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In this study, a series of cyclotriphosphazene derivatives containing a Schiff base (3a-3d) were synthesized by the reactions of hexachlorocyclotriphosphazene (1) with bis-aryl Schiff bases (2a-2d) having different terminal groups (H, F, Cl, and Br). The products (3a-3d) were characterized by elemental and mass analyses, FT-IR, and 1 H, 13 C, and 31 P NMR spectroscopies. Furthermore, the structure of compound 3a was also determined by X-ray crystallography. The thermal behaviors and the spectral properties of the new cyclotriphosphazene compounds (3a-3d) were investigated and the results were compared in the series.

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The substitution reactions of the monospiro and geminally disubstituted cyclotriphosphazene derivatives NPClR (R = OCH(CF)CHO (1a), SPh (1b), OCHCHCHO (1c), NHPh (1d), OCHCHCHNH (1e), NHBu (1f)) with two secondary amines (pyrrolidine and dimethylamine) were carried out to investigate geminal or non-geminal directing effects in mixed substituent cyclophosphazenes. The relative amounts of isomeric products, geminal and non-geminal trans or cis, was established quantitatively from the P NMR spectra of the reaction mixtures. Although secondary amines generally follow a non-geminal pathway in the reactions with hexachlorocyclotriphosphazene, in this work, the reactions of two different secondary amines with some NPClR (R = OCHCHCHNH, NHPh, NHBu) derivatives lead to the formation of geminal products. We have shown that this observation depends on the electron-donating properties of the PR groups. Isolated compounds were analyzed by standard techniques such as elemental analysis, mass spectrometry, and H andP NMR spectroscopy. The structures of compounds for which suitable crystals could be obtained were characterized by X-ray crystallography.