Search

Two nickel(II) complexes were synthesized and structurally as well as magnetically characterized by using two positional isomeric nitronyl nitroxide radical ligands and H3cda as co-ligand: [Ni(NIToPy)(cda)]H2O ·CH3OH ( 1) and [Ni(IM4Py)2(cda)H2O] ( 2) [NIToPy = 2-(3′-pyridinyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide; IM4Py = 2-(4′-pyridinyl)-4,4,5,5-tetramethylimidazoline-l-oxyl; H3cda = 4-hydroxypyridine-2,6-dicarboxylic acid]. Single-crystal structures analyses show that both complexes have similar mononuclear structures, in which the central NiII ions are hexacoordinated with a distorted octahedral arrangement. The magnetic properties of 1 and 2 were studied, and antiferromagnetic interactions between NiII ion and radicals are observed. [ABSTRACT FROM AUTHOR]

The tetranuclear nickel cluster {[Ni4(L)4(C2H5OH)4]· 7H2O} (1) was synthesized based on the tridentate Schiff base ligand H2L = 1-phenyl-3-[(2-hydroxyphenyl)imino]-1-butanone. The structure of 1 was determined by single-crystal X-ray diffraction. It exhibits a discrete [Ni4O4] cluster. Magnetic studies indicate that ferromagnetic interactions exist within compound 1. Furthermore, thermogravimetric analysis and PXRD patterns in various solvents reveal thermal and solvent stability of compound 1. [ABSTRACT FROM AUTHOR]

With formate as ligand, one discrete dragonfly-like 3d-4f cluster showing beautiful pyramidal metal skeleton, [GdCu4(HCOO)5(μ3-OH)4(NO3)2(H2O)7](H2O) ( 1Gd), was obtained by a self-assembly reaction of Gd(NO3)3, Cu(NO3)2, and formate ligand. The two nitrates could be treated as the 'wings' of the 'dragonfly', and the formate with a free oxygen atom could be regarded as the 'tail'. When using perchlorate instead of nitrate, two series of 1D compounds based on the similar pyramidal [ LnCu4] unit, linear {[GdCu4(HCOO)5(μ3-[OH)4(H2O)8](ClO4)2(H2O)2} n ( 2Gd) and zigzag {[ LnCu4Na2(HCOO)4(μ3-OH)4(H2O)9(ClO4)5](H2O)2} n [ Ln = Gd, ( 3Gd); Dy, ( 3Dy)] were synthesized by controlling the formate amount. They used μ5-η1:η4 formate or [Na2(ClO4)4]2- unit as connectors to link the neighboring [ LnCu4] units together, respectively. Magnetic analyses reveal that these four compounds all show ferromagnetic interactions, and 3Dy displays slow relaxation of the magnetization. [ABSTRACT FROM AUTHOR]