ChemCatSusDe addresses some of the industrial and economical issues of our society: fossil fuel depletion, use of renewable resources derived from the biomass, environmentally friendly chemistry for a sustainable future. At its core lies the versatility of complexes of zinc, magnesium, calcium, strontium and barium (the so-called bio-metals): green catalysts able to perform both the polymerisation of cyclic esters and highly atom-efficient hydroelementation reactions will be designed.The objectives defined by the researcher and the host institution in Rennes are:- Synthesis of well-defined complexes of the large alkaline-earth (Ca, Sr, Ba). The coordination chemistry of these metals in the presence of chelating, mono-anionic ligands will be studied. Owing to the extreme oxophilic nature of these elements, these catalytic precursors are expected to display excellent activities. The same synthetic strategies will also be extended to the preparation of complexes of the smaller zinc and magnesium, which display an excellent compromise between stability and catalytic activity- Use of these complexes for the catalytic immortal ring-opening polymerisation of cyclic monomers derived from renewable bioresources for the production of biocompatible and/or biodegradable polymers. All catalysts will be used for the polymerisation of lactide and monomers such as morpholinediones and b- or g-valerolactones- Hydroelementation of terminal alkenes catalyzed by heteroleptic amido-alkaline-earth complexes. Catalysts for the 100% atom-efficient hydrosilylation, -phophination and -amination of unsaturated substrates will be prepared- Study of the stability and reactivity of the targeted heteroleptic complexes by theoretical calculations: the design of catalytic systems will be elaborated and/or optimized according to preliminary calculations or those based on experimental structural data.- Development of long-term collaborations between the host and return institutions