Controlling the construction of trinuclear, 1-D, and 2-D Ni(ii)Fe(ii)/Fe(ii)Fe(ii) complexes: selective syntheses, structures, and magnetic properties

The reaction of [Ni(bpca)2] (1) and [Fe(H2O)6](ClO4)2 gave a trinuclear complex 3, five 1-D chain complexes 4a–e, and a 2-D honeycomb complex 5. The selective syntheses of these complexes were achieved by controlling the reaction conditions such as reaction stoichiometry, solvents, and the presence/absence of supporting ligands. 3 consists of a central {Fe(trans-H2O)2}2+ moiety and two units of 1 acting as terminal bidentate ligands. 4a–e consist of an alternating arrangement of Fe(II) ions and 1 which acts as a bis-bidentate bridging ligand. 5 has a honeycomb structure with hexagons involving twelve metal ions, six Ni(II) ions in 1 and six Fe(II) ions, and holds the large cavity which includes counter ions, chloroform, and water molecules. The reaction of [Fe(bpca)2] (2) and [Fe(H2O)6](ClO4)2 also gave a 2-D honeycomb complex 6 which is isostructural to 5. Magnetic data for 3 and 4a indicate a ferromagnetic interaction between adjoining Ni(II) ions and the Fe(II) ions, due to the strict orthogonality of the magnetic orbitals.