New Cyclic Phosphazenes with (Trimethylsilyl)methyl Side Groups: X-ray Crystal Structure of [NP(CH2SiMe3)2]3 and Its Conversion to (NPMe2)3

Harry R. Allcock, William D. Coggio, Masood Parvez, Michael L. Turner

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15 Scopus citations


The synthesis of [NP(CH2SiMe3)2]3 has been achieved in almost quantitative yield via the reaction of Me3SiCH2Li with (NPF2)3 in tetrahydrofuran at 40 °C, followed by addition of a proton source. Treatment of [NP(CH2SiMe3)2]3 with nBu4N+F gave (NPMe2)3 in 60% yield. Partially substituted trimers of the formula N3P3Fx(CH2SiMe3)6-x, where x = 2 and 4, were also prepared. The interaction of (NPF2)3 with Me3SiCH2Li involves a metal-hydrogen exchange side reaction to generate species such as N3P3-(CH2SiMe3)5(CHSiMe3)Li+, hence the need for subsequent protonation. Attempts to replace the fluorine atoms in gem-N3P3F4(CH2SiMe3)2 by treatment with NaOCH2CF3 led also to C-Si bond cleavage to generate gem-N3P3(OCH2CF3)4Me2. No C-Si bond cleavage occurred during the attempted preparation of gem-N3P3(OCH2CF3)2(CH2SiMe3)4, and none was detected when [NP(CH2SiMe3)2]3 was treated with NaOCH2CF3. The structure of [NP(CH2SiMe3)2]3 has been determined by single-crystal X-ray diffraction methods. Crystals were monoclinic with a P21/n space group, with a = 11.012 (2) A, b = 19.851 (5) Å, c = 19.554 (8) Å, β = 90.51 (2)°, V = 4309.3 Å3, and Z = 4. A comparison is made with other alkyl- and (alkylsilyl)cyclo-triphosphazenes.

Original languageEnglish (US)
Pages (from-to)677-683
Number of pages7
Issue number3
StatePublished - Mar 27 1991

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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