resumo
A family of molybdenum(VI) oxide hybrid solids with the general compositions [MoO3(tr)], [Mo2O6(tr)] and [Mo2O6(tr)(H2O)(2)] (tr = 1,2,4-triazole ligands bearing amine, pyrazole, 1H-tetrazole, and 1,2,4-triazole groups) have been shown to promote the epoxidation of cis-cyclooctene, the oxidative dehydrogenation of benzyl alcohol to give benzaldehyde, and the oxidation of benzaldehyde to give benzoic acid, using aqueous H2O2 as oxidant. All materials studied act as pre-catalysts and undergo chemical transformation in the presence of the oxidant to give the active oxidising species which, on the basis of characterisation data for recovered compounds, are either mononuclear or polynuclear oxo(peroxo)molybdenum(VI) complexes. Materials with one-dimensional (1D) structures led to homogeneous catalytic reactions with activities that were generally superior to those obtained with materials possessing more rigid 2D/3D structures containing bitriazole ligands. The latter were proposed to lead to interconverting mononuclear (poorly soluble) and dinuclear (soluble) species of the type [MoO(O-2)(2)(L)] and [{MoO(O-2)(2)(L)}(2)(mu-O)].
palavras-chave
SELF-SEPARATING CATALYSTS; OLEFIN EPOXIDATION; HYDROTHERMAL SYNTHESIS; CRYSTAL-STRUCTURE; BENZYL ALCOHOL; CYCLOOCTENE EPOXIDATION; MOLECULAR MANIPULATION; MOLYBDENUM OXIDES; COMPLEXES; BENZALDEHYDE
categoria
Chemistry
autores
Neves, P; Lysenko, AB; Gomes, AC; Pillinger, M; Goncalves, IS; Valente, AA
nossos autores
Ana Catarina Costa Gomes Alves
Investigador Auxiliar
Anabela Tavares Aguiar Valente
Investigador Principal
Isabel Maria de Sousa Gonçalves
Professor associado
Martyn Pillinger
Investigador Principal
Patrícia dos Santos Neves
Investigador Auxiliaragradecimentos
This work was developed in the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145FEDER-007679 [FCT (Fundacao para a Cincia 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 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.