resumo
The complex (Htrz)(2)[Mo3O6(O-2)(4)(trz)(2)]center dot H2O (1), isolated from the reaction of MoO3 with H2O2 in the presence of 1,2,4-triazole (trz), displays singular structural features such as double bridges comprising one oxido and one triazole ligand, and peripheral oxidodiperoxido-molybdenum(VI) units. A comparative study was performed regarding the catalytic activity and stability of complex1 and the hybrid material [MoO3(trz)(0.5)] (2) for the epoxidation of cis-cyclooctene (Cy8), the alcoholysis of epoxides, and the acetalization of benzaldehyde (PhCHO). Methanol or ethanol were used as solvents and reagents for the latter two reactions. For the substrates Cy8, styrene oxide, and PhCHO, the corresponding epoxide, beta-alkoxy alcohol, and dialkyl acetal were obtained with 100% selectivity at very high conversions. In general, 1 performed better than 2 for the different catalytic reactions. Under certain oxidant/co-solvent conditions used for Cy8 epoxidation, 1 was converted to 2 during the reaction.
palavras-chave
HYDROGEN-PEROXIDE; ETA(2)-PYRAZOLATE LIGANDS; CRYSTAL-STRUCTURE; MOLYBDENUM; HYBRIDS; ACID; OXO; CYCLOHEXENE; DERIVATIVES; VOLATILITY
categoria
Chemistry
autores
Antunes, MM; Amarante, TR; Valente, AA; Paz, FAA; Goncalves, IS; Pillinger, M
nossos autores
Anabela Tavares Aguiar Valente
Investigador Principal
Filipe Alexandre Almeida Paz
Investigador Principal
Isabel Maria de Sousa Gonçalves
Professor associado
Maria Margarida Feitor Pintão Moreno Antunes
Investigador Júnior
Martyn Pillinger
Investigador Principal
Tatiana Ribau Amarante
Investigador Júnioragradecimentos
This work was developed in the scope of the project (Associate Laboratory) CICECO-Aveiro Institute of Materials-POCI-01-0145-FEDER-007679 [FCT (Fundacao para a Ciencia e a Tecnologia) ref. UID/CTM/50011/2013], financed by national funds through the FCT/MEC and when applicable co-financed by FEDER (Fundo Europeu de Desenvolvimento Regional) under the PT2020 Partnership Agreement. The FCT and the European Union are acknowledged for post-doctoral grants to M.M.A. (SFRH/BPD/89068/2012) and T.R.A. (SFRH/BPD/97660/2013), co-funded by MCTES and the European Social Fund through the program POPH of QREN.