Synthesis and structural characterization of rhenium(I) tricarbonyl complexes with 2,6-bis(pyrazol-1-yl)pyridine ligands functionalized with carboxyl (-COOH), methoxycarbonyl (-COOCH3), and amino (-NH2) groups
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Issued Date
2026-03-01
Resource Type
ISSN
02775387
Scopus ID
2-s2.0-105027977209
Journal Title
Polyhedron
Volume
287
Rights Holder(s)
SCOPUS
Bibliographic Citation
Polyhedron Vol.287 (2026)
Suggested Citation
Temnuch N., Poonsawat T., Tanyalax T., Chumkaeo P., Chantarojsiri T., Chakarawet K., Yakiyama Y., Sakurai H., Somsook E. Synthesis and structural characterization of rhenium(I) tricarbonyl complexes with 2,6-bis(pyrazol-1-yl)pyridine ligands functionalized with carboxyl (-COOH), methoxycarbonyl (-COOCH3), and amino (-NH2) groups. Polyhedron Vol.287 (2026). doi:10.1016/j.poly.2026.117971 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/114711
Title
Synthesis and structural characterization of rhenium(I) tricarbonyl complexes with 2,6-bis(pyrazol-1-yl)pyridine ligands functionalized with carboxyl (-COOH), methoxycarbonyl (-COOCH3), and amino (-NH2) groups
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Abstract
Rhenium(I) tricarbonyl complexes with 2,6-bis(pyrazol-1-yl)pyridine ligands functionalized with -COOH, -COOCH<inf>3</inf>, and -NH<inf>2</inf> were synthesized via UV-induced substitution of Re(CO)<inf>5</inf>Br in acetone under 365 nm irradiation. Single-crystal X-ray diffraction revealed distorted octahedral geometries, with Re-N bond lengths of 2.133–2.239 Å, N-Re-N angles of 73.30–73.98°, and Re-Br distances of 2.627–2.642 Å, reflecting the influence of ligand substituents. ATR-IR spectroscopy demonstrated that electron-withdrawing -COOH and -COOCH<inf>3</inf> groups caused slight blue shifts in ν(CO), whereas -NH<inf>2</inf> induced red shifts, consistent with modulation of metal-to-ligand backbonding. UV–Vis studies showed that acetone preserved complex stability, whereas acetonitrile caused significant destabilization. Variable-temperature <sup>1</sup>H/<sup>13</sup>C NMR confirmed stable bidentate coordination in solution. DFT calculations revealed that electron-withdrawing groups lowered LUMO energies, while electron-donating group raised HOMO levels, tuning charge-transfer behavior. ESI-MS and elemental analyses confirmed molecular purity. These results indicate that functionalization of ligands enables precise control over rhenium(I) structural and electronic properties.