Synthesis and properties of iron (II) quinoline-2-carboxylates, crystal structure of trans-diaquabis(quinoline-2-carboxylato)iron (II) bis(dichloromethane) solvate

Abstract

Two mononuclear iron complexes with the quinoline-2-carboxylate ion (quin-2-c ion) have been obtained by the reaction of iron powder with quinoline-2-carboxylic acid in dichloromethane. The compounds [Fe(quin-2-c) 2] ( 1), [Fe(quin-2-c) 2(H 2O) 2] · 2CH 2Cl 2 ( 2) and [Fe(quin-2-c) 2(H 2O) 2] · 2EtOH · 2H 2O ( 3) have been investigated by IR and UV–Vis spectroscopy, magnetic susceptibility and field-dependent magnetization measurements. The structure of 2 has been characterised by X-ray diffraction. The 2D bilayered frameworks of 2 and 3 are constructed by extensive hydrogen bonding interactions between water and the organic ligand coordinated to iron (II). The magnetic properties of 2 and 3 were interpreted on the basis of a spin Hamiltonian that included axial and rhombic crystal field components. The weak antiferromagnetic ( 2) and ferromagnetic ( 3) interactions are evident in the low temperature data and possibly occur via strong hydrogen bonds.