Periodic Reporting for period 3 - BECAME (Bimetallic Catalysis for Diverse Methane Functionalization)
Okres sprawozdawczy: 2023-09-01 do 2025-02-28
Methane is the main component of natural gas, thus representing one of the most abundantly carbon-based chemical feedstocks. Moreover, it could be considered as a possible renewable resource as it is present in biogas, produced by methanogens in animals and decaying matter. Nowadays, methane is mostly burned for energy production; however, its high volatility and flammability complicate its use as fuel due to storage and transport problems. More importantly, the combustion of hydrocarbons releases carbon dioxide that contribute to atmospheric pollution and climate change. As a result, the combustion of methane should be seen only as a provisional resource rather than an alternative fuel to oil or coal. Another current use of methane is the production of syngas, which can be further transformed into methanol or higher hydrocarbons in a separate step. However, the methods used for this purpose are based on high-energy demanding and cost-intensive processes. Given the increasing abundance of methane (according to several studies the reserves of natural gas are expected to grow significantly worldwide in the coming decades), methane may soon become the main raw material. For this reason, and the problematic associated to its greenhouse gas nature, the development of new technologies that allow methane to be directly and efficiently converted into high value-added products, such as commodity and fine chemicals, is of utmost importance for our society.
The low reactivity and intrinsic inertness of methane C-H bonds bring extreme challenges for catalytic systems, not only in the activation of this alkane, but also in controlling the selectivity of its functionalization. Therefore, novel synthetic methodologies that facilitate methane conversion into a wide range of useful products under mild conditions are needed but, at the same time, represent a huge challenge for the chemical science.
The overall aim of BECAME is the development of new synergistic catalytic processes that allow methane (and additionally other light alkanes) to be directly converted into highly valuable products through dual metal catalyzed C-C bond forming reactions under mild conditions. The use of C-C bond formation, which is the basis for the synthesis of essential molecules, as a general platform for direct methane functionalization will facilitate its conversion into higher hydrocarbons without the need to generate syngas or intermediates such as halogenated hydrocarbons. Moreover, the direct use of methane as methylating agent in organic transformations will lead to clean and highly atom-efficient processes.
The low reactivity and intrinsic inertness of methane C-H bonds bring extreme challenges for catalytic systems, not only in the activation of this alkane, but also in controlling the selectivity of its functionalization. Therefore, novel synthetic methodologies that facilitate methane conversion into a wide range of useful products under mild conditions are needed but, at the same time, represent a huge challenge for the chemical science.
The overall aim of BECAME is the development of new synergistic catalytic processes that allow methane (and additionally other light alkanes) to be directly converted into highly valuable products through dual metal catalyzed C-C bond forming reactions under mild conditions. The use of C-C bond formation, which is the basis for the synthesis of essential molecules, as a general platform for direct methane functionalization will facilitate its conversion into higher hydrocarbons without the need to generate syngas or intermediates such as halogenated hydrocarbons. Moreover, the direct use of methane as methylating agent in organic transformations will lead to clean and highly atom-efficient processes.
In the BECAME project, we are trying to develop novel synthetic methodologies based on the concept of dual metal catalysis that allow simple unactivated alkanes to be directly used in cross-coupling reactions, with the special aim to apply these new methods to the functionalization of methane and other gaseous alkanes. The project lies on our combined experience in organometallic chemistry, catalysis and organic synthesis.
We have developed a dual catalytic system comprising tungsten and copper complexes that facilitates the direct C-H allylation of a range of simple liquid alkanes, including hydrocarbon based natural products. This discovery set the basis for the development of a novel C-H allylation methodology that can now be applied to gaseous alkanes. We are currently exploring this new methodology, which has already rendered very promising results. Efforts has also been directed to the development of enantioselective transformations of alkanes. Preliminary results have demonstrated the feasibility to apply our strategy to liquid alkanes. We are now trying to expand this methodology to gaseous alkanes.
During this period, the use of new bimetallic MOFs (based on Pd and Fe) as heterogeneous bimetallic catalysts has appeared as an attractive alternative to achieve C-C bond forming reactions with hydrocarbon-derived compounds. We have already proven the ability of these new materials as efficient catalyst, and we are trying to expand their catalytic portfolio towards new hydrocarbon functionalization reactions.
We have developed a dual catalytic system comprising tungsten and copper complexes that facilitates the direct C-H allylation of a range of simple liquid alkanes, including hydrocarbon based natural products. This discovery set the basis for the development of a novel C-H allylation methodology that can now be applied to gaseous alkanes. We are currently exploring this new methodology, which has already rendered very promising results. Efforts has also been directed to the development of enantioselective transformations of alkanes. Preliminary results have demonstrated the feasibility to apply our strategy to liquid alkanes. We are now trying to expand this methodology to gaseous alkanes.
During this period, the use of new bimetallic MOFs (based on Pd and Fe) as heterogeneous bimetallic catalysts has appeared as an attractive alternative to achieve C-C bond forming reactions with hydrocarbon-derived compounds. We have already proven the ability of these new materials as efficient catalyst, and we are trying to expand their catalytic portfolio towards new hydrocarbon functionalization reactions.
As a result of this first research period, we have been able to establish a reliable and efficient strategy for the activation of light alkanes. The combination of this activation step with different transition metal mediated functionalization reactions have already allowed to develop novel transformations that bring new opportunities for light alkane modification through C-C bond formation. So far, we have achieved the C-H allylation of this type of alkanes and preliminary results point towards a very promising scenario for developing enantioselective transformations such as asymmetric conjugate additions that are completely unprecedented for these hydrocarbons. During the next research period, our newly developed dual metal catalysis strategy will be expanded to other transformations that will provide new tools for C-X and C-H alkylations and olefin hydroalylations.