| dc.description.abstract | The thermal condensation of alkyl/aryl trifluoroethoxy-(silylimino)phosphoranes, Me(,3)SiN = PRR'(OCH(,2)CF(,3)), provides an efficient method for the synthesis of fully P-C bonded polyphosphazenes. Oxidation of (disilylamino)phosphines, (Me(,3)Si)(,2)NPRR', with Br(,2) affords the bromo(imino)phosphoranes, Me(,3)SiN = PRR' (Br), in high yields. The displacement of Br in these compounds by -OCH(,2)CF(,3) yields the polymer precursor trifluoroethoxyphosphoranes. When R is Ph and R' is CH(,2)Ph, a powdery, soluble polymer is obtained. The incorporation of one (or two) allyl substituent into the precursor provides tough, flexible, highly crosslinked homopolymers, and swellable (or soluble), lightly crosslinked, fibrous copolymers. These polymers are of considerable interest as fabrication materials. Alkyl and alkaryl substituted trifluoroethoxyphosphoranes of the type Me(,3)SiN = PR(OCH(,2)CF(,3)) (CH(,2)R') {R' = H, Ph, CH=CH(,2)} undergo a facile deprotonation reaction with n-BuLi. The carbanionic intermediates react smoothly with Ph(,2)PCl to yield polymer precursors bearing the phosphine ligand. The synthesis of Fe(CO)(,4) complexes, and in one case a Cr(CO)(,5) complex, of the ligands is reported. The trifluoroethoxyphosphorane Me(,3)SiN=PMe(CH(,2)PPh(,2)) (OCH(,2)CF(,3)) condenses to the homo- and copolymer, { N = PMe(CH(,2)PPh(,2)) }(,n) and { { N = PMe(,2)}(,x){N = PMe(CH(,2)PPh(,2))}(,y)}(,n), respectively. The Fe(CO)(,4) and Mo(CO)(,5) complexes of the copolymer represent the first examples of fully P-C bonded polyphosphazenes bearing metalcarbonyl moieties. Reactions of the carbanion from Me(,3)SiN = PMe(,2)(OCH(,2)CF(,3)) with Br(,2) and EtOC(O)Cl are also discussed. | |
