1,3,2-Diheterophospholane complexes: access to new tuneable precursors of phosphanoxyl complexes and P-functional polymers.

Synthesis of a testbed of P-H functional diheterophospholane complexes (3 and 6a,b) with no or little steric bulk at the α-position was achieved using [NEt 4 ][WH(CO) 5 ] as a combined reductant and complexation reagent. Reaction with TEMPO leads to P-OTEMP substituted tungsten complexes (4 and 7a,b) possessing different thermostabilities towards N-O bond cleavage. The transient phosphanoxyl complexes obtained were used for the polymerisation of styrene and acrylonitrile. DFT calculations were performed on the formation of various open-shell complexes and Loewdin spin density distributions.