REACTION OF 1,1,3,3-TETRAKIS(DIMETHYLAMINO)-1λ5,3λ5-DIPHOSPHETE, 1, WITH CARBONDISULFIDE II. DIHYDRO-λ5-PHOSPHETES; NMR ISOTOPE EFFECTS

1,1,3,3-Tetrakis(dimethylamino)-1-phospha-3-phosphonium-2-dithio-carboxylato-cyclobutene-1, 2,(1) is thermally unstable. By heating it is converted quantitatively into [1,1-bis(dimethylamino)-3-thioxo-3,4-dihydro-1 lambda(5)-phosphete-2-yl]-phosphonothioic bis(dimethylamide), 3. Reaction of the 2,4-dimethylderivative of the title compound 1, i.e. 4. with CS2 yields [1,1-bis(dimethylamino)-2,4-dimethyl-3-thioxo-2,3-dihydro-1 lambda(5)-phosphete-2-yl]-phosphonothioic bis(dimethylamide) 7. The new compounds are characterized by their properties and their nmr, ir and mass spectra. Isotope effects on delta(31)P of are described. The results of the X-ray structural analyses of 3 and 7 are reported and discussed.