Synthesis of Fe(II) and Cu(II) building blocks for metal–organic frameworks

Abstract

In situ reaction of the aminobenzoic acids 2-aminobenzoic acid and 3,5-diaminobenzoic acid with salicylaldehyde provide easy access to the ligands 2-[{(2-hydroxyphenyl)methylene}amino]benzoic acid (L1) and 3,5-bis[{(2-hydroxyphenyl)methylene}amino]benzoic acid (L2). Addition of a Fe(II) or Cu(II) salt to the solution of the ligand yields the corresponding Fe and Cu complexes. The species synthesized have been structurally characterized by single-crystal X-ray diffraction. The Fe(II) complex [Fe(L1)(MeOH) 3] ( 1) crystallizes in the triclinic space group P 1 ¯ . The Cu(II) complex [Cu(L1)] ( 2) is a one-dimensional chain and crystallizes in the monoclinic space group P2 1. The Cu(II) complex [Et 3NH] 2[Cu 2(L2) 2] ( 3) crystallizes in the monoclinic space group P2 1/ n. The magnetic properties of 1, 2 and 3 have been studied, showing that the Cu(II) ions of 2 and 3 are ferromagnetically coupled. Complexes 1 and 3 have strong potential as metal-bearing building blocks for the synthesis of metal–organic frameworks.