Spin Cross-Over (SCO) Complex Based on Unsymmetrical Functionalized Triazacyclononane Ligand: Structural Characterization and Magnetic Properties

Magnetochemistry

Said Yefsah¹  CarlosJ. Gómez-García²  Merzouk Halit³  Smail Triki³  Mélissa Roger³  Véronique Patinec³ 

[1] Faculté des Sciences, Université Mouloud Mammeri de Tizi-Ouzou (UMTO), 15000 Tizi Ouzou, Algeria;Instituto de Ciencia Molecular (ICMol), Departamento de Química Inorgánica, Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain;University of Western Brittany, CNRS, CEMCA, 6 Avenue Le Gorgeu, C.S. 93837-29238 Brest Cedex 3, France;

关键词: Macrocycle ligands;    Iron complex;    High spin and Low spin;    Spin Cross-Over;    Magnetic properties;   

DOI  :  10.3390/magnetochemistry5010019

来源: DOAJ

【 摘 要 】

The unsymmetrical ligand 1-(2-aminophenyl)-4,7-bis(pyridin-2-ylmethyl)-1,4,7-triazacyclononane (L6) has been prepared and characterized by NMR spectroscopy. The L6 ligand is based on the triazamacrocycle (tacn) ring that is functionalized by two flexible 2-pyridylmethyl and one rigid 2-aminophenyl groups. Reaction of this ligand with Fe(ClO4)2·xH2O led to the complex [Fe(L6)](ClO4)2 (1), which was characterized as the first Fe(II) complex based on the unsymmetrical N-functionalized tacn ligand. The crystal structure revealed a discrete monomeric [FeL6]2+ entity in which the unsymmetrical N-functionalized triazacyclononane molecule (L6) acts as hexadentate ligand. As observed in the few parent examples that are based on the symmetrical N-functionalized tacn ligands, the triazacyclononane ring is facially coordinated and the N-donor atoms of the three functional groups (two pyridine and one aniline groups) are disposed in the same side of the tacn ring, leading to a distorted FeN6 environment. The magnetic studies of 1 revealed the presence of an incomplete spin crossover (SCO) transition above 425 K, whose progress would be prevented by a very exothermic thermal decomposition at ca. 472 K, as shown by thermogravimetric and DSC measurements.

【 授权许可】

Unknown