Síntese de complexos paramagnéticos de cobre (II) com ligantes 1,2,3-triazólicos obtidos por reações de click chemistry

Abstract

In this work we described two novel paramagnetic complexes of Copper(II). These compounds were synthesized from a tetrameric ligand with 1,2,3-triazole rings. The synthesis of ligands was done Cu(I) catalyzed azides and alkynes 1,3-dipolar cycloaddition (CuAAC), a kind of Click Chemistry reaction. Four multimeric ligands were obtained: three tetrameric (L5, L6 and L8) and one trimeric (L7). Among these ligands, only the tetrameric L5 gave rise to stable coordination compounds through complexation with Cu2+ ions, arisen from Cu(NO3)2.3H2O. We obtained two distinct crystalline structures [Cu(L5)][Cu(NO3)4] (C1) and [Cu(L5)](NO3)2 (C2), both as one dimensional cationic chain. The Cu2+ ions have a square-planar geometry by coordination with four triazole groups through Cu-N bond. The study of magnetic properties of compounds C1 and C2 pointed to an antiferromagnetic behavior for both compounds, defined by weak inter and intra chain dipolar interactions among their metallic centers.