resumo
Tetracarbonylmolybdenum(0) complexes of the type cis-[Mo(CO)(4)(L)] are attractive synthetic precursors of high oxidation state oxomolybdenum catalysts since the byproducts (CO/CO2) readily separate from the reaction mixture, facilitating separation/purification procedures (e.g. avoiding contamination/acidification of the medium for halide (X)-containing precursors such as [Mo(eta(3)-C3H5) Cl(CO)(2)(L)]). In this work, the conversion of the tetracarbonyl complex cis-[Mo(CO)(4)(ppp)] (ppp = 2-(1-pentyl-3-pyrazolyl) pyridine) to oxomolybdenum compounds has been studied. The molybdenum compounds prepared were explored for liquid phase oxidation and acid catalysis, specifically the epoxidation of cis-cyclooctene with hydroperoxide oxidants, and the alcoholysis of styrene oxide. The routes for the conversion of the cis-[Mo(CO)(4)(ppp)] precursor to oxomolybdenum compounds, during either the synthesis (ex situ) or catalytic (in situ) processes (involving isolation/characterisation of metal species after the catalytic runs), were studied for the different catalytic systems, which helped establish relationships between the type of metal species formed and the catalytic performance. Catalyst recyclability was investigated using a homogeneous catalytic ionic liquid-standing approach. (C) 2017 Elsevier B.V. All rights reserved.
palavras-chave
MOLYBDENUM(VI) COMPLEXES; OXIDATION; PRECURSORS; EFFICIENT; DERIVATIVES; MONONUCLEAR; LIGANDS; TRIS(3,5-DIMETHYL-1-PYRAZOLYL)METHANE; CYCLOOCTENE; REACTIVITY
categoria
Chemistry
autores
Nogueira, LS; Neves, P; Gomes, AC; Valente, AA; Pillinger, M; Goncalves, IS
nossos autores
Ana Catarina Costa Gomes Alves
Investigador Auxiliar
Anabela Tavares Aguiar Valente
Investigador Principal
Isabel Maria de Sousa Gonçalves
Professor associado
Lucie Solange Nogueira
Estudante de doutoramento
Martyn Pillinger
Investigador Principal
Patrícia dos Santos Neves
Investigador Auxiliaragradecimentos
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 a Ph.D. grant to L.N. (PD/BD/109666/2015), and post-doctoral grants to P.N. (SFRH/BPD/110530/2015) and A.C.G. (SFRH/BPD/108541/2015), co-funded by MCTES and the European Social Fund through the program POPH of QREN.