A Binuclear Copper(II) Complex with Diphenoxido-bridges: Synthesis, Characterisation, Crystal Structure and Predicting the Magnetic Coupling Constant

Abstract

Reaction of copper(II) acetate with 1,1′-[(2,2-dimethylpropane-1,3-diyl)bis(nitrilomethylidyne)]-di-2-naphthol (H2L) gave the diphenoxido-bridged binuclear copper(II) complex [Cu2L2]. Its crystal structure shows a slightly distorted square pyramidal geometry around both of the copper(II) ions. In the symmetric Cu2O2 core, each of the phenoxido bridges occupies an equatorial position around one of the copper(II) centres. A broken symmetry (BS) computation based on density functional theory (DFT) evaluated the magnetic interaction in the complex using the (U)B3LYP level of theory in association with the basis sets LANL2DZ for the copper atoms and 6-31G** for the other atoms. The calculations showed ferromagnetic interaction between the two magnetic copper(II) centres with a magnetic coupling constant (J) of 1.16 cm−1.

A Semiconducting Copper(II) Coordination Polymer with (4,4) Square Grid Topology: Synthesis, Characterization, and Application in the Formation of a Photoswitch

“…This tendency is similar to those described by Ruiz et al for similar hydroxo- and alkoxo-bridged complexes. However, these later complexes show weaker antiferromagnetic couplings and even ferromagnetic for small Cu–O–Cu angles, while flat macrocyclic phenoxo-bridged complexes show antiferromagnetic interactions in a broad range of angles. , High values of the out-of-plane angle (τ) of the phenyl rings, that is, when the phenyl groups are not in the Cu 2 O 2 plane, favor the ferromagnetic contributions. ,,, However, this parameter has more influence in the variation of the coupling constants when the phenyl rings of the phenoxo ligands present a syn conformation. , In this case, the antiferromagnetic coupling is enhanced for values of τ in the range 0–20° whereas the contrary occurs for τ > 20°. On the contrary, the out-of-plane angle does not have a very important effect if the phenyl rings show an anti conformation, although the ferromagnetic contribution is slightly favored for high values of τ.…”

“…High torsion angles reduce the antiferromagnetic couplings and favor the ferromagnetic contribution. Although in copper­(II) dimers with pentacoordinate environment the magnetic exchange can be influenced by the type of connection, such as axial–equatorial, ,, basal–basal, , or basal–apical, , this variable is not considered for octahedral environments.…”

“…52,56 High values of the out-of-plane angle (τ) of the phenyl rings, that is, when the phenyl groups are not in the Cu 2 O 2 plane, favor the ferromagnetic contributions. 31,53,56,58 However, this parameter has more influence in the variation of the coupling constants when the phenyl rings of the phenoxo ligands present a syn conformation. 31,53 In this case, the antiferromagnetic coupling is enhanced for values of τ in the range 0−20°w hereas the contrary occurs for τ > 20°.…”

Polyphenol oxidase activities by cobalt (II) complex with Benzopyran Derivatives, Synthetic, Characterization, Kinetics Study and Molecular Modeling Studies

“…A strong band observed at 2186 cm -1 is likely to be due to νC≡N [29] Vibration absorption bands which appeared at 3447 cm -1 with one at 3332 cm -1 are assigned to νNH2. The ligand also shows band at 1664cm -1 assigned to νC=O [30] .…”