Linear or Cyclic Clusters of Cu(II) with a Hierarchical Relationship

Abstract

The polydentate ligand 2,6-bis(5-(2-hydroxyphenyl)-pyrazol-3-yl)-pyridine, H4L, exhibits a series of coordination pockets favoring the establishment of metal sequences with predetermined motifs, together with a degree of flexibility for the formation of clusters with various overall topologies. With Cu(II) under strong basic conditions it has a marked tendency to stabilize a cyclic [Cu16L8] cluster. The sequential formation of this compound via [Cu7L8](2-) intermediates, recognized in its structure, is suggested by crystallographic evidence, which shows the persistent formation of the complex salt (NBu4)2[Cu7L8] in the presence of the organic cation. Also, the crystallographic identification of the related cluster [Cu11L5(OH)2(py)12] from similar reaction conditions underscores the rich multiplicity of species attainable from this simple reaction system.

Tuning CuII Coordination Polymers Derived from a Bis(pyrazolecarboxylate) Ligand by Solvothermal C–H Bond Activation: Synthesis, Structures, Catalysis, and Magnetic Properties

“…3 T, below which they decreased sharply. Therefore, the overall magnetic profiles for 1 and 2 correspond to antiferromagnetically coupled systems with singlet ground states and are similar to those of other bis(pyrazolyl)‐based Cu II complexes reported by groups such as those of Oshio, Tong, Aromi, and others 15d–15h…”

Molecular enneanuclear CuII phosphates containing planar hexanuclear and trinuclear sub-units: syntheses, structures, and magnetism

“…In practice, the two exchange constants in the isosceles triangle will have very large values and will be antiferromagnetic, leading also to a frustrated spin ground state of S = 1/2 for the Cu9 complex. In the literature there are abundant references where such NN bridging between two metal centres is part of a pyrazole, triazole, [49][50][51][52][53] or pyridazine 54 ligand. These types of ligands have been used a lot in Cu(II) complexes, since they usually afford effective exchange pathways for antiferromagnetic coupling.…”

From Metal‐Metal Bonding to Supra‐Metal‐Metal Bonding Directed Self‐Assembly: Supramolecular Architectures of Group 10 and 11 Metals with Ligands from Mono‐ to Poly‐Pyrazoles

“…Chen also synthesized an octanuclear copper(I) cluster by hydrothermal reaction. Craig et al . reported the linear or cyclic clusters of copper(II) with the polydentate ligand 2,6‐bis(5‐(2‐hydroxyphenyl)‐pyrazol‐3‐yl)‐pyridine.…”