NHCs as Neutral Donors towards Polyphosphorus Complexes
Felix Riedlberger, Stefano Todisco, Piero Mastrorilli, Alexey Y. Timoshkin, Michael Seidl, Manfred Scheer
Abstract
Abstract The first adducts of NHCs (=N‐heterocyclic carbenes) with aromatic polyphosphorus complexes are reported. The reactions of [Cp*Fe(η 5 ‐P 5 )] ( 1 ) (Cp*=pentamethyl‐cyclopentadienyl) with IMe (=1,3,4,5‐tetramethylimidazolin‐2‐ylidene), IMes (=1,3‐bis(2,4,6‐trimethylphenyl)‐imidazolin‐2‐ylidene) and IDipp (=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene) led to the corresponding neutral adducts which can be isolated in the solid state. However, in solution, they quickly undergo a dissociative equilibrium between the adduct and 1 including the corresponding NHC. The equilibrium is influenced by the bulkiness of the NHC. [Cp′′Ta(CO) 2 (η 4 ‐P 4 )] (Cp′′=1,3‐di‐ tert ‐butylcyclopentadienyl) reacts with IMe under P atom abstraction to give an unprecedented cyclo‐P 3 ‐containing anionic tantalum complex. DFT calculations shed light onto the energetics of the reaction pathways.