Water Dissociation of a Dinuclear Bis(3,5‐dimethylpyrazolyl)methane Copper(II) Complex: X‐ray Diffraction Structure, Magnetic Properties, and Characteristic Absorption of the (CuN2Cl2)2 Core

• Published in: European journal of inorganic chemistry 2018-08, Vol.2018 (32), p.3644-3651
• Main Authors: Torres, Juan F., Bello‐Vieda, Nestor J., Macías, Mario A., Muñoz‐Castro, Alvaro, Rojas‐Dotti, Carlos, Martínez‐Lillo, José, Hurtado, John
• Format: Article
• Language: English
• Subjects: Absorption spectra; Antiferromagnetic coupling; Antiferromagnetism; Coordination compounds; Copper; Copper chloride; Copper compounds; Crystal structure; Crystallography; Cu2Cl2 absorption; Density functional calculations; Inorganic chemistry; Magnetic properties; Water splitting; X-ray diffraction
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201800478

A complex of formula [{CuCl{H2C(3,5‐Me2pz)}}2(µ‐Cl)2] (1) is obtained and its structure is determined by single‐crystal X‐ray diffraction crystallography, revealing dinuclear character supporting a (CuN2Cl2)2 core. Compound 1 undergoes water dissociation that generates a change in the coordination sphere of the metals, yielding a mononuclear CuII complex of the formula [CuCl{H2C(3,5‐Me2pz)2}2]Cl·3H2O (2), as supported by LeBail analysis and visible absorption spectroscopy. Interestingly, the optical features of 1 unravel characteristic patterns in the absorption spectrum, attributed solely to the formation of the (CuN2Cl2)2 core. The study of the magnetic properties of 1 reveals weak antiferromagnetic exchange coupling between the two CuII ions that is transmitted through the double‐chloro bridge, which is supported by broken‐symmetry DFT calculations. A dinuclear CuII complex, with a (CuN2Cl2)2 core, is identified by X‐ray diffraction. The complex dissociates in water, with changes in the metal coordination spheres, revealing characteristic patterns in the absorption spectrum of the Cu2Cl2 core. Experimentally, we found weak antiferromagnetic exchange coupling between the two CuII ions; this is supported by broken‐symmetry DFT calculations.