TY - JOUR
T1 - Epoxidation of cis-cyclooctene using diamine bis(phenolate) vanadium, molybdenum and tungsten complexes as catalysts
AU - Madeira, Filipe
AU - Barroso, Sónia
AU - Namorado, Sónia
AU - Reis, Patricia M.
AU - Royo, Beatriz
AU - Martins, Ana Margarida
N1 - The authors thank the Portuguese NMR Network (IST-UTL Center) for providing access to the NMR facilities and the Fundacao para a Ciencia e Tecnologia for financial support (research projects PTDC/QUI/66187/2006 and PTDC/QUI/098682/2008 and fellowships SFRH/BD/13374/2003, SFRH/BP/20655/2004 and SFRH/BD/28762/2006).
PY - 2012/3/30
Y1 - 2012/3/30
N2 - The dioxomolybdenum and dioxotungsten complexes [MoO 2L 1] (1-Mo) and [WO 2L 1] (2-W), supported by a diamine bis(phenolate) ligand (L 1 = Me 2NCH 2CH 2N(CH 2-2-O-3,5-C 6H 2 tBu 2) 2) were prepared from MoO 2Cl 2 and WO 2Cl 2(dme) in good yields. The solid-state structures of both compounds obtained by single crystal X-ray diffraction reveal distorted octahedral geometries around the metals with cis terminal oxo ligands. Their performance in the catalytic epoxidation of cis-cyclooctene using H 2O 2 and TBHP as oxidants was evaluated. 2-W displays high activity with H 2O 2 as terminal oxidant, achieving 84% conversion in 6 h (TOF = 1400 mol sub mol cat -1 h -1), while its molybdenum counterpart 1-Mo was inactive in the same conditions. Using TBHP as oxidant the opposite trend was observed and 1-Mo attained 93% conversion in 6 h (TOF = 1550 mol sub mol cat -1 h -1). The Oxovanadium complexes [VOL 1Cl] (3-V), [VOL 2Cl] (4-V, L 2 = Me 2NCH 2CH(CH 3)N(CH 2-2-O-3,5-C 6H 2 tBu 2) 2) and [(VOL 1) 2(μ-O)] (5-V) were also tested as catalysts in the epoxidation of cis-cyclooctene. The three compounds display high activity when the epoxidation reaction is performed using TBHP as oxidant. Using H 2O 2, 3-V and 4-V are moderately active while 5-V is inactive.
AB - The dioxomolybdenum and dioxotungsten complexes [MoO 2L 1] (1-Mo) and [WO 2L 1] (2-W), supported by a diamine bis(phenolate) ligand (L 1 = Me 2NCH 2CH 2N(CH 2-2-O-3,5-C 6H 2 tBu 2) 2) were prepared from MoO 2Cl 2 and WO 2Cl 2(dme) in good yields. The solid-state structures of both compounds obtained by single crystal X-ray diffraction reveal distorted octahedral geometries around the metals with cis terminal oxo ligands. Their performance in the catalytic epoxidation of cis-cyclooctene using H 2O 2 and TBHP as oxidants was evaluated. 2-W displays high activity with H 2O 2 as terminal oxidant, achieving 84% conversion in 6 h (TOF = 1400 mol sub mol cat -1 h -1), while its molybdenum counterpart 1-Mo was inactive in the same conditions. Using TBHP as oxidant the opposite trend was observed and 1-Mo attained 93% conversion in 6 h (TOF = 1550 mol sub mol cat -1 h -1). The Oxovanadium complexes [VOL 1Cl] (3-V), [VOL 2Cl] (4-V, L 2 = Me 2NCH 2CH(CH 3)N(CH 2-2-O-3,5-C 6H 2 tBu 2) 2) and [(VOL 1) 2(μ-O)] (5-V) were also tested as catalysts in the epoxidation of cis-cyclooctene. The three compounds display high activity when the epoxidation reaction is performed using TBHP as oxidant. Using H 2O 2, 3-V and 4-V are moderately active while 5-V is inactive.
KW - Diamine bis(phenolate) complexes
KW - Epoxidation
KW - Molybdenum
KW - Tungsten
KW - Vanadium
UR - http://www.scopus.com/inward/record.url?scp=84857233764&partnerID=8YFLogxK
U2 - 10.1016/j.ica.2011.10.071
DO - 10.1016/j.ica.2011.10.071
M3 - Article
AN - SCOPUS:84857233764
SN - 0020-1693
VL - 383
SP - 152
EP - 156
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
ER -