Том 56, № 4 ЖУРНАЛ СТРУКТУРНОЙ ХИМИИ Июль UDC 548.73:541.49:546.72:546.21 CRYSTAL STRUCTURE, SPECTROSCOPIC AND MAGNETIC PROPERTIES OF A NEW IRON(III) COMPLEX J. Abdelhak, S.N. Cherni, M.F. Zid, A. Driss Laboratoire de Matйriaux et Cristallochimie, Dйpartement de Chimie, Facultй des Sciences de Tunis, Universitй de Tunis, Tunis, Tunisie E-mail: jawher.abdelhak@ipein.rnu.tr Received November, 26, 2013 Revised — March, 9, 2014 We report herein the synthesis and physicochemical characterization of a new mixed-ligand iron(III) complex of the formula (C5H6ClN2)[Fe(C2O4)2(H2O)2]⋅2H2O. <...> This compound is prepared by slow evaporation at room temperature and characterized by single crystal X-ray diffraction. <...> It is characterized by IR and UV-VIS spectra and thermal analysis (TG and DTA). <...> In this compound, the iron ion has a slightly distorted square bipyramidal environment, coordinated by two chelating oxalate ions and two water molecules. <...> Structural cohesion is essentially established by π—π interactions between the rings of pyridine groups and intermolecular hydrogen bonds connecting the ionic entities and uncoordinated water molecules. <...> Magnetic susceptibility measurements exhibit the paramagnetic behavior at high temperatures. <...> However, at low temperatures, the magnetic data show the occurrence of weak antiferromagnetic intermolecular interactions between the local spins. <...> DOI: 10.15372/JSC20150407 Keywords: crystal structure, iron(III) complex, thermal behavior, visible and ultraviolet spectrometers, magnetic properties. <...> INTRODUCTION Several years ago, numerous oxalate complexes have been synthesized and investigated due to their extensive application in various fields such as medical, pharmaceutical, biological, and even industrial [ 1, 2 ]. <...> This is due to the ability of the oxalate ligand to efficiently transmit magnetic interactions through its bridging mode [ 3 ]. <...> Its planar shape, negative charge, and good donor ability because of the presence of four oxygen donors make this ligand very appropriate to build coordination polymers in its interaction with metal ions. <...> The versatility of oxalate as a ligand is well illustrated by the variety of coordination modes. <...> Further, because of our interest in the magnetic properties of polymeric three-dimensionally linked complexes with chelating oxalate ions as bridging ligands, further <...>