Studies of phosphazenes. Part 25. Synthesis, nuclear magnetic resonance spectroscopy, and mode of formation of (aziridino)(triphenylphosphazenyl)cyclotriphosphazenes. X-Ray crystal structure and enzyme-inhibiting activity of N3P3(NPPh3)(NC2H4)5
Aziridino (HNC2H4) reacts with the triphenylphosphazenyl derivative N3P3(NPPh3)Cl5(1) to yield the compounds N3P3(NPPh3)(NC2H4)nCl5 –n[n= 1–5; (3)–(9)], the structures of which are elucidated by 1H and 31P n.m.r. spectroscopy. The fluoro-analogue, N3P3(NPPh3)F5(2), is unreactive even under drastic conditions. The chlorine replacement pattern and the associated mechanistic aspects are discussed. The X-ray crystal structure analysis of N3P3(NPPh3)(NC2H4)5(9) shows a novel conformation of the –NPPh3 substituent in which one of the phenyl groups lies in a plane nearly perpendicular and in close proximity to the –NC2H4 group at the P(NPPh3)(NC2H4) site. The n.m.r. [1H, 13C, and 31P] parameters of (9) are discussed in relation to its structure. The enzyme-inhibiting activity of (9) is compared with that of N3P3(NC2H4)6.