Phosphinidenes: Fundamental Properties and Reactivity.

Phosphinidenes are heavy congeners of nitrenes that have been broadly used as in situ reagents in synthetic phosphorus chemistry and also serve as versatile ligands in coordination with transition metals. However, the detection of free phosphinidenes is largely challenged by their high reactivity and also the lack of suitable synthetic methods, rendering the knowledge about the fundamental properties of this class of low-valent phosphorus compounds limited. Recently, an increasing number of free phosphinidenes bearing prototype structural and bonding properties have been prepared for the first time, thus enabling the exploration of their distinct reactivity from the nitrene analogues. This Concept article will discuss the experimental approaches for the generation of the highly unstable phosphinidenes and highlight their distinct reactivity from the nitrogen analogues so as to stimuate future studies about their potential applications in phosphorus chemistry.