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

8 pagesInternational audienceThe syntheses, structures and magnetic properties are reported for three new manganese complexes containing the Schiff-base ((2-hydroxy 3-methoxyphenyl)methylene) isonicotinohydrazine (H2hmi) ligand. Complex [MnII(H2hmi)2(MeOH)2Cl2] (1) was obtained from the reaction of H2hmi with MnCl2 in a MeOH–MeCN mixture. Addition of triethylamine to the previous reaction mixture followed by diethyl ether diffusion yielded a dinuclear manganese [MnIII 2(hmi)2(OMe)2]•·2MeCN·2OEt2 (2) compound. Upon increasing the MnCl2/H2hmi ratio, the mixed valence complex [MnIII 2MnII(hmi)2(OMe)2Cl2]•·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 ¥ 10-9 s