Two multidentate ligands utilizing triazolyl, pyridinyl and phenolate groups as donors for constructing dinuclear copper(II) and iron(III) complexes: Syntheses, structures, and electrochemistry

Abstract

Two multidentate ligands 2,2′-(1,1′-(pyridine-2,6-diylbis(methylene))bis(1H-1,2,3-triazole-4,1-diyl))bis(methylene)bis((pyridin-2-ylmethyl)azanediyl)bis(methylene)diphenol (H2LI) and N,N′-((1,1′-(pyridine-2,6-diylbis(methylene))bis(1H-1,2,3-triazole-4,1-diyl))bis(methylene))bis(1-(pyridin-2-yl)-N-(pyridin-2-ylmethyl)methanamine) (LII) containing triazolyl, phenolate and pyridinyl groups were prepared by click reaction between diazide and terminal alkynes in the presence of catalyst CuI. Both ligands were reacted with Cu2+ and Fe3+ salts to give three dinuclear complexes [LICu2](BPh4)2·2DMF (1), [LII(DMF)2Cu2](ClO4)4·H2O (2) and [LII(FeCl2)2](PF6)2 (3). All complexes were characterized by IR, UV–Vis spectra and element analysis. X-ray analysis revealed that the Cu2+ centers in complexes 1 and 2 adopted the distorted trigonal bipyramidal geometry, and the Fe3+ center in complex 3 chose an octahedral geometry. In addition, the electrochemistry of complexes 1–3 was investigated.