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Oxidoperoxidomolybdenum(vi) complexes with acylpyrazolonate ligands: synthesis, structure and catalytic properties.
- Source :
- Dalton Transactions: An International Journal of Inorganic Chemistry; 1/7/2018, Vol. 47 Issue 1, p197-208, 12p
- Publication Year :
- 2018
-
Abstract
- Oxidoperoxido–molybdenum(vi) complexes containing acylpyrazolonate ligands were obtained by reaction of [Mo(O)(O)<subscript>2</subscript>(H<subscript>2</subscript>O)<subscript>n</subscript>] with the corresponding acylpyrazolone compounds HQ<superscript>R</superscript>. Complexes Ph<subscript>4</subscript>P[Mo(O)(O<subscript>2</subscript>)<subscript>2</subscript>(Q<superscript>R</superscript>)] (R = neopentyl, 1; perfluoroethyl, 2; hexyl, 3; phenyl, 4; naphthyl, 5; methyl, 6; cyclohexyl, 7; ethylcyclopentyl, 8) were obtained if the reaction was carried out with one equivalent of HQ<superscript>R</superscript> in the presence of Ph<subscript>4</subscript>PCl. Alternatively, neutral complexes [Mo(O)(O<subscript>2</subscript>)(Q<superscript>R</superscript>)<subscript>2</subscript>] (R = neopentyl, 9; hexyl, 10; cyclohexyl, 11) were formed when two equivalents of HQ<superscript>R</superscript> were used in the reaction. These complexes were isolated in good yields as yellow or yellow-orange crystalline solids and were spectroscopically (IR, <superscript>1</superscript>H, <superscript>13</superscript>C{<superscript>1</superscript>H} and <superscript>31</superscript>P{<superscript>1</superscript>H} NMR), theoretically (DFT) and structurally characterised (X-ray for 1, 2, 9 and 10). Compounds 1 and 9 were selected to investigate their catalytic behaviour in epoxidation of selected alkenes and oxidation of selected sulphides, while 10 and 11 were tested as catalyst precursors in the deoxygenation of selected epoxide substrates to alkenes, using PPh<subscript>3</subscript> as the oxygen-acceptor. Complexes Ph<subscript>4</subscript>P[Mo(O)(O<subscript>2</subscript>)<subscript>2</subscript>(Q<superscript>R</superscript>)] were shown to be poor catalyst precursors in oxidation reactions, while the activity of [Mo(O)(O<subscript>2</subscript>)(Q<superscript>R</superscript>)<subscript>2</subscript>] species is good in all the studied reactions and comparable to related oxidoperoxido–molybdenum(vi) complexes. Complex [Mo(O)<subscript>2</subscript>(Q<superscript>C6</superscript>)<subscript>2</subscript>], 12, was obtained by treatment of 10 with one equivalent of PPh<subscript>3</subscript>, demonstrating that the first step in the epoxide deoxygenation mechanism was the oxygen atom transfer toward the phosphane. [ABSTRACT FROM AUTHOR]
- Subjects :
- MOLYBDENUM compounds synthesis
PYRAZOLE derivatives
METAL complexes
Subjects
Details
- Language :
- English
- ISSN :
- 14779226
- Volume :
- 47
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Dalton Transactions: An International Journal of Inorganic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 126844118
- Full Text :
- https://doi.org/10.1039/c7dt03939e