CYANOPHOSPHAZENE SMALL MOLECULES AND HIGH POLYMERS - SYNTHESIS AND STRUCTURE

The synthesis and properties of cyclic and high-polymeric cyanophospha zenes were investigated. The interaction of N3P3(OR)5Cl (OR = OC6H5, O CH2CF3, OCH2CH2OCH2CH2OCH3) with potassium cyanide in the presence of 18-crown-6 ether in acetonitrile yielded small-molecule cyclic cyanoph osphazenes, N3P3(OR)5(CN). Reaction of trans-nongeminal-[NP(NMe2)Cl] 3 with potassium cyanide in the presence of tetra-n-butylammonium bromi de in acetonitrile resulted in the formation of trans-nongeminal-[NP(N Me2)(CN)]3. X-ray crystallographic analyses of N3P3(OC6H5)5(CN) and no ngeminal-[NP(NMe2)(CN)]3 were carried out. N3P3(OC6H5)5(CN) crystalliz ed in the monoclinic space group P2(1)/n. Unit cell parameters were a = 10.759(4) angstrom, b = 9.662(3) angstrom, c = 29.466(4) angstrom, a nd beta = 96.92(3)degrees. The structure refined with final R = 0.045 and R(w) = 0.047. nongeminal-[NP(NMe2)(CN)]3 crystallized in the tricl inic space group P1BAR. Unit cell parameters were a = 6.715(3) angstro m, b = 8.538(5) angstrom, c = 14.910(6) angstrom, alpha = 92.10(4)degr ees, beta = 105.41(4)degrees, and gamma = 95.75(4)degrees. The structu re refined to a final R = 0.044 and R(w) = 0.061. The syntheses of hig h-polymeric cyanophosphazenes were carried out by the reaction of [NPR 1.5Cl0.5]n (R = OC6H5 or NMe2) with potassium cyanide in the presence of 18-crown-6 ether in THF to yield [NP(OC6H5)1.53(CN)0.33-Cl0.14]n an d [NP(NMe2)1.5(CN)0.3Cl0.2]n. Attempts to replace there remaining chlo rine atoms in [NP(OC6H5)1.5(CN)0.33-Cl0.17]n by reaction with NaOC6H5 resulted in the displacement of both chloro and cyano units to give [N P(OC6H5)2]n. Treatment of [NP(NMe2)1.5(CN)0.3Cl0.2]n with excess HNMe2 gave [NP(NMe2)1.7(CN)0.3]n. The polymers were studied by a combinatio n of NMR, IR, DSC, GPC, TGA, and elemental analysis.