New palladium(ii ) complexes with 3-(2-pyridyl)-5-alkyl-1,2,4-triazole ligands as recyclable C–C coupling catalysts
| Autor: | Olga V. Severynovska, Ilona V. Raspertova, Sergiu Shova, Volodymyr V. Trachevsky, Viktoriia S. Starova, Armando J. L. Pombeiro, Vladimir B. Arion, Rostyslav D. Lampeka, Borys V. Zakharchenko, Dmytro M. Khomenko, Luísa M. D. R. S. Martins, Roman O. Doroshchuk |
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| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
Chemistry Hydrogen bond chemistry.chemical_element 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Medicinal chemistry Catalysis 0104 chemical sciences chemistry.chemical_compound Bromoanisole Materials Chemistry Nitroethane 0210 nano-technology Boronic acid Alkyl Coordination geometry Palladium |
| Zdroj: | New Journal of Chemistry. 43:10973-10984 |
| ISSN: | 1369-9261 1144-0546 |
| DOI: | 10.1039/c9nj02278c |
| Popis: | A series of palladium(II) complexes with 3-(2-pyridyl)-5R-1,2,4-triazoles Pd(LR)2 (R = ethyl (4a), n-propyl (4b), i-propyl (4c) and t-butyl (4d)) have been synthesised and characterised by NMR, IR, UV-vis spectroscopy, ESI and MALDI-TOF mass spectrometry. Single-crystal X-ray diffraction study of 4a–d revealed a square-planar coordination geometry, in which the N^N chelating monoanionic ligands adopt a trans-configuration around Pd(II) and show notable intraligand C–H⋯N hydrogen bonding within the complex. The solid state emission and excitation spectra of 4a–d showed vibronic structure of the spectra at room temperature. The TG/DTA curves of 4a–c revealed that the complexes are stable up to ca. 250 °C, whereas 4d starts to decompose at 230 °C. Compounds 4a–d efficiently catalyse the nitroaldol (Henry) reaction of benzaldehyde with nitroethane in water, methanol and ethanol with appreciable diastereoselectivity in favour of the syn-isomer (syn : anti up to 81 : 19). In addition, 4a–d catalyse the microwave-assisted Suzuki–Miyaura cross-coupling reaction of bromoanisole with phenyl boronic acid, in the presence of a base. Moreover, these heterogeneous catalysts can be recovered and reused without losing activity for several consecutive cycles. |
| Databáze: | OpenAIRE |
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