New Metal-Organic Systems with a Functionalized Oxamate-Type Ligand and MnII, FeII, CuII and ZnII

• Autor(a) principal: Maciel,Jhonny W.
• Data de Publicação: 2019
• Outros Autores: Kalinke,Lucas H. G., Valdo,Ana K., Martins,Felipe T., Rabelo,Renato, Moliner,Nicolás, Cano,Joan, Julve,Miguel, Lloret,Francesc, Cangussu,Danielle
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532019001102413
• topic: iron(II); manganese(II); zinc(II); copper(II); oxamate; magnetic properties; single-ion magnet

Four new complexes of formula [Fe(H2pcpa)2(H2O)2] (1), {[Mn(Hpcpa)(H2O)3]•1/2H2O}n (2), {[Zn(Hpcpa)(H2O)3]•1/2H2O}n (3) and [Cu2(Hpcpa)2(bipy)2]•8H2O (4) [H3pcpa = N-(4-carboxyphenyl)oxamic acid; bipy = 2,2¢-bipyridine] have been synthesized and their structures determined by X-ray diffraction. The structure of 1 consists of mononuclear iron(II) units where each iron(II) ion is six-coordinate by two trans-positioned water molecules and two bidentate H2pcpa- ligands building a distorted octahedral environment. 2 and 3 consist of neutral zigzag chains of MnII and ZnII ions respectively, the Hpcpa2- groups acting as linkers in a bidentate/monodentate coordination mode with three mer-positioned water molecules achieving the six-coordination around the metal centers. Compound 4 is a neutral centrosymmetric dicopper(II) complex where two Hpcpa2- groups adopting the bidentate/monodentate coordination mode and act as bridges and bidentate bipy molecules act as end-cap ligands, describing a square pyramidal surrounding around each copper atom. Cryomagnetic measurements for 1, 2 and 4 in the temperature range 1.9-300 K reveal the occurrence of a field-induced single-ion magnet (SIM) behavior (1) and weak interchain (J = -0.22 cm-1, 2) and intradimer (J = -0.39 cm-1, 4) antiferromagnetic interactions, the Hamiltonian being defined as H = -J Sa.Sb.