Di‐tert‐butyldiphosphatetrahedrane: Catalytic Synthesis of the Elusive Phosphaalkyne Dimer

Abstract

While tetrahedranes as a family are scarce, neutral heteroatomic species are all but unknown, with the only reported example being AsP 3 . Herein, we report the first isolation of a neutral heteroatomic X 2 Y 2 molecular tetrahedron (X, Y = p‐block elements), which is also the first example of the long‐sought‐after free phosphaalkyne dimer. Di‐ tert ‐butyldiphosphatetrahedrane, ( t BuCP) 2 , is formed from the monomer t BuCP in a nickel‐catalyzed dimerization reaction using [(NHC)Ni(CO) 3 ] (NHC = 1,3‑bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene (IMes) and 1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene (IPr)). Single‑crystal X‐ray structure determination of a silver(I) complex confirms the structure of ( t BuCP) 2 . The influence of the N‑heterocyclic carbene ligand on the catalytic reaction was investigated, and a mechanism was elucidated using a combination of synthetic and kinetic studies and quantum chemical calculations.