An answer to the spiro versus ansa dilemma in cyclophosphazenes

The reactions of cyclotriphosphazene with 2-(2-hydroxyethylamino)ethanol. Spectroscopic studies of the derived products

“…The new synthesized cyclophosphazene derivatives (3-10) contain ≡PCl 2, ≡P(OR) 2 and ≡P(OR)Cl groups and the 31 P NMR spectra are observed as A 2 X (or A 2 B) and AMX spin types [2a, 3, 11, 12, 56], which can be readily assigned by consideration of signal intensities, chemical shifts and coupling patterns. Selected 31 P NMR chemicals shifts and coupling constants of compounds (3)(4)(5)(6)(7)(8)(9)(10) are summarized in Table 1. Within the A 2 X (or AB 2 ) spin systems, the proton-coupled 31 P NMR spectra suggest that the A 2 parts of the spectra arise from ≡PCl 2 (in compounds 3, 8); ≡P(OR)Cl (in compounds 5, 6 and 9) and ≡P(OR)OR (in compound 4) groups, giving rise to doublet structures and the X parts of the spectra arise from ≡P(OR) 2 (in compounds 3 and 6), ≡PCl 2 (in compounds 4, 5 and 9) and the ≡P(OR)Cl (in compound 8) groups, giving rise to triplet structures.…”

“…The reactions of cyclotriphosphazene (1) with tri-functional nucleophilic reagents have been previously studied [49][50][51][52][53]. The reactions with spermidine (as a triamine) gave only one product, N 3 P 3 Cl 4 NH[(CH 2 ) 3 NH(CH 2 ) 4 NH] 2 N 3 P 3 Cl 5 . This was confirmed by single crystal Xray diffraction to have a 6-membered spiro ring, involving one N 3 P 3 moiety and a bridge to a second such unit [49,50].…”