Supramolecular Assemblies of Trinuclear Copper(II)-Pyrazolato Units: A Structural, Magnetic and EPR Study

Abstract

<jats:p>Two anionic complexes, {[Cu3(µ3-OH)(µ-4-Ph-pz)3Cl3]2[Cu(4-Ph-pzH)4](µ-Cl)2}2− (1) and [Cu3(µ3-OH)(µ-pz)3(µ1,1-N3)2(N3)]− (2), crystallize as one-dimensional polymers, held together by weak Cu-(µ-Cl) and Cu-(µ-N3) interactions, respectively. Variable temperature magnetic susceptibility analyses determined the dominant antiferromagnetic intra-Cu3 exchange parameters in the solid state for both complexes, whereas the weak ferromagnetic inter-Cu3 interactions manifested also in the solid state EPR spectra, are absent in the corresponding frozen solution spectra. DFT calculations were employed to support the results of the magnetic susceptibility analyses.</jats:p>

Capped Nanojars: Synthesis, Solution and Solid-State Characterization, and Atmospheric CO2 Sequestration by Selective Binding of Carbonate

“…Trinuclear units can be assembled into discrete hexanuclear units if L is a bridging ligand, such as pyrazolate, − NCS – , or 4,4′-bipyridine, or if L or additional coordinating species, such as Cl, , carboxylates, − sulfate, , perchlorate, , or nitrate, act as bridging ligands by binding to the axial position of one or multiple Cu II ions. If L is a di- or tricarboxylate ligand or 4,4′-bipyridine (or its derivatives), then metal–organic frameworks − or coordination polymers − can be obtained. Various discrete higher-nuclearity copper­(II) pyrazolate complexes are also known. − …”

Spin Frustrated Pyrazolato Triangular CuII Complex: Structure and Magnetic Properties, an Overview

“…However, the opposite phenomenon is observed (Figure 5). We have performed DFT calculations to rationalize the magnetic properties observed for 1−Cu3 (see Materials and Methods section) [23]. The results were compared to a previously reported theoretical study on the magnetic properties of several μ3−OH − -bridged trinuclear Cu II complexes [26].…”

“…The results were compared to a previously reported theoretical study on the magnetic properties of several μ3−OH − -bridged trinuclear Cu II complexes [26]. The theoretical calculations for 1−Cu3 were carried out at We have performed DFT calculations to rationalize the magnetic properties observed for 1−Cu3 (see Materials and Methods section) [23]. The results were compared to a previously reported theoretical study on the magnetic properties of several µ 3 −OH −bridged trinuclear Cu II complexes [26].…”

“…This has allowed for the possibility of studying the magnetic properties of geometrically spin-frustrated systems in detail [21]. Among these systems, the ones with a hydroxy bridge (µ 3 −OH − ) are among the most reported in the literature [22,23]. Systems presenting pyrazolato, triazolato, and other types of auxiliary organic ligands, have been magnetically studied in the literature [24,25].…”

Supramolecular Chemistry in the 3rd Millennium

“…Supramolecular interactions play a vital role in the assembly of molecular helicates, and it is therefore fitting that this area of chemistry is represented in this themed issue -the assembly of enantiopure M 4 L 4 helicates is described in a study from Turner and coworkers [11]. Moving from multinuclear helicates to coordination polymers takes us on to contributions that describe supramolecular assemblies containing trinuclear copper(II)pyrazolato units (Raptis, Boudalis, Herchel and coworkers) [12] and chloro-substituted pyrazin-2-aminocopper(I) assemblies featuring hydrogen bond and halogen bond interactions (Mailman, Rissanen and coworkers) [13]. Halogen bonds are a relatively new addition to the array of supramolecular interactions and also feature in the assembly of architectures comprising tetrakis(4-(iodoethynyl)phenyl)methane and 1,3,5,7-tetrakis(4-(iodoethynyl)phenyl)adamantane building blocks (Aakeröy and coworkers) [14].…”