Spiro,ansa-derivatives of cyclotetraphosphazenes with a tetrafluorobutane-1,4-diol

The reaction of the octachlorocyclotetraphosphazene, N₄P₄Cl₈ (1), in three stoichiometries (1:1, 1:2 and 1:3) with the sodium derivative of the fluorinated diol, 2,2,3,3-tetrafluorobutane-1,4-diol (2), in THF solution at room temperature produced seven products, whose structures have been characterized by elemental analysis, mass spectrometry, ¹H, ¹⁹F, ³¹P NMR spectroscopy and by X-ray crystallography, where suitable single crystals were obtained: the mono-spiro compound, N₄P₄Cl₆(OCH₂CF₂CF₂CH₂O) (3), its ansa isomer (4), cis- and trans-bis-spiro derivatives N₄P₄Cl₄(OCH₂CF₂CF₂CH₂O)₂ (5 and 6), tris-spiro compound N₄P₄Cl₂(OCH₂CF₂CF₂CH₂O)₃ (7), its mono-spiro-bis-ansa isomer (8) and tetrakis-spiro compound N₄P₄(OCH₂CF₂CF₂CH₂O)₄, (9). X-ray crystallographic studies confirmed that the structure of the mono-spiro-bis-ansa isomer (8) has been reported as a first example in the literature. The results of all reactions were compared with previous work on the reaction of hexachlorocyclotriphosphazene, N₃P₃Cl₆ with the sodium derivative of the diol (2), in a 1:1.2 mole ratio in the in the same solvent, THF, and with the reaction of octafluorocyclotetraphosphazene, N₄P₄F₈, with the silyl derivative of the diol (2), (Me₃SiOCH₂CF₂)₂, in a 1:0.4 mole ratio in THF.