Synthesis, Characterization, and Preliminary In Vitro Anticancer Activity of Zinc Complexes Containing Amino Acid-Derived Imidazolium-Based Dicarboxylate Ligands

Coordination polymers containing zinc and imidazolium-based dicarboxylate ligands, [L<sup>R</sup>]<sup>−</sup>, were synthesized by reacting zinc acetate with HL<sup>R</sup> compounds, <b>1</b>. The resulting complexes were characterized and structural...

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Detalles Bibliográficos
Autores: Carrasco-Carrasco, Carlos Jesús, Pastor, Antonio, Conejo, María del Mar, Álvarez, Eleuterio, Calderón-Montaño, José Manuel, López-Lázaro, Miguel, Galindo, Agustín
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/385757
Acceso en línea:http://hdl.handle.net/10261/385757
Access Level:acceso abierto
Palabra clave:Zinc
Anticancer
Selectivity
Amino acid
Imidazolium-dicarboxylate
X-ray
Descripción
Sumario:Coordination polymers containing zinc and imidazolium-based dicarboxylate ligands, [L<sup>R</sup>]<sup>−</sup>, were synthesized by reacting zinc acetate with HL<sup>R</sup> compounds, <b>1</b>. The resulting complexes were characterized and structurally identified using single-crystal X-ray diffraction, revealing polymeric structures for the complexes [Zn(L<sup>R</sup>)<sub>2</sub>]<sub>n</sub> (R = Gly, <b>2a</b>; βAla, <b>2b</b>) and [Zn(L<sup>Leu</sup>)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]<sub>n</sub> (<b>2c</b>). In these structures, the [L<sup>R</sup>]<sup>−</sup> ligands adopt a bridging monodentate μ-κ<sup>1</sup>-O<sup>1</sup>,κ<sup>1</sup>-O<sup>3</sup> coordination mode, resulting in distorted tetrahedral (<b>2a</b>, <b>2b</b>) or octahedral (<b>2c</b>) geometries around the zinc center. When the synthesis was carried out in the presence of amino acids, mixed ligand complexes [Zn(L<sup>R</sup>)(aa)(H<sub>2</sub>O)]<sub>n</sub> (R = aa = Val, <b>2d</b>, and R = aa = Ile, <b>2e</b>) were formed. Complexes <b>2d</b>–<b>2e</b> were also structurally characterized using single-crystal X-ray crystallography, revealing that the ligand [L<sup>R</sup>]<sup>−</sup> maintained the same coordination mode, while the zinc center adopted a five-coordinated geometry. The cytotoxic activity of complexes <b>2a</b>–<b>2e</b> was evaluated against three cancer cell lines and one non-cancerous cell line. Remarkably, these complexes exhibited higher toxicity against cancer cells than against the non-cancerous cell line, and they showed greater selectivity than carboplatin, a commonly used chemotherapy drug. Although, in general, these complexes did not surpass the selectivity of gemcitabine, complex <b>2c</b> stood out for exhibiting a selectivity index value similar to that of gemcitabine against melanoma cells. Among the series, compounds <b>2a</b>–<b>2c</b> demonstrated the highest activity, with <b>2a</b> being the only complex with some selective activity against lung cancer. Complex <b>2b</b> was the most active, though with low selectivity, while complex <b>2c</b> exhibited the highest selectivity for melanoma and bladder cancer (selectivity index of 3.0).