A novel two-dimensional Ni(II) fumarato complex: Solvothermal synthesis, crystal structure and magnetic properties

作者：Cernak Juraj^*; Pavlova Anna; Orendacova Alzbeta; Kajnakova Marcela; Kuchar Juraj

来源：Polyhedron, 2009, 28(14): 2893-2898.

DOI：10.1016/j.poly.2009.06.082

• Nickel(II)
• 1,10-Phenanthroline
• Fumarato ligand
• Solvothermal reaction
• X-ray structure
• Magnetic measurements
• S=1 dimer

Dark green single crystals of [Ni(fum)(phen)] (fum = fumarato, phen = 1,10-phenanthroline) (1) have been prepared under solvothermal conditions. Its crystal structure exhibits two dimensional (2D) character. The formed layers are built of dimers of crystallographically non-equivalent Ni(II) atoms linked by bridging fumarato ligands; one is of the mu(4)-bridge type with both carboxylato groups coordinated in syn-anti fashion while in the second one both carboxylate groups form a chelate-like coordination. Both Ni(II) atoms are hexa-coordinated in the cis-NiO4N2 form; two coordination positions are occupied by a N-bonded chelate phen molecule and four positions by oxygen atoms from the fum ligands. The layers are interconnected by pi-pi interactions operating between aromatic rings of the phen ligands. The analysis of the experimental thermodynamic data supports the structural assumptions and showed that magnetic subsystem of 1 can be approximated by an array of antiferromagnetic S = 1 dimers with easy-axis uniaxial magnetic anisotropy D comparable to intradimer exchange coupling J, D/J approximate to 1 and D/k(B) = -6 K. The specific heat data clearly indicate the absence of a phase transition to the ordered state at least at temperatures down to 2 K.

• 出版日期2009-9-23