The oxidative addition of Cl2 (using SO2Cl2) to the six-membered ring (R2PN)(SN)2 (R = Me, Ph) produces the mixed phosphazene–thiazyl heterocycles, (R2PN)(NSCl)2, which react with Me3SiNSNSiMe3 to give the bicyclic compounds R2PS3N5. The latter undergo thermal decomposition, at ca. 100 °C in toluene, via reductive elimination of an NSN unit to regenerate (R2PN)(SN)2 in high yield. Kinetic measurements of this process, using 31P nmr spectroscopy, yield an activation energy of 102.4 ± 6.0 kJ mol−1 for the release of the NSN fragment from Me2PS3N5. The thermolysis route has been used to prepare the thermally unstable (F2PN)(SN)2, characterized as a 1:1 adduct with norbornadiene.
Analytical Currents: Counting rare tumor cells in vivo | Nano-optode sensors are brighter than QDs and biocompatible | Optical microcavities for detecting single molecules | Protein folding by fast 2D NMR spectroscopy | Separation by solid-supported bilayer electrophoresis | Raman microspectroscopy of mitochondria