Catalytic Access to Polyazanes – Polyazanes
Catalytic linking of nitrogen atoms
The synthesis of N-N single bonds is underdeveloped, partly because of the repulsion between the non-bonding doublets of nitrogen, and partly because nitrogen prefers to form triple bonds. The aim of the project is to identify new routes to these structures from ureas, using nickel catalysis and/or light.
New ways of building N-N bonds using metals
The toolkit to build N–N bonds, let alone in a repeated way, remains very limited. Synthetic approaches to functionalized hydrazines are most often based on already established N–N bonds, or on ageless ionic approaches, and therefore C–(NN) bond disconnections are almost always favored. Nonetheless, there are signs that the neglect period for N–N bond construction is ending, especially with regard to organometallic catalysis. In the present proposal we will endeavor to develop a novel approach to N–N bond formation, i.e a nickel-catalyzed decarbonylative coupling process from ureas and related molecules– releasing only CO as byproduct – and apply it to the synthesis of linear as well as branched polyazanes.
By combining the skills of LHCEP (in the chemistry of polyazo derivatives and radicals) and the SCORE@ICBMS team (organometallic catalysis and radicals), we are seeking to form hydrazines first (by the N+N route) before generalizing the approach to linear or branched polyazanes (nN + pN) by controlling the regioselectivity of the coupling
All substrates have been prepared by various routes, including novel approaches (Task 1). We are currently working on the oxidative addition step in the C-N or C-F bond. Simple insertions into amides or acylfluorides work except when the required nitrogen is also present on the substrate (urea, carbamoyl fluoride). We are currently modeling this step to understand the origin of the reactivity loss
Thanks to modelling, we can hope to identify the blockage and adapt the metal's coordination sphere and we will also consider light to get additional activation
We propose to build N–N single bonds using transition metal catalysis, therefore adding a novel tool to install a bond present in many natural and pharmaceutical compounds. Beyond, it will open access to poly-nitrogenated frameworks via the construction of various all poly-N chains to be used as precursors and/or building blocks for the preparation of heterocycles, energetic materials, helical templates and/or ligands of transition metals.
Project coordination
Emmanuel LACOTE (Institut de Recherche de Chimie Paris)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Partnership
ICBMS Université Claude Bernard Lyon 1
LHCEP Université Claude Bernard Lyon 1
IRCP Institut de Recherche de Chimie Paris
Help of the ANR 372,900 euros
Beginning and duration of the scientific project:
January 2023
- 48 Months
