Abstract: | Gasphase Reactions. 92 Thermal Elimination of HCl from Alkyldichlorophosphanes (H3C/H)3C? PCl2 to Phosphaalkenes (H3C/H)2C?PCl and Phosphaalkines (H3C/H)C≡P The alkyldichlorophosphanes H3C? PCl2, ClH2? PCl2, (H3C)H2C? PCl2 and (H3C)2HC? PCl2 split off HCl on heating in a gasflow under reduced pressure. PE spectroscopic gas analysis proves that under these conditions the short-lived phosphaalkenes H2C?PCl, (H3C)H2C?PCl and – catalyzed by MgCl2? MgO/SiO2]∞ – (H3C)2C?PCl as well as the phosphaalkines HC≡P and (H3C)C≡P are formed, all of which can be isolated by low temperature condensation. Based on the PES ionization patterns recorded and on the MNDO calculations for their assignment, the πCP multiple bonds are discussed. The presumable pathway of the HCl elimination is rationalized for (H3C)H2C? PCl2 by an approximate MNDO energy hypersurface. |