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Use of organomolybdenum compounds for promoted hydrolysis of phosphoester bonds in aqueous media

Publication . Gamelas ou Carla A. Gamelas, Carla; Gomes, Ana C.; Fernandes, José A.; Paz, Filipe A. Almeida; Nunes, Patrique; Pillinger, Martyn; Gonçalves, Isabel S.; Romão, Carlos C.; Abrantes, Marta

2016-09Conference object

Open access

Application of an Indenyl Molybdenum Dicarbonyl Complex in the Isomerisation of α-Pinene Oxide to Campholenic Aldehyde

Publication . Bruno, S.; Gomes, A. C.; Gamelas ou Carla A. Gamelas, Carla; Abrantes, M.; Oliveira, M. C.; Valente, A.; Almeida-Paz, Filipe; Pillinger, M.; Romão, C.; Gonçalves, I.

The complex [{(Z5-Ind)Mo(CO)2(m-Cl)}2] (1) has been tested for the industrially relevant catalytic isomerisation of a-pinene oxide (PinOx) to campholenic aldehyde (CPA) in the liquid phase. PinOx conversion and CPA selectivity are strongly influenced by the solvent employed. Complete conversion of PinOx was achieved within 1 min at 55 1C or 30 min at 35 1C using 1,2-dichloroethane as solvent, giving CPA in 68% yield. Other products included trans-carveol, iso-pinocamphone and trans-pinocarveol. The stability of 1 under the reaction conditions used was investigated by using FT-IR spectroscopy and electrospray ionisation mass spectrometry (ESI-MS) to characterise recovered solids. In the presence of air/moisture 1 undergoes oxidative decarbonylation upon dissolution to give oxomolybdenum species that are proposed to include a tetranuclear oxomolybdenum(V) complex. Conversely, ESI-MS studies of 1 dissolved in dry acetonitrile show mononuclear species of the type [IndMo(CO)2(CH3CN)n]+. The crystal structure of the ring-slipped dicarbonyl complex [(Z3-Ind)Mo(CO)2Cl(CH3CN)2] (2) (obtained after dissolution of 1 in acetonitrile) is reported.

2013Journal article

Restricted access

Use of organomolybdenum compounds for promoted hydrolysis of phosphoester bonds in aqueous media

Publication . Gomes, A.; Gamelas ou Carla A. Gamelas, Carla; Fernandes, J.; Almeida-Paz, F.; Nunes, P.; Pillinger, M.; Gonçalves, I.; Romão, C.; Abrantes, M.

The dissolution of the indenyl (Ind) complex [{(η5‐Ind)Mo(CO)2(μ‐Cl)}2] (1) in N,N′‐dimethylformamide (DMF) gives the ring‐slipped complex [(η3‐Ind)Mo(CO)2Cl(DMF)2] (2). The aerial oxidation of 2 leads to the formation of the dinuclear oxomolybdenum(V) chloride [Mo2O2(DMF)4(μ‐O)2Cl2] (3). The structures of 2 and 3·DMF have been determined by single‐crystal X‐ray diffraction. Compounds 1 and 3 were examined as promoters of phosphoester bond hydrolysis in para‐nitrophenylphosphate (pNPP), which was used as a model substrate. The reactions were performed in aqueous solution at 55 °C and followed by 1H NMR spectroscopy. For assays performed with 30–100 mol‐% of 1 or 3 relative to pNPP, both compounds promote the production of para‐nitrophenol (pNPh) from pNPP. Compound 3 is especially active in promoting the hydrolytic cleavage of the phosphoester bond (t1/2 < 80 min).

2014Journal article

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