Room Temperature Ring-Opening Polymerization of cyclo-Phosphazenes Christopher A. Reed, Center for S and P Block Chemistry, University of California, Riverside, CA 92521 Using 31P NMR, end groups and intermediates in the ring-opening polymerization of cyclo-N3P3Cl6 have been observed for the first time. See color coding in Figure. This was made possible by the discovery of trialkylsilyl carboranes as a room temperature catalysts for a reaction normally carried out at 200 ºC. “monomer” polymer catalyst 5 min 30 min 60 min 90 min 120 min cyclo-pentamer cyclo-hexamer 150 min cyclo-tetramer 180 min