1,1,3,3-Tetrakis(dimethylamino)-1 lambda(5),3 lambda(5)-diphosphete, (1), r
eacts with 2-cyano-pyridine to yield 6-pyridyl-1-aza-2 lambda(5),4 lambda(5
)-diphosphinine (3). 3 is characterized by its H-1, P-31, and C-13 NMR, mas
s, and IR spectra as well as the results of the X-rap structure analysis.