An Intramolecular Bis(Amino)Phosphine‐Stabilised Phosphinidene: Synthesis and CuCl Coordination

Abstract Extending the available intramolecularly‐stabilised phosphinidene ligands, we report a novel naphthalene supported system derived from readily available starting materials. Specifically, 1,8‐bis(diaminophosphino)naphthalene, naphth‐1,8‐{P(NEt 2 ) 2 } 2 ( 1 ), reacts with ethereal HCl to form the mixed diphosphine naphth‐1‐(PCl 2 )‐8‐{P(NEt 2 ) 2 } 2 as a phosphoranide Zwitterion, which is readily reduced with elemental Mg in forming the target intramolecularly‐stabilised phosphinidene 3 . The electronic nature of this species is explored through computational DFT, NBO, and TD‐DFT analyses, indicating a high electron density at the P I centre, which delocalizes across the naphthalene ring lending this deep red‐purple compound its colour. The coordination capacity of 3 is demonstrated through its reaction with excess CuCl, which surprisingly leads to exclusive formation of the 2 : 1 complex of 3 to Cu, giving initial insights into the coordination chemistry of this novel ligand.