https://doi.org/10.15255/KUI.2025.019
Published: Kem. Ind. 75 (1-2) (2026) 29–40
Paper reference number: KUI-19/2025
Paper type: Original scientific paper
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Jahn-Teller Effect in Copper(II) Coordination Compounds with Halide Ions

N. Penić, O. Mišura, M. Novak and D. Vušak

Abstract

This study investigates the structural deformation of copper(II) octahedral coordination compounds caused by the Jahn-Teller effect. The analysis focuses on distortions in bond angles, bond lengths, and differences in bond lengths, with a specific comparison between cis and trans isomers. A classification system is proposed for assessing the level of octahedral distortion based on deviations from an ideal octahedron. The findings indicate that structures with weak or very weak distortions are primarily monomeric units lacking bidentate ligands, while those with strong or very strong distortions often contain bidentate ligands or consist of monomeric, dimeric, or trimeric units. The Jahn-Teller effect was found to manifest predominantly through bond distance deformations between copper and halide ions, as compared to heteroatom bonds. Additionally, elongated octahedral geometries were more prevalent than compressed ones. Of the 123 analysed structures, trans isomerism occurred more frequently, as opposed to cis isomerism. The occurrence of trans isomers increased with stronger octahedral distortions, highlighting a relationship between isomerism and the degree of geometric deformation.

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Keywords

copper(II), halides, Jahn-Teller effect, coordination compounds, crystal structures, octahedral geometry