Influence of the pendant arm in deoxydehydration catalyzed by dioxomolybdenum complexes supported by amine bisphenolate ligands

Abstract

Molybdenum complexes devoid of a strongly coordinating pendant arm result in enhanced catalytic activity.

Titania-supported molybdenum oxide combined with Au nanoparticles as a hydrogen-driven deoxydehydration catalyst of diol compounds

“…48 Another study by John et al showed that a dimeric μ-oxobis(dioxomolybdenum) complex with an amine phenolate ligand showed similar catalytic activity in the DODH reaction to monomeric dioxomolybdenum complexes. 47 Heptamolybdate (Mo 7 O 26 4− ), a polynuclear Mo species with μ-oxo connections, has been confirmed as an effective DODH catalyst or a pre-catalyst by several research groups. 49,50,52 Nicholas et al reported that the TOF values of MoO x catalysts supported on various conventional supports are similar in the DODH reaction with triphenylphosphine as a reducing agent, while the oligomerization degree of MoO x species was different among supports.…”

“…30 In fact, Mo and Re play a similar role in various catalysts for oxygen removal reactions, for example, sulfidetype catalysts, 31 Rh-MO x /SiO 2 , [32][33][34][35] Rh-MO x /C, [36][37][38] Ir-MO x / SiO 2 , [39][40][41] and Pt-MO x /TiO 2 (M = Re or Mo). 42,43 Several homogeneous Mo-based DODH catalysts have been reported such as MoO 2 (acac) 2 , 44 Mo-bisphenolate, [45][46][47] Mo-Cp* complex, 48 and ammonium heptamolybdate tetrahydrate, [49][50][51] although the activity and selectivity are generally inferior to those of Re-based ones. Palkovits et al reported MoO x /TiO 2 in combination with 3-octanol as a reducing agent as the first non-Re-based heterogeneous DODH catalyst system that can give good yields of DODH products.…”

Substituent Controlled Synthesis of Dioxidomolybdenum(VI) Complexes of N,N,N’,N’‐Tetrakis(2‐Hydroxyl‐3,5‐Disubstitutedbenzyl)‐1,2‐Diaminoethane, Their Trans‐Metalation to Oxidovanadium(V) Complexes and Biocatalytic Applications

“…Oxygen atom transfer (OAT) is also well studied reaction by model molybdenum complexes having a cis‐[Mo VI O 2 ] core [5–15] . Such molybdenum complexes also play an important role in a bioinspired catalytic oxidative bromination of organic substrates, [16] oxidation [17–19] and deoxydehydration of alcohols, [18] olefin epoxidation/sulfoxidation, [20,21] hydrosilylation, [22] and multicomponent one pot reaction (MCR) [23]…”

“…[4] Oxygen atom transfer (OAT) is also well studied reaction by model molybdenum complexes having a cis-[Mo VI O 2 ] core. [5][6][7][8][9][10][11][12][13][14][15] Such molybdenum complexes also play an important role in a bioinspired catalytic oxidative bromination of organic substrates, [16] oxidation [17][18][19] and deoxydehydration of alcohols, [18] olefin epoxidation/ sulfoxidation, [20,21] hydrosilylation, [22] and multicomponent one pot reaction (MCR). [23] Apart from molybdenum complexes with Schiff base ligands, which are extensively reported over the decades, several papers appeared on the mononuclear cis-[Mo VI O 2 ] complexes of N-capped (tridentate) and N,N'-capped (tetradentate)aminophenolates which are easily synthesized by a one-pot Mannich condensation between readily available primary or secondary amines, formaldehyde and substituted phenols.…”

Recent Progress with Pincer Transition Metal Catalysts for Sustainability

“…The reaction proceeds in the presence of a sacrificial reducing agent and results in the formation of alkenes, relevant building blocks for the polymer industry. Some examples using pincer ligation are reported with vanadium [106,107], rhenium [158], as well as molybdenum pincer catalysts [159]. The field is relatively immature and further optimization is necessary.…”