Synthesis, spectra and redox properties of mononuclear five-co-ordinate copper(II) complexes with non-communicable pyrazole/pyridyl containing ligands

Synthesis and Characterization of Cu(II) and Mixed-Valence Cu(I)Cu(II) Clusters Supported by Pyridylamide Ligands

A group of copper complexes supported by polydentate pyridylamide ligands H₂bpda and H₂ppda were synthesized and characterized. The two Cu(II) dimers [Cu^II₂(Hbpda)₂(ClO₄)₂] (1) and [Cu^II₂(ppda)₂(DMF)₂] (2) were constructed by using neutral ligands to react with Cu(II) salts. Although the dimers showed similar structural features, the second-sphere interactions affect the structures differently. With the application of Et₃N, the tetranuclear cluster (HNEt₃)[Cu^II₄(bpda)₂(μ₃-OH)₂(ClO₄)(DMF)₃](ClO₄)₂ (3) and hexanuclear cluster (HNEt₃)₂[Cu^II₆(ppda)₆(H₂O)₂(CH₃OH)₂](ClO₄)₂ (4) were prepared under similar reaction conditions. The symmetrical and unsymmetrical arrangement of the ligand donors in ligands H₂bpda and H₂ppda led to the dramatic conformation difference of the two Cu(II) complexes. As part of our effort to explore mixed-valence copper chemistry, the triple-decker pentanuclear cluster [Cu^II₃Cu^I₂(bpda)₃(μ₃-O)] (5) was prepared. XPS examination demonstrated the localized mixed-valence properties of complex 5. Magnetic studies of the clusters with EPR evidence showed either weak ferromagnetic or antiferromagnetic interactions among copper centers. Due to the trigonal-planar conformation of the trinuclear Cu(II) motif with the μ₃-O center, complex 5 exhibits geometric spin frustration and engages in antisymmetric exchange interactions. DFT calculations were also performed to better interpret spectroscopic evidence and understand the electronic structures, especially the mixed-valence nature of complex 5.

Charge-assisted hydrogen bond and nitrile⋯nitrile interaction directed supramolecular associations in Cu(ii) and Mn(ii) coordination complexes: anticancer, hematotoxicity and theoretical studies

Charge-assisted H-bonds and nitrile⋯nitrile interactions directed assemblies in Cu(ii) and Mn(ii) complexes have been analyzed by MEP surface and NCI plot index. Anticancer activities and hematotoxictiy have been investigated.

Hydroxide-bridged dicopper complexes: the influence of secondary coordination sphere on structure and catecholase activity

This work illustrates the syntheses, structures and catecholase activities of dicopper(ii) complexes having a Cu(μ-OH)Cu core encased within a secondary coordination sphere intricately created by appended heterocyclic rings.

Tridentate complexes of 2,6-bis(4-substituted-1,2,3-triazol-1-ylmethyl)pyridine and its organic azide precursors: an application of the copper(II) acetate-accelerated azide-alkyne cycloaddition

Rapid coupling reactions between 2,6-bis(azidomethyl)pyridine and terminal alkynes in the presence of 5 mol% Cu(OAc)(2)·H(2)O without the addition of a reducing agent afford tridentate ligands for first-row transition-metal ions. The chelation between Cu(II) and alkylated nitrogen atoms of the azido groups of 2,6-bis(azidomethyl)pyridine, as observed in the solid state, is credited for the acceleration of the azide-alkyne cycloaddition reactions.