Cooperative Iron-Aluminium Reactivity for Dinitrogen Activation

Abstract

We report a novel bimetallic approach utilizing cooperative Fe─Al reactivity for N₂ activation on the Cp*Fe(1,2-Cy₂PC₆H₄AlEt) platform, effectively capturing two N₂ molecules through intermolecular Fe─N≡N─Al coordination. Characterizations of the N₂-bridged Fe─Al dimer (2) using Mössbauer spectroscopy coupled to density functional theory (DFT) calculations reveals its electronic structure as a resonance hybrid between Fe(II)-Al(I) and Fe(0)-Al(III). The flexible, covalent Fe─Al bonding facilitates the subsequent alkylation of the Al site with ⁿBuLi, leading to the formation of a dinitrogen-lithiated complex (3) that enables the silylation of the terminal N atom. Our findings highlight the significance of leveraging Fe─Al effects as an electron buffer to achieve facile N₂ activation.

Keywords: Aluminum; Iron complex; Metal–metal bonding; Metal–metal cooperation; N2 activation.