A density functional theory study of the mechanisms of oxidation of ethylene by rhenium oxide complexes

Aniagyei, Albert; Tia, Richard; Adei, Evans

doi:10.1039/c3dt50539a

Cited by 11 publications

(18 citation statements)

References 39 publications

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“…9 ) is highly competitive, with activation barrier of 1.05 kcal/mol. The formation of Co3 and Rh3 on all surfaces have lower activation barriers than the formation of Ir3 , a trend consistent in the works of Aniayei et al 2013a , b , c and Ahmed et al ( 2015a , b ) in the catalytic oxidation of olefins and ketenes respectively using group VII transition metal oxides. Again, the potential energy surfaces of the lower homologues have fewer competitive side reactions than those of the higher homologue, a similar trend was also noted in our earlier works (Aniayei et al 2013a , b , c ; Ahmed et al 2015a , b ) in the reactions of group VII metal complex with olefins and ketenes.…”

Section: Resultssupporting

confidence: 89%

“…It is found that for the reaction of the RhO 2 (CH 2 )(CH 3 ) complex, the [2 + 2] Rh,O is the most plausible pathway on the singlet PES, the [3 + 2] C,O is the most favoured pathway on the doublet surface, whiles the [2 + 2] Rh,C is the most plausible pathway on the triplet PES. Generally, the formation of similar analogues have lower activation barriers for the Rh complexes than for the Ir complexes on all the surfaces explored, a trend consistent in the works of Aniayei et al ( 2013a , b , c ) and Ahmed et al ( 2015a , b ) in the catalytic oxidation of olefins and ketenes respectively using group VII transition metal oxides.…”

Section: Resultssupporting

confidence: 88%

“…Density functional theory studies of the mechanisms of oxidation of ethylene by chromyl chloride had also been studied (Tia and Adei 2009 ; Torrent et al 1999 ) as well as the oxidation of ethylene by the group VII transition metal-oxo complexes of the type LMO 3 (M=Mn, Tc, Re and L=O–, Cl, CH 3 , OCH 3 , Cp) (Aniayei et al 2013a , b , c ). All these studies indicated that the [3 + 2] addition has a lower barrier than the [2 + 2] addition step in most cases on the singlet potential surface, but [2 + 2] addition was favoured in some cases especially on other PESs.…”

Section: Introductionmentioning

confidence: 99%

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A quantum chemical study of the mechanisms of olefin addition to group 9 transition metal dioxo compounds

2016

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The mechanistic aspects of ethylene addition to MO2(CH2)(CH3) (M=Co, Rh, Ir) have been investigated with a Hartree–Fock/DFT hybrid functional at the MO6/LACVP* and B3LYP/LACVP* levels of theory to elucidate the reaction pathways on the singlet, doublet and triplet potential energy surfaces (PES). In the reaction of the IrO2CH2CH3 complex with ethylene, [3 + 2]C,O addition is the most plausible pathway on the singlet PES, the [3 + 2]O,O addition is the most favoured pathway on the doublet surface whiles the stepwise [1 + 1] addition involving the oxygen atom of the complex in the first step and the carbon atom of the complex in the second step is the most plausible pathway on the triplet PES. For the reaction of the RhO2(CH2)(CH3) complex, the [2 + 2]Rh,O addition pathway is the most favoured on the singlet surface, the [2 + 2]Rh,C is the most plausible pathway on the triplet PES and [3 + 2]C,O is the most plausible on the doublet surface. For the reactions of the CoO2(CH2)(CH3) complex, the [1 + 2]O addition is the most plausible on the singlet PES, [3 + 2]C=Co=O cycloaddition to form the five–membered intermediate is the most preferred pathway on the doublet PES, whiles on the triplet PES the preferred pathway is the [3 + 2] addition across the O=Co=O bond of the metal complex. The reactions of olefins with the Co dioxo complex have lower activation barriers for the preferred [3 + 2] and [2 + 2] addition pathways as well as fewer side reactions than those of the rhodium and iridium systems. This could imply that the cobalt dioxo complexes can efficiently and selectively catalyze specific reactions in oxidation of olefins than Rh and Ir oxo complexes will do and therefore Co oxo complexes may be better catalysts for specific oxidation reactions of olefins than Rh and Ir complexes are. The activation barriers for the formation of the four—or five-membered metallacycle intermediates through [2 + 2] or [3 + 2] cyclo-addition are lower on the triplet PES than on the singlet PES for the formation of similar analogues. There are fewer competitive reaction pathways on the triplet surface than on the singlet PES. Also, cycloadditions that seem impossible on the singlet PES seem possible on the doublet and or triplet PESs, this is the case typically for the Rh and Co complexes, illustrating the importance of multiple spin states in organometallic reactions.Graphical AbstractTable of Contents Synopsis: A study of the mechanism of ethylene addition to MO2(CH2)(CH3)(M=Co,Rh,Ir) shows the reactions of the Co complex have lower activation barriers for the preferred [3+2] and [2+2] addition pathways and fewer side reactions than those of Rh and Ir. Reactions are more feasible and selective on the triplet PES than on the singlet PES. These illustrate the importance of multiple spin states in organometallic reactions and shows catalyst activity and selectivity decreases down the group.

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Section: Resultssupporting

confidence: 89%

Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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A quantum chemical study of the mechanisms of olefin addition to group 9 transition metal dioxo compounds

2016

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“…The mechanisms of the oxidation processes have been the subject of a lot of experimental and theoretical studies. [3][4][5][6][7][8][9][10][11] For the reaction of osmium tetraoxide (OsO 4 ) with olefins, Criegee et al, 12,13 proposed a concerted [3 + 2] cycloaddition pathway (path A * For correspondence in scheme 1). This proposal was widely accepted by organic chemists 4,14,15 partly due to the fact that it is analogous with other dipolar cycloadditions.…”

Section: Introductionmentioning

confidence: 99%

Quantum chemical study of the mechanisms of oxidation of ethylene by Molybdyl and Tungstyl Chloride

et al. 2016

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The mechanisms of oxidation of olefins with MoO 2 Cl 2 and WO 2 Cl 2 are studied with DFT. The formation of epoxide from these reactions is not very feasible by any of the postulated paths. If the epoxide precursor will form at all, it will arise via initial [3+2] O,Cl addition of ethene to MoO 2 Cl 2 and WO 2 Cl 2 to form an intermediate, followed by rearrangement to form the precursor, from which the epoxide can be generated by hydrolysis. The chlorohydrin precursor was also found to originate from [3+2] O,Cl addition of ethene to MO 2 Cl 2. The results also indicate that a dichloride is not a likely product in the oxidation of ethylene by molybdyl chloride. However, in the case of WO 2 Cl 2 , the formation of a dichloride may not be precluded. The formation of acetaldehyde and vinyl alcohol from the oxidation of ethylene does not appear energetically feasible with MoO 2 Cl 2 , but appears thermodynamically plausible with WO 2 Cl 2. Thus, the oxidation of ethylene with MoO 2 Cl 2 will most likely lead to the formation of chlorohydrins predominantly via [3+2] O,Cl addition; oxidation with WO 2 Cl 2 may also form chlorohydrins, but only extremely slowly. The oxyhalides MO 2 Cl 2 become weaker oxidants in the order CrO 2 Cl 2 >>MoO 2 Cl2>WO 2 Cl 2. Corresponding to this, reactions involving reduction of the metal [3 + 2] and [2+1] show a sharp increase in barrier going from Cr to W; reactions without a change in metal oxidation state ([2 + 2]) show much smaller variations, which are possibly mainly determined by sterics.

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“…In contrast to ketenes, experimental and theoretical investigations on the mechanism of addition of transition metal-oxide of the type LMO 3 (M = Mn, Tc and Re) across the C=C double bonds of olefins has been extensively reported (Sharpless and Akashi 1975 ; Wiberg 1965 ; Aniagyei et al 2013a , b , c ; Tia and Adei 2009 , 2011 ; Nelson et al 1997 ; Corey and Noe 1997 ; Haller et al 1997 ; Houk and Strassner 1999 ; Torrent et al 1998 ; Del Monte et al 1997 ; Tia and Adei 2011 ; Pietsch et al 1998 ; Deubel and Frenking 1999 ; Gisdakis and Rösch 2001 ). Ketenes are related to olefins by the presence of the C=C double bonds but ketenes constitute activated double bonds due to the presence of the C=O double bond directly bonded to the C=C double bond.…”

Section: Introductionmentioning

confidence: 99%

A computational study of the addition of ReO3L (L = Cl−, CH3, OCH3 and Cp) to ethenone

2016

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The periselectivity and chemoselectivity of the addition of transition metal oxides of the type ReO3L (L = Cl, CH3, OCH3 and Cp) to ethenone have been explored at the MO6 and B3LYP/LACVP* levels of theory. The activation barriers and reaction energies for the stepwise and concerted addition pathways involving multiple spin states have been computed. In the reaction of ReO3L (L = Cl−, OCH3, CH3 and Cp) with ethenone, the concerted [2 + 2] addition of the metal oxide across the C=C and C=O double bond to form either metalla-2-oxetane-3-one or metalla-2,4-dioxolane is the most kinetically favored over the formation of metalla-2,5-dioxolane-3-one from the direct [3 + 2] addition pathway. The trends in activation and reaction energies for the formation of metalla-2-oxetane-3-one and metalla-2,4-dioxolane are Cp < Cl− < OCH3 < CH3 and Cp < OCH3 < CH3 < Cl− and for the reaction energies are Cp < OCH3 < Cl− < CH3 and Cp < CH3 < OCH3 < Cl CH3. The concerted [3 + 2] addition of the metal oxide across the C=C double of the ethenone to form species metalla-2,5-dioxolane-3-one is thermodynamically the most favored for the ligand L = Cp. The direct [2 + 2] addition pathways leading to the formations of metalla-2-oxetane-3-one and metalla-2,4-dioxolane is thermodynamically the most favored for the ligands L = OCH3 and Cl−. The difference between the calculated [2 + 2] activation barriers for the addition of the metal oxide LReO3 across the C=C and C=O functionalities of ethenone are small except for the case of L = Cl− and OCH3. The rearrangement of the metalla-2-oxetane-3-one–metalla-2,5-dioxolane-3-one even though feasible, are unfavorable due to high activation energies of their rate-determining steps. For the rearrangement of the metalla-2-oxetane-3-one to metalla-2,5-dioxolane-3-one, the trends in activation barriers is found to follow the order OCH3 < Cl− < CH3 < Cp. The trends in the activation energies for the most favorable [2 + 2] addition pathways for the LReO3–ethenone system is CH3 > CH3O− > Cl− > Cp. For the analogous ethylene–LReO3 system, the trends in activation and reaction energies for the most favorable [3 + 2] addition pathway is CH3 > CH3O− > Cl− > Cp [10]. Even though the most favored pathway in the ethylene-LReO3 system is the [3 + 2] addition pathway and that on the LReO3–ethenone is the [2 + 2] addition pathway, the trends in the activation energies for both pathways are the same, i.e. CH3 > CH3O− > Cl− > Cp. However, the trends in reaction energies are quite different due to different product stabilities. The formation of the acetic acid precursor through the direct addition pathways was unsuccessful for all the ligands studied. The formation of the acetic acid precursor through the cyclization of the metalla-2-oxetane-3-one is only possible for the ligands L = Cl−, CH3 whiles for the cyclization of metalla-2-oxetane-4-one to the acetic acid precursor is only possible for the ligand L = CH3. Although there are spin-crossover reaction observed for the ligands L = Cl−, CH3 and CH3O−, the reactions occur...

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A density functional theory study of the mechanisms of oxidation of ethylene by rhenium oxide complexes

Cited by 11 publications

References 39 publications

A quantum chemical study of the mechanisms of olefin addition to group 9 transition metal dioxo compounds

A quantum chemical study of the mechanisms of olefin addition to group 9 transition metal dioxo compounds

Quantum chemical study of the mechanisms of oxidation of ethylene by Molybdyl and Tungstyl Chloride

A computational study of the addition of ReO3L (L = Cl−, CH3, OCH3 and Cp) to ethenone

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