Phosphorus-nitrogen compounds. Part 52. The reactions of octachlorocyclotetraphosphazene with sodium 3-(N-ferrocenylmethylamino)-1-propanoxide: Investigations of spectroscopic, crystallographic and stereogenic properties

Abstract

The reaction of octachlorocyclotetraphosphazene (tetramer, N4P4Cl8, 1) with two mole equivalents of sodium 3-(N-ferrocenylmethylamino)-1-propanoxide (2) gave the novel ansa-spiro (3), 2-trans-6-dispiro (4), 2-cis-6-dispiro (5), 2-trans-4-dispiro (6) and 2-cis-4-dispiro (7) cyclotetraphosphazenes. However, when the reaction was carried out with 1 and three mole equivalents of 2, seven products observed with respect to the 31P NMR spectrum of the reaction mixture. Five of these products were identified as 3, 4, 5, 6 and 7, and the other two products are expected to be 2-trans-4-trans-6-trispiro (8) derived from 4 and/or 6, and 2-trans-4-cis-6-trispiro (9) derived from 5 and/or 7. Both of the trispiro products (8 and 9) were not isolated using column chromatography. Besides, when the reaction was made with 1 and excess amount of 2, the tetraspiro products were not observed by TLC and 31P NMR spectrum of the reaction mixture. The structures of cyclotetraphosphazene derivatives were verified by ESI-MS, FTIR, 1H, 13C and 31P NMR spectral data. The molecular and solid state structures of 3, 5 and 6 were established by X-ray diffraction method. The X-Ray crystallographic data indicate that compounds 3 and 6 have three-different and two equivalent chiral P centers, respectively. The absolute configurations of 3 and 6 were also found to be as SS'S'' and RR.