authors |
Nogueira, LS; Neves, P; Gomes, AC; Lavrador, P; Cunha-Silva, L; Valente, AA; Goncalves, IS; Pillinger, M |
nationality |
International |
journal |
RSC ADVANCES |
keywords |
CARBONYL-COMPLEXES; HYDROGEN-PEROXIDE; DERIVATIVES; TUNGSTEN; REACTIVITY; MO; 1,10-PHENANTHROLINE; OCTAMOLYBDATE; PRECURSORS; REDUCTION |
abstract |
The synthesis of molybdenum(0) tricarbonyl and tetracarbonyl complexes of the form [Mo(CO)(3)(ptapzpy)Br] (1) and cis-[Mo(CO)(4)(ptapzpy)]Br (2) is reported, where ptapzpy = 2-(1-propyltrimethylammonium-3-pyrazolyl)pyridine. Preparation of these derivatives was accomplished either through thermal replacement of CO in Mo(CO)(6) (for 1) or substitution under milder conditions of piperidine ligands in the precursor cis-[Mo(CO)(4)(pip)(2)] (for 2). The crystal structures of the ligand [ptapzpy] Br and complexes 1 and 2 were determined. Thermal treatment of 2 at 125-150 degrees C leads to mono decarbonylation and formation of 1. On the other hand, oxidative decarbonylation of 1 and 2 by reaction with tert-butylhydroperoxide (TBHP, 10 equiv.) gives a molybdenum oxide hybrid material formulated as [Mo3O9([ptapzpy]Br)(2)]center dot nH(2)O (3), which was characterised by FT-IR and Raman spectroscopy, thermogravimetric analysis, and C-13{H-1} CP MAS NMR spectroscopy. Compounds 1-3 were effective (pre)catalysts for the epoxidation of cis-cyclooctene at 55 degrees C with aqueous H2O2 or TBHP (slightly better results were obtained with the former). The characterisation of the Mo-containing solids isolated after the catalytic reaction showed that poorly soluble beta-octamolybdate salts, (L)(x)[Mo8O26], were formed from 1-3 with TBHP and from 1 with H2O2, while soluble oxoperoxo species were formed from 3 with H2O2. These findings helped to explain the different catalytic performances obtained. |
publisher |
ROYAL SOC CHEMISTRY |
issn |
2046-2069 |
year published |
2018 |
volume |
8 |
issue |
29 |
beginning page |
16294 |
ending page |
16302 |
digital object identifier (doi) |
10.1039/c8ra01687a |
web of science category |
Chemistry, Multidisciplinary |
subject category |
Chemistry |
unique article identifier |
WOS:000431814200052
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ciceco authors
impact metrics
journal analysis (jcr 2019):
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journal impact factor |
3.119 |
5 year journal impact factor |
3.098 |
category normalized journal impact factor percentile |
59.04 |
dimensions (citation analysis):
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altmetrics (social interaction):
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