Synthesis and Characterization of New Azo-Based Cyclotriphosphazene Derivatives with Decyl and Chloro Terminal Groups

New cyclotriphosphazene derivatives bearing azo linkages and decyl and chloro terminal groups were successfully synthesized and characterized. Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, and CHN elemental analysis were employed to characterize the synthesized compounds. The presence of the azo linkage was confirmed by the characteristic N=N stretching band at ~1500 cm−1, while the terminal groups were identified by the C–Cl stretching band at ~735 cm−1 for the chloro-substituted derivative and Csp3–H stretching bands at ~2900 cm−1 for the decyl-substituted derivative. The 1H and 13C NMR spectra further supported the proposed molecular structures through characteristic chemical shifts associated with the different proton and carbon environments. The 31P NMR spectra displayed a singlet, supporting the complete substitution of phosphorus atoms with identical side chains and the formation of an equivalent phosphorus environment. Furthermore, CHN elemental analysis provided additional evidence for the successful synthesis and high purity of the compounds, with a maximum deviation of approximately 1% from the calculated elemental compositions. Overall, the incorporation of the azo linkage and different terminal groups demonstrates the structural versatility of cyclotriphosphazene derivatives and provides a basis for further investigation of their properties and potential applications, particularly their fire-retardant performance.