One of the most recent fascinating discoveries in main group element chemistry is that certain non-metallic reactive species behave quite similarly to transition metals (TMs) and are able to activate small molecules (with strong bonds) such as H-H, previously believed to be only possible using TMs. This discovery, providing interesting perspectives such as the use of such non-metallic species as an alternative to TMs with original properties to exploit new chemistry, is particularly important. However, our current knowledge to master the parameters controlling such properties is still far from satisfactory. In this project, we propose a fundamental and exploring research to establish a new methodology to induce the TM-like behavior of Si(II) [and Al(I)] species (silylenes and alumylenes) taking advantage of electronic and steric effects of TM-substituents. We expect to use such TM-substituted silylenes as unprecedented hybrid (non-metal and metal) binuclear complexes.

Initially considered as an inert metal, gold is now recognized as very powerful catalyst in organic synthesis. One very important area in homogenous catalysis for which gold complexes have not been considered yet, is the field of polymerization catalysis, particularly for the coordination-insertion polymerization of olefins. In contrast, late transition metal complexes such as Pd(II) and Ni(II) have been shown to be very good catalyst for the polymerization of olefins and the incorporation of polar monomers. However several limitations are still observed with these complexes, in particular for the copolymerization of olefins and polar monomers. Stimulated by the isolobal analogy between Au(III) and Pd(II) complexes, we propose in this project to prepare original bidentate Au(III)-alkyl complexes and investigate their behaviour in coordination-insertion polymerization of olefins. The main objective of this project is to shed light on a new facet of gold chemistry, we aim to thoroughly investigate the reactivity of gold towards olefins and to highlight that gold(III) complexes should be seriously considered for coordination-insertion polymerization catalysis. For that purpose, a set of gold(III)-alkyl complexes will be prepared using two main synthetic strategies. The reaction of selected complexes with model monomers such as ethylene and acrylonitrile will be explored by combining a set of experimental and theoretical techniques. In depth mechanistic studies of the coordination-insertion reaction will be carried out to gain fundamental knowledge on the key parameters governing the reactivity and selectivity of these gold complexes. Best representatives will be evaluated for ethylene and propylene polymerization and for copolymerization of ethylene with polar vinyl monomers.

ENigM proposes a family of evolutionary mimics of nitrogenase cofactor FeMo-co, for the understanding of the structure/properties relationship accounting for the exceptional reducing power of this complex structure. As a benchmark reaction, we choose the reduction of CO2, as it will enlarge and complete the information provided in the frame of N2 reduction usually considered in the field of nitrogenase mimics. This work will allow for the identification of systems able to perform the multi-electron reduction of small molecules, as the conversion of CO2 to formate, methanol or methane. The initial platform shows several structural analogies with FeMo-co: coordination sphere made of carbon and sulfur only, strongly charged carbon bridging between two iron centers. The easy modification of the ligand brings a strong modularity to our system, without the risk of denaturing the central metal-carbon interaction. A methodological ground will be established : redox and acido-basic properties of the initial platform, reactivity in the presence of CO2. This family of FeMo-co mimics will then be extended by stepwise increase of the number of metallic centers, while studying the properties of the obtained clusters.

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.