Linear, Edge-Sharing Heterometallic Trinuclear [CoII-LnIII-CoII] (LnIII = GdIII, DyIII, TbIII, and HoIII) Complexes: Slow Relaxation of Magnetization in the DyIII Derivative

• Published in: European journal of inorganic chemistry 2014-01, Vol.2014 (2), p.397-406
• Main Authors: Chandrasekhar, Vadapalli, Das, Sourav, Dey, Atanu, Hossain, Sakiat, Kundu, Subrata, Colacio, Enrique
• Format: Article
• Language: English
• Subjects: Cobalt; Ferromagnetic interactions; Heterometallic complexes; Lanthanides; Magnetic properties; Schiff bases
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201301171

The sequential reaction of a multisite coordination ligand (LH4) with lanthanide (III) nitrates followed by the addition of Co(NO3)2·6H2O in a 4:1:2 ratio in the presence of triethylamine afforded a series of heterometallic, linear trinuclear complexes [Co2Ln(LH3)4]·3NO3 [Ln = DyIII (1), GdIII (2), TbIII (3), and HoIII (4)]. These tricationic complexes contain nitrate counteranions. The cationic portion of these complexes consists of three metal ions that are arranged in a linear fashion; a central LnIII is present between the two terminal CoII ions and is attached to the latter through two phenoxide bridging groups. This arrangement generates two contiguous four‐membered CoLnO2 rings. The CoII ions are six‐coordinate (2N, 4O) in a distorted octahedral geometry, whereas the central lanthanide ion is eight‐coordinate (8O) in a distorted square‐antiprismatic geometry. Magnetic studies of these complexes have been performed and indicate a slow relaxation of the magnetization for the DyIII derivative 1. Linear, edge‐sharing heterometallic trinuclear [CoII–LnIII–CoII] [LnIII = Dy (1), Gd (2), Tb (3), and Ho (4)] compounds have been assembled. A slow relaxation of magnetization is observed for the DyIII derivative 1.