Tuning The Origin Of Magnetic Relaxation Of Cyano-bridged 4f-3d Low Dimensional Molecular Magnets

This paper investigated the cyano-bridged 4f-3d coordination polymers, especially the tuning of the origin of magnetic relaxation of low-dimensional molecular magnets based on the 1-(2-hydroxyethyl)-2-pyrrolidone organic ligands. Moreover, some efforts were dedicated to the structures and magnetic properties of transition metal dicyanamide system. The main contents are described as below.1. Twelve isostructural cyano-bridged 3d-4f heterodinuclear compounds have been synthesized by solution evaporation method using 1-(2-hydroxyethyl)-2-pyrrolidone ligand, K3[Fe(CN)6] or K3[Co(CN)6], and the magnetic properties of compounds 1 YFe,2DyFe and 8DyCo were studied. Negligible magnetic coupling was indicated in compound 1YFe, antiferromagnetic intradimer interaction was operative for 2DyFe, and weak ferromagnetic coupling through dipolar-dipolar interaction was operative for 8DyCo. Under an applied direct-current field, compounds lYFe and 8DyCo showed magnetic relaxation behavior; nevertheless, compound 2DyFe appeared to be a single-molecule magnet.2. Six cyano-bridged 3d-4f hetero-metal compounds, including isostructural heterodinuclear compounds 13-14, and one-dimensional chain compounds 15-18, have been synthesized by solution evaporation method using 3-Picoline N-oxide ligand (or 2-Picoline N-oxide, Pyridine N-oxide) and K3[Fe(CN)6]. The magnetic results may indicate the antiferromagnetic interaction between DyⅢ and FeⅢ ions for compound 16DyFe.3. Eight various structural transition-metal compounds, including isomorphous compounds 19-20 with staggered double chains structures, three-dimensional network structure for compounds 21 Co, 22Ni and 24Co, one-dimensional chain structure for compounds 23Mn, 25Co and 26Co, have been synthesized by solution evaporation method using hep ligand (or 4-Picoline N-oxide, 3-Picoline N-oxide, 2-Picoline N-oxide, Pyridine N-oxide) and Na[N(CN)2]. Magnetic analyses indicated that slow magnetic relaxation behavior was occured in compound 19Co.