Phosphole tetramer, reaction with

The reaction of the phosphole tetramer (PC4-2-Ph-3,4-Me2)4 (71) with either sodium or potassium yields the complexes 72 and 73, respectively (Scheme 6) (26). 

A similar strategy was employed to assemble the tetramer 32 which features four central phosphole units and four peripheral phosphinine rings. Importantly, reduction of this oligomer with 4 equiv. of sodium naphthalenide sodium resulted in the cleavage of the two P-P bonds and formation of the phospholide anions. This dianionic species was found to be sufficiently stable to be characterized. Trapping reaction of dianion 33 with methyl iodide afforded the tetradentate ligand 34 (Scheme 9). 

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