In the current societal context facing high energy prices and resource shortages together with high pollution, catalysis using sunlight as energy source is a promising way to develop innovative sustainable processes for industrial implementations as proven by different approaches described in the literature. PLASMOCAT focuses on visible-light mediated dehydrogenation processes under oxidant-free conditions, from low to high challenging substrates (alcohols – amines – alkanes), obtaining both feedstock (carbonyl derivatives, imines, nitriles, alkenes) and molecular hydrogen, a carbon-neutral fuel. Also, PLASMOCAT foresees to couple the dehydrogenation of alcohols to the decarbonylation of aldehydes as a tandem process, with the aim of obtaining alkanes, including long carbon chain hydrocarbons. Therefore, composite materials combining photo-activation sites and catalytically active sites are considered. Although photocatalytic dehydrogenation of alcohols has been achieved with nanoparticles (NPs) of Pt, Au or Ag on TiO2, the employment of zero-valent NPs of 3d transition metals is almost unexplored. Thus, the synthesis of original plasmonic NPs of Cu and Co immobilized on different semiconductors, metallic and non-metallic ones, will be developed. Understanding the mechanisms of photocatalyzed dehydrogenation will be crucial for the design of catalytic systems with improved activity and selectivity. Accordingly, operando techniques (React-IR, UV-Vis, advanced X-ray techniques) will be applied to determine the kinetic reaction profiles and elucidate the interactions between the metallic NPs and the support. Moreover, a theoretical approach to understand the plasmonic behavior of metallic NPs and electronic transfer phenomena will be addressed. PLASMOCAT provides an excellent frame to train young researchers in innovative and sustainable nanocatalytic processes, leading to the synthesis of added value products, including the production of hydrogen.

The activation of heteroatom–hydrogen (X–H) bonds has traditionally been preserved for transition metals. Recently, it has been shown that oxidative addition of X–H bonds (amines, alcohols,…) can be achieved with geometrically constrained s3 phosphorus compounds. However, the reductive elimination step from the resulting hydrophosphiranes (P(V)) is not possible in many cases. The present project proposes a dual catalysis approach, combining phosphorus P(III) organocatalysis with photoredox catalysis to solve this issue. A highly original approach for the formation of oxygen and nitrogen centered radicals will be provided with a high potential of valorization. The generated radicals will be employed in organic synthesis and mechanistic aspects of this chemistry will be thoroughly investigated. This conceptually new approach will open a new avenue for the generation of synthetically useful radicals that are derived from X–H derivatives possessing high dissociation energies. The most efficient systems identified in this work will be evaluated as high-performance photoinitiating systems of polymerization, showing their high potential applications. From the high reactivity of the generated initiating radicals, polymerization under mild conditions (longer wavelengths) will be carried out; this would constitute a significant breakthrough compared to the current systems.

The overarching objective of this proposal is the development of innovative catalytic methodologies for P-C bond formation, and in particular for the challenging preparation of P-heterocycles, compounds in demand by the scientific community for optoelectronic, catalysis or pharmaceutical applications. Yet, methodologies for their preparation lack of generality. Here, we propose to take profit the considerable reactivity boost provided by MLC catalysis for the preparation of P-heterocycles, and more precisely for the creation of C-P bonds via the addition of P(O)-H bonds across CC triple bonds. The properties of the targeted MLC catalyst, such as the Brönsted basicity of the pincer backbone, as well as, the Lewis acidity of the metal centre, will be tuned by varying the structure of the ligand precursors (substituents, scaffold, donor groups) and the metal (Ni, Pd, Pt). This work will in addition lead to the expansion the scope of MLC catalysis with G10 metals, much less developed than with TM from G7-9. Moreover, the development of new strategies for the synthesis of P-heterocycles is an ideal case study to investigate a new dual catalytic approach associating MLC with Photoredox catalysis. This multicatalytic approach combines p-activation of CC triple bond by an electrophilic metal with the activation of the P(O)-H bond by the PC* in association with the basic ligand backbone. Feasibility of the Dual PC-MLC Catalysis will be explored from a mechanistic point of view thanks to thorough physical organic studies of the substrates and the pincer complexes. This will include characterisation of the ground and excited states, and investigation of possible interactions between excited state of the photocatalyst and substrates as well as pincer complexes. Demonstration of the proof of concept of this unprecedented strategy will open an avenue to the activation of other protic functions whose pKa make activation solely by the MLC catalyst unlikely. An additional target of the project is the development of sustainable synthetic methodologies towards P-containing substrates. They start from hypophosphorous acid (HPA) and thus bypass the generally used PCl3, an energy demanding and waste producing starting material

Carbenes are highly reactive species that find many applications in organic chemistry and beyond. Diazirines are carbene precursors that are more stable, less dangerous and tolerate a much broader substitution pattern than the traditional diazoalkanes. Those have been extensively studied but their large-scale application is limited by their poor stability and structural requirements. In sharp contrast, the carbene-related reactivity of diazirines remains mostly untapped toward applications in organic synthesis. This project thus aims at harnessing the potential of diazirine-born carbenes by overcoming the decoupling between their generation and their control. To achieve this, DIAZICOOL proposes to take advantage of modern synthetic techniques, recently uncovered activation conditions and various catalysts to generate, trap and use these reactive carbene species in relevant reactions.

In this project, we will use a combined experimental and theoretical approach in order to address three ambitious research topics. The common ground for these three sub-projects is the use of the highly reactive “Ni(diphosphine)” Ni(0) 14 electron fragment. The first sub-chapter addresses the current challenge of developing cross-coupling processes between C-sp3 (alkyl-halides) and organometallic compounds with first row transition metals. Preliminary results prove the Ni(diphosphine) fragment to be competent in such catalytic process, being the first example of its kind. The second project deals with the dehydrogenation of alkanes into alkenes using homogeneous catalysts. This very challenging task has never been reported with first row transition metal systems. Preliminary results indicate a stoichiometric transformation of the alkane by the above mentioned Ni fragment, opening the way for further improvements, and catalytic extension using different strategies (use of sacrificial alkene, use of tandem catalysis…). The third experimental project deals with CO2 functionalization. One of the originalities of our proposal is the design of the optimal Ni fragment for each process by theoretical calculations. This optimization step will only be possible after a comparison between experiments and theory for the known Ni(diphosphine) fragment.