Aj. Elias et al., Syntheses and experimental studies on the relative stabilities of spiro, ansa, and bridged derivatives of cyclic tetrameric fluorophosphazene, INORG CHEM, 40(9), 2001, pp. 2120-2126
Reactions of (CF2CH2OSiMe3)(2) and CF2(CF2CH2OSiMe3)(2) with N4P4Fdelta (1)
in a 1:2.5 molar ratio resulted in the formation of monospiro compounds [(
CF2CH2O)(2)PN] (F2PN)(3) (2) and [CF2(CF2CH2O)(2)PN](F2PN)(3) (4) as well a
s the intermolecular bridged compounds F7N4P4OCH2CF2CF2CH2OP4N4F7 (3) and F
7N4P4OCH2CF2CF2CF2CH2-OP4N4F7 (5). An equimolar reaction of dilithiated 1,3
-propanediol with 1 resulted in the 1,3-ansa-substituted compound CH2(CH2O)
(2)[P(F)N](2)(F2PN)(2) (6) as the major product in good yield. However, an
analogous reaction of the dilithiated 1,3-propanedithiol with 1 gave only t
he spirocyclic compound CH2(CH2S)(2)(PN)(F2PN)(3) (8). The molecular struct
ures of 2 and 6 were determined by single-crystal X-ray diffraction. In the
presence of catalytic amounts of CsF in THF, the bridged compound 3 was co
nverted to the spirocyclic compound 2 while the 1,3-ansa compound 6 under s
imilar conditions transformed into the monospiro-substituted compound CH2(C
H2O)(2)(PN)(F2PN)(3) (7). These transformations were monitored by time-depe
ndent F-19 and P-31 NMR studies.