676-96-0Relevant articles and documents
Effects of Lewis Acidic Metal Ions (M) on Oxygen-Atom Transfer Reactivity of Heterometallic Mn3MO4 Cubane and Fe3MO(OH) and Mn3MO(OH) Clusters
Lionetti, Davide,Suseno, Sandy,Tsui, Emily Y.,Lu, Luo,Stich, Troy A.,Carsch, Kurtis M.,Nielsen, Robert J.,Goddard, William A.,Britt, R. David,Agapie, Theodor
, p. 2336 - 2345 (2019)
The modulation of the reactivity of metal oxo species by redox inactive metals has attracted much interest due to the observation of redox inactive metal effects on processes involving electron transfer both in nature (the oxygen-evolving complex of Photosystem II) and in heterogeneous catalysis (mixed-metal oxides). Studies of small-molecule models of these systems have revealed numerous instances of effects of redox inactive metals on electron- and group-transfer reactivity. However, the heterometallic species directly involved in these transformations have rarely been structurally characterized and are often generated in situ. We have previously reported the preparation and structural characterization of multiple series of heterometallic clusters based on Mn3 and Fe3 cores and described the effects of Lewis acidity of the heterometal incorporated in these complexes on cluster reduction potential. To determine the effects of Lewis acidity of redox inactive metals on group transfer reactivity in structurally well-defined complexes, we studied [Mn3MO4], [Mn3MO(OH)], and [Fe3MO(OH)] clusters in oxygen atom transfer (OAT) reactions with phosphine substrates. The qualitative rate of OAT correlates with the Lewis acidity of the redox inactive metal, confirming that Lewis acidic metal centers can affect the chemical reactivity of metal oxo species by modulating cluster electronics.
Oxido- versus imido-transfer reactions in oxido-imido molybdenum(VI) complexes: A combined experimental and theoretical study
Pastor, Antonio,Montilla, Francisco,Galindo, Agustín
, p. 233 - 238 (2015)
The reaction of the oxido-imido molybdenum(VI) compounds [Mo(O)(Nmes)(S2CNR2)2] (mes = 2,4,6-C6H2Me3, R2 = iPr2, 1a; C4H4, 1b) with an excess of PMe3 was investigated. [Mo(Nmes)(S2CNR2)2(PMe3)] (R2 = iPr2, 2a; C4H4, 2b) complexes and the corresponding phosphane oxide OPMe3 were exclusively detected as reaction products, according to an oxygen atom transfer (OAT) reaction. No evidence of the possible imido transfer reaction was observed. In order to explain the selective OAT reaction in this system, DFT calculations were carried out with the model compound [Mo(O)(N-2,6-Me2C6H3)(S2CNMe2)2], 1c, and PMe3 as reactant. The two possible oxido transfer and imido transfer pathways were considered and the nucleophilic attack of the phosphane to the multiple bonded atom was the associative intermolecular processes modelled. The oxido transfer is thermodynamic and kinetically favoured with respect the imido one in agreement with the experimental results.
Degradation of Organic Cations under Alkaline Conditions
You, Wei,Hugar, Kristina M.,Selhorst, Ryan C.,Treichel, Megan,Peltier, Cheyenne R.,Noonan, Kevin J. T.,Coates, Geoffrey W.
supporting information, p. 254 - 263 (2020/12/23)
Understanding the degradation mechanisms of organic cations under basic conditions is extremely important for the development of durable alkaline energy conversion devices. Cations are key functional groups in alkaline anion exchange membranes (AAEMs), and AAEMs are critical components to conduct hydroxide anions in alkaline fuel cells. Previously, we have established a standard protocol to evaluate cation alkaline stability within KOH/CD3OH solution at 80 °C. Herein, we are using the protocol to compare 26 model compounds, including benzylammonium, tetraalkylammonium, spirocyclicammonium, imidazolium, benzimidazolium, triazolium, pyridinium, guanidinium, and phosphonium cations. The goal is not only to evaluate their degradation rate, but also to identify their degradation pathways and lead to the advancement of cations with improved alkaline stabilities.
Dioxygen activation with molybdenum complexes bearing amide-functionalized iminophenolate ligands
Zwettler, Niklas,Ehweiner, Madeleine A.,Schachner, J?rg A.,Dupé, Antoine,Belaj, Ferdinand,M?sch-Zanetti, Nadia C.
, (2019/05/24)
Two novel iminophenolate ligands with amidopropyl side chains (HL2 and HL3) on the imine functionality have been synthesized in order to prepare dioxidomolybdenum(VI) complexes of the general structure [MoO2L2] featuring pendant internal hydrogen bond donors. For reasons of comparison, a previously published complex featuring n-butyl side chains (L1) was included in the investigation. Three complexes (1-3) obtained using these ligands (HL1-HL3) were able to activate dioxygen in an in situ approach: The intermediate molybdenum(IV) species [MoO(PMe3)L2] is first generated by treatment with an excess of PMe3. Subsequent reaction with dioxygen leads to oxido peroxido complexes of the structure [MoO(O2)L2]. For the complex employing the ligand with the n-butyl side chain, the isolation of the oxidomolybdenum(IV) phosphino complex [MoO(PMe3)(L1) 2] (4) was successful, whereas the respective Mo(IV) species employing the ligands with the amidopropyl side chains were found to be not stable enough to be isolated. The three oxido peroxido complexes of the structure [MoO(O2)L2] (9-11) were systematically compared to assess the influence of internal hydrogen bonds on the geometry as well as the catalytic activity in aerobic oxidation. All complexes were characterized by spectroscopic means. Furthermore, molecular structures were determined by single-crystal X-ray diffraction analyses of HL3, 1-3, 9-11 together with three polynuclear products {[MoO(L2) 2]2 (μ-O)} (7), {[MoO(L2)] 4 (μ-O) 6} (8) and [C9H13N2O]4 [Mo8O26] 6OPMe3 (12) which were obtained during the synthesis of reduced complexes of the type [MoO(PMe3)L2] (4-6).
