Co, Co, and a Series of CoLn (Ln = Nd, Sm, Gd, Tb, Dy) Coordination Clusters: Search for Single Molecule Magnets.

We report herein the syntheses and investigation of the magnetic properties of a Co compound, a series of trinuclear CoLn (Ln = Nd, Sm, Gd, Tb, Dy) complexes, and a Co complex. The homometallic Co core was obtained from the reaction of Ln(NO)·xHO/Co(NO)·6HO/Hvab/EtN in a 0.5:0.5:1:2 ratio in methanol. Variation in synthetic conditions was necessary to get the desired Co-Ln complexes. The Co-Ln assembly was synthesized from Ln(NO)·xHO/Co(OAc)·4HO/Hvab/NaOMe in a 0.4:0.5:1:1 ratio in methanol. The isostructural CoLn complexes have a core structure with the general formula CoLn(Hvab)(NO)·MeOH·HO, (where Hvab = 2-[(2-hydroxymethyl-phenylimino)-methyl]-6-methoxy-phenol) with simultaneous crystallization of Co complex in each reaction. The magnetic investigation of these complexes reveals that both homometallic complexes and four Co-Ln complexes (except Co-Nd) display behavior characteristic of single molecule magnets.