A novel cyclotriphosphazene-based low-molecular weight organogelator was prepared by immobilization of six dialkylated L-glutamide derivatives on a cyclotriphosphazene core, and its ability as a self-assembling organogelator was investigated. The organogelator exhibited enhanced gelation ability and chirality, and thixotropic property for self-restoring to a gel state; this was compared to the corresponding L-glutamide-derived organogelator without the core. The gelation test, transmission electron microscopy observation, and circular dichroism (CD) spectral study showed that the gelation and aggregation ability were enhanced by immobilization onto the cyclotriphosphazene core. Gels in chloroform and cyclohexane-ethanol (95:5) mixture showed an unusual thixotropic property.

Well-ordered and highly-oriented structures were constructed on a cyclotriphosphazene core by the ring-opening polymerization of N-carboxyanhydride of γ-methyl and γ-benzyl L-glutamates with hexakis(4aminophenoxy)cyclotriphosphazene as an initiator. The polymers were found to form α-helix conformation from the positions of amide I and amide II in fourier transform infrared spectroscopy (FT-IR) spectra and negative Cotton effects in circular dichroizm (CD) spectra. Both the γ-methyl and γ-benzyl L-glutamate hybrids displayed conformational stability in their hexafluoro-2-propanol (HFIP) solutions under temperature changes between 5 and 60 • C. The oligo(γbenzyl L-glutamate) with short chain length (average 8 residue per each chain) showed extremely high α-helical content, which was determined to be almost 100%. These results demonstrate that the cyclotriphosphazene core exerts a strong secondary structure stabilizing effect.

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