Metal‐Free Scission of the NO ⁺ Triple Bond

Abstract

ABSTRACT We report the facile and direct room temperature unimolecular scission of the N≡O + triple bond, one of the strongest known chemical bonds with a bond dissociation energy of 1049 kJ mol −1 . The reaction of NO[Al(OR F ) 4 ] (R F  = C(CF 3 ) 3 ) and PNP t Bu (2,6‐bis(di‐ tert ‐butylphosphinomethyl)pyridine) in CH 2 Cl 2 yields the 1,2,3‐diazaphospholo[1,5‐ a ]pyridinium derivative [DAPP t Bu ] + [Al(OR F ) 4 ] – ( 1 ), featuring the complete cleavage of the N≡O + bond. At −30°C, the reaction intermediate [PNOP t Bu ] + [Al(OR F ) 4 ] – ( 2 ), which contains the novel bridging P═N−O−P + motif, can be isolated. Mechanistic insights were gained through quantum chemical calculations, which elucidated the formation pathways of 1 and 2 , while NMR spectroscopic kinetic studies quantified the conversion rate from 2 to 1 .