Structurally Diverse Copper(II) Complexes of Polyaza Ligands Containing 1,2,3-Triazoles: Site Selectivity and Magnetic Properties

Abstract

Copper(II) acetate mediated coupling reactions between 2,6-bis(azidomethyl)pyridine or 2-picolylazide and two terminal alkynes afford 1,2,3-triazolyl-containing ligands L(1)-L(6). These ligands contain various nitrogen-based Lewis basic sites including two different pyridyls, two nitrogen atoms on a 1,2,3-triazolyl ring, and the azido group. A rich structural diversity, which includes mononuclear and dinuclear complexes as well as one-dimensional polymers, was observed in the copper(II) complexes of L(1)-L(6). The preference of copper(II) to two common bidentate 1,2,3-triazolyl-containing coordination sites was investigated using isothermal titration calorimetry and, using zinc(II) as a surrogate, in (1)H NMR titration experiments. The magnetic interactions between the copper(II) centers in three dinuclear complexes were analyzed via temperature-dependent magnetic susceptibility measurements and high-frequency electron paramagnetic resonance spectroscopy. The observed magnetic superexchange is strongly dependent on the orientation of magnetic orbitals of the copper(II) ions and can be completely turned off if these orbitals are arranged orthogonal to each other. This work demonstrates the versatility of 1,2,3-triazolyl-containing polyaza ligands in forming metal coordination complexes of a rich structural diversity and interesting magnetic properties.

Integrated and Passive 1,2,3-Triazolyl Groups in Fluorescent Indicators for Zinc(II) Ions: Thermodynamic and Kinetic Evaluations

“…12,38,50–55 We developed an experimental procedure based on Scheme 3 that allows for determining the affinity of N3 of 1,2,3-triazolyl group (see numbering in Scheme 3A) to zinc(II), which accounts for the difference in zinc(II) affinities of L14 and L15 .…”

“…11,12 The renaissance of 1,2,3-triazole chemistry is primarily due to the discovery by Fokin, Sharpless, 13 and Meldal 14 of regiospecific synthesis of 1,4- disubstituted-1,2,3-triazoles via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). It was later shown that 1,5-disubstituted-1,2,3-triazoles can be prepared also regioselectively using Ru- or base-catalyzed approaches (Scheme 1).…”

Computational investigations of click-derived 1,2,3-triazoles as keystone ligands for complexation with transition metals: a review

“…8,79,80 These bidentate click ligands form rhenium(I) complexes with a 1 : 1 metal : ligand ratio. The complexes of these ligands have wide applications in electronic 81,82 and luminescent 29,[83][84][85][86][87][88][89] materials, catalysts, [90][91][92] and in metallo-pharmaceuticals.…”

Synthesis, structure, stability and antimicrobial activity of a ruthenium(II) helicate derived from a bis-bidentate “click” pyridyl-1,2,3-triazole ligand

“…We [39][40][41][42][43][44] and others [45][46][47][48][49][50][51][52][53][54][55] have explored the use of 1,4-disubstituted 1,2,3-triazole containing ''click'' ligands in the development of functionalized metallosupramolecular architectures and have shown that metallomacrocycles, cages and helicates can be readily generated. As part of that work we developed a small family of bis-2-(1-R-1H-1,2,3-triazol-4-yl)pyridine ligands 1 [56] (Scheme 1) and showed that they would assemble into [Fe 2 L 3 ] 4+ metallosupramolecular helicates [57] when treated with Fe(II) ions.…”