Jump to main content
Jump to site search

Issue 31, 2015
Previous Article Next Article

Dichlorodioxomolybdenum(VI) complexes bearing oxygen-donor ligands as olefin epoxidation catalysts

Author affiliations

Abstract

Treatment of the solvent adduct [MoO2Cl2(THF)2] with either 2 equivalents of N,N-dimethylbenzamide (DMB) or 1 equivalent of N,N′-diethyloxamide (DEO) gave the dioxomolybdenum(VI) complexes [MoO2Cl2(DMB)2] (1) and [MoO2Cl2(DEO)] (2). The molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction. Both complexes present a distorted octahedral geometry and adopt the cis-oxo, trans-Cl, cis-L configuration typical of complexes of the type [MoO2X2(L)n], with either the monodentate DMB or bidentate DEO oxygen-donor ligands occupying the equatorial positions trans to the oxo groups. The complexes were applied as homogeneous catalysts for the epoxidation of olefins, namely cis-cyclooctene (Cy), 1-octene, trans-2-octene, α-pinene and (R)-(+)-limonene, using tert-butylhydroperoxide (TBHP) as oxidant. In the epoxidation of Cy at 55 °C, the desired epoxide was the only product and turnover frequencies in the range of ca. 3150–3200 mol molMo−1 h−1 could be reached. The catalytic production of cyclooctene oxide was investigated in detail, varying either the reaction temperature or the cosolvent. Complexes 1 and 2 were also applied in liquid–liquid biphasic catalytic epoxidation reactions by using an ionic liquid of the type [C4mim][X] (C4mim = 1-n-butyl-3-methylimidazolium; X = NTf2, BF4 or PF6] as a solvent to immobilise the metal catalysts. Recycling for multiple catalytic runs was achieved without loss of activity.

Graphical abstract: Dichlorodioxomolybdenum(vi) complexes bearing oxygen-donor ligands as olefin epoxidation catalysts

Back to tab navigation

Supplementary files

Publication details

The article was received on 08 Jun 2015, accepted on 29 Jun 2015 and first published on 07 Jul 2015


Article type: Paper
DOI: 10.1039/C5DT02165K
Citation: Dalton Trans., 2015,44, 14139-14148
  •   Request permissions

    Dichlorodioxomolybdenum(VI) complexes bearing oxygen-donor ligands as olefin epoxidation catalysts

    T. S. M. Oliveira, A. C. Gomes, A. D. Lopes, J. P. Lourenço, F. A. Almeida Paz, M. Pillinger and I. S. Gonçalves, Dalton Trans., 2015, 44, 14139
    DOI: 10.1039/C5DT02165K

Search articles by author

Spotlight

Advertisements