydrazine (H(2)hmi) ligand. Complex [Mn-II(H(2)hmi)(2)(MeOH)(2)Cl-2] (1) was obtained from the reaction of H(2)hmi with MnCl2 in a MeOH-MeCN mixture. Addition of triethylamine to the previous reaction mixture followed by diethyl ether diffusion yielded a dinuclear manganese [Mn-2(III)(hmi)(2)(OMe)(2)](infinity)center dot 2MeCN center dot 2OEt(2) (2) compound. Upon increasing the MnCl2/H(2)hmi ratio, the mixed valence complex [(Mn2MnII)-Mn-III(hmi)(2)(OMe)(2)Cl-2](infinity)center dot MeOH (3) was obtained. Dc and ac magnetic measurements were carried out on all three samples. The ac susceptibility and field dependence of the magnetisation measurements confirmed that complex 3 exhibits a single-molecule magnet behaviour with an effective energy barrier of 8.1 K and an Arrhenius pre-exponential factor of 3 x 10(-9) s.