Steric control in the oligomerisation of phosphazane dimers; towards new phosphorus–nitrogenmacrocycles

Abstract

The reaction of [ClP(μ-N^tBu)]₂ (1) with H₂O (1 : 2 equivalents) in the presence of excess Et₃N gives the new chain compound [(μ-O){P(μ-N^tBu)₂P(H)O}₂] (3), consisting of two P₂N₂ rings linked by a μ-O atom and terminating in P^V(H)O groups. A similar chain species is obtained from the reaction of the lithiate of [(^tBuNH)P(μ-N^tBu)₂P(H)O] (5) with [ClP(μ-N^tBu)₂P(NH^tBu)] (2), the product being [(μ-O){P(μ-N^tBu)₂P(NH^tBu)}₂] (6). Compounds 3 and 6 are the first examples of O-bridged chain phosphazanes and potential precursors to new phosphorus-nitrogen macrocycles. The syntheses and X-ray structures of 3, 5 and 6 are reported.