Parameters Governing Ruthenium Sawhorse-Based Decarboxylation of Oleic Acid

Ruthenium-catalyzed decarboxylation of 9-cis-octadecenoic is a path to produce biobased olefins. Here, a mechanistic study of this reaction was undertaken utilizing a closed reaction system and a pressure reactor. The proposed mechanism of an isomerization followed by a decarboxylation reaction was consistent with a mathematical kinetic model. That same model was able to accurately predict CO₂ evolution. Additionally, computational chemistry was used to determine that the barrier of the oleic acid decarboxylation reaction is 249 kJ mol^–1. Using the new information, the efficacy of the decarboxylation reaction was improved to an overall catalytic efficiency of 850 total turnovers

Parameters Governing Ruthenium Sawhorse-Based Decarboxylation of Oleic Acid

Ruthenium-catalyzed decarboxylation of 9-cis-octadecenoic is a path to produce biobased olefins. Here, a mechanistic study of this reaction was undertaken utilizing a closed reaction system and a pressure reactor. The proposed mechanism of an isomerization followed by a decarboxylation reaction was consistent with a mathematical kinetic model. That same model was able to accurately predict CO₂ evolution. Additionally, computational chemistry was used to determine that the barrier of the oleic acid decarboxylation reaction is 249 kJ mol^–1. Using the new information, the efficacy of the decarboxylation reaction was improved to an overall catalytic efficiency of 850 total turnovers

Ferrous Carbonyl Dithiolates as Precursors to FeFe, FeCo, and FeMn Carbonyl Dithiolates

Reported are complexes of the formula Fe­(dithiolate)­(CO)₂(diphos) and their use to prepare homo- and heterobimetallic dithiolato derivatives. The starting iron dithiolates were prepared by a one-pot reaction of FeCl₂ and CO with chelating diphosphines and dithiolates, where dithiolate = S₂(CH₂)₂^2– (edt^2–), S₂(CH₂)₃^2– (pdt^2–), S₂(CH₂)₂(C­(CH₃)₂)^2– (Me₂pdt^2–) and diphos = <i>cis</i>-C₂H₂(PPh₂)₂ (dppv), C₂H₄(PPh₂)₂ (dppe), C₆H₄(PPh₂)₂ (dppbz), C₂H₄[P­(C₆H₁₁)₂]₂ (dcpe). The incorporation of ⁵⁷Fe into such building block complexes commenced with the conversion of ⁵⁷Fe into ⁵⁷Fe₂I₄(^<i>i</i>PrOH)₄, which then was treated with K₂pdt, CO, and dppe to give ⁵⁷Fe­(pdt)­(CO)₂(dppe). NMR and IR analyses show that these complexes exist as mixtures of all-cis and trans-CO isomers, edt^2– favoring the former and pdt^2– the latter. Treatment of Fe­(dithiolate)­(CO)₂(diphos) with the Fe(0) reagent (benzylideneacetone)­Fe­(CO)₃ gave Fe₂(dithiolate)­(CO)₄(diphos), thereby defining a route from simple ferrous salts to models for hydrogenase active sites. Extending the building block route to heterobimetallic complexes, treatment of Fe­(pdt)­(CO)₂(dppe) with [(acenaphthene)­Mn­(CO)₃]⁺ gave [(CO)₃Mn­(pdt)­Fe­(CO)₂(dppe)]⁺ ([<b>3d</b>(CO)]⁺). Reduction of [<b>3d</b>(CO)]⁺ with BH₄^– gave the <i>C</i>_<i>s</i>-symmetric μ-hydride (CO)₃Mn­(pdt)­(H)­Fe­(CO)­(dppe) (H<b>3d</b>). Complex H<b>3d</b> is reversibly protonated by strong acids, the proposed site of protonation being sulfur. Treatment of Fe­(dithiolate)­(CO)₂(diphos) with CpCoI₂(CO) followed by reduction by Cp₂Co affords CpCo­(dithiolate)­Fe­(CO)­(diphos) (<b>4</b>), which can also be prepared from Fe­(dithiolate)­(CO)₂(diphos) and CpCo­(CO)₂. Like the electronically related (CO)₃Fe­(pdt)­Fe­(CO)­(diphos), these complexes undergo protonation to afford the μ-hydrido complexes [CpCo­(dithiolate)­HFe­(CO)­(diphos)]⁺. Low-temperature NMR studies indicate that Co is the kinetic site of protonation

Ferrous Carbonyl Dithiolates as Precursors to FeFe, FeCo, and FeMn Carbonyl Dithiolates

Reported are complexes of the formula Fe­(dithiolate)­(CO)₂(diphos) and their use to prepare homo- and heterobimetallic dithiolato derivatives. The starting iron dithiolates were prepared by a one-pot reaction of FeCl₂ and CO with chelating diphosphines and dithiolates, where dithiolate = S₂(CH₂)₂^2– (edt^2–), S₂(CH₂)₃^2– (pdt^2–), S₂(CH₂)₂(C­(CH₃)₂)^2– (Me₂pdt^2–) and diphos = <i>cis</i>-C₂H₂(PPh₂)₂ (dppv), C₂H₄(PPh₂)₂ (dppe), C₆H₄(PPh₂)₂ (dppbz), C₂H₄[P­(C₆H₁₁)₂]₂ (dcpe). The incorporation of ⁵⁷Fe into such building block complexes commenced with the conversion of ⁵⁷Fe into ⁵⁷Fe₂I₄(^<i>i</i>PrOH)₄, which then was treated with K₂pdt, CO, and dppe to give ⁵⁷Fe­(pdt)­(CO)₂(dppe). NMR and IR analyses show that these complexes exist as mixtures of all-cis and trans-CO isomers, edt^2– favoring the former and pdt^2– the latter. Treatment of Fe­(dithiolate)­(CO)₂(diphos) with the Fe(0) reagent (benzylideneacetone)­Fe­(CO)₃ gave Fe₂(dithiolate)­(CO)₄(diphos), thereby defining a route from simple ferrous salts to models for hydrogenase active sites. Extending the building block route to heterobimetallic complexes, treatment of Fe­(pdt)­(CO)₂(dppe) with [(acenaphthene)­Mn­(CO)₃]⁺ gave [(CO)₃Mn­(pdt)­Fe­(CO)₂(dppe)]⁺ ([<b>3d</b>(CO)]⁺). Reduction of [<b>3d</b>(CO)]⁺ with BH₄^– gave the <i>C</i>_<i>s</i>-symmetric μ-hydride (CO)₃Mn­(pdt)­(H)­Fe­(CO)­(dppe) (H<b>3d</b>). Complex H<b>3d</b> is reversibly protonated by strong acids, the proposed site of protonation being sulfur. Treatment of Fe­(dithiolate)­(CO)₂(diphos) with CpCoI₂(CO) followed by reduction by Cp₂Co affords CpCo­(dithiolate)­Fe­(CO)­(diphos) (<b>4</b>), which can also be prepared from Fe­(dithiolate)­(CO)₂(diphos) and CpCo­(CO)₂. Like the electronically related (CO)₃Fe­(pdt)­Fe­(CO)­(diphos), these complexes undergo protonation to afford the μ-hydrido complexes [CpCo­(dithiolate)­HFe­(CO)­(diphos)]⁺. Low-temperature NMR studies indicate that Co is the kinetic site of protonation