Syntheses, structures and field-dependent slow magnetic relaxation of saddle-like Cu4 and reverse “U” shape Mn3 complexes

Abstract

Three novel complexes [Cu4(ccsa)4(Py)8] (1), [Mn3(ccsa)4(Py)6(H2O)2]·2Py·H2O (2) and [MnFe2(ccsa)4(Py)6(H2O)2] (3) (H2ccsa=3-carboxy-5-chloro-salicylald-ehyde) have been synthesized and characterized by elemental analysis, power X-ray diffraction (PXRD), Infrared (IR) spectrum and X-ray single-crystal diffraction. Complex 1 shows a rare 16-MC-4 macrocycle framework with [Cu-O-C-O] repeating unit, and four Cu ions connected by the carboxy groups from four ligands. Complexes 2 and 3 are isostructural and the metal ions exhibit reverse “U” shape arrangement. Magnetic studies reveal unexpected ferromagnetic coupling and field-dependent slow magnetic relaxation in complex 1.