Speaker
Description
Due to the aromatic nature of the pyrazole ring, pyrazole derivatives are potentially applicable as luminescent materials, sensors, and functional materials. The flexible coordination behavior of Cd(II), combined with the tunable electronic properties of pyrazole-based ligands, enables the formation of different structures with attractive photophysical characteristics. In this work, a series of cadmium halide complexes (CdX₂, X = Cl, Br, I) with ethyl 5-amino-1-methyl-1H-pyrazole-4-carboxylate was synthesized under different reaction conditions and characterized by structural, spectroscopic, and thermal methods. Structural investigations revealed that the presence of water significantly affects the coordination environment of the Cd(II) centers and the resulting crystal structures, leading to the formation of different compounds from the same precursors. These moisture-induced differences demonstrate the sensitivity of the complexes to environmental conditions and highlight the role of water in the formation of the coordination compounds. Except for CdI2, synthesis with other halides yielded the coordination polymers, promising for light-harvesting applications. These findings contribute to a better understanding of the relationship between synthesis conditions, solid-state structure, and material properties, which is essential for the rational design of coordination compounds with tailored functionalities and potential applications in optical and advanced functional materials.
Acknowledgement: The authors gratefully acknowledge the financial support of the Ministry of Science, Technological Development and Innovation of the Republic of Serbia (Grants No. 451-03-33/2026-03/ 200125 & 451-03-34/2026-03/ 200125).
Keywords: pyrazole derivative, cadmium complex, moisture, structure.