論文の公開元へSynthesis of New Polymers Possessing Dense Triazole Backbone by Copper(I)-Catalyzed Azide–Alkyne Cycloaddition
概要
In this study, new polymers possessing dense triazole backbone have been successfully synthesized by CuAAC polymerization. The structure and properties of new dense triazole polymers were systematically investigated.
In Chapter 2, a new polyanion with a dense 1,2,3-triazole backbone, poly(AH), was synthesized by CuAAC polymerization of tBuAH followed by hydrolysis of the t-Bu ester groups. The metal ion adsorption tests of poly(AH)Na indicated that poly(AH)Na was applicable to an adsorbent for metal ions, especially Fe3+ ion (98.57 ± 0.03 mg g–1). The ratio of T1 values for the 1H NMR signals in the presence and absence of 0.6 mM Fe3+ indicated that Fe3+ ions were adsorbed more preferably onto the 1,2,3-triazole residues.
In Chapter 3, a procedure for constructing of 12-membered cyclic structure 13 has been developed by accidently. Cyclic dimer 15 was synthesized and a new polycyclic polymer (Mw = 2.0 × 104) possessing dense 1,2,3-triazole backbone was successfully synthesized by CuAAC polymerization of 15. The DFT calculation indicated that the polycyclic octamer took a helical conformation presumably because of the bulky 12-membered macrocycle units. An alternating copolymer of t-Bu ester and t-Bu amide side chains was also successfully synthesized.
In Chapter 4, the interaction of polycyclic polymers with PdCl2 was investigated by 1H NMR. In the presence of PdCl2, 1H NMR spectra showed broader signals as well as new signals assignable to the complexed 1,2,3-triazole and methine protons at lower magnetic fields. When excess PPh3 was added to the mixture of polycyclic polymer and PdCl2, the signals due to complexed species disappeared, indicating that the coordination of PPh3 to PdCl2 caused dissociation of the polymer complex. On the basis of the 2D DOSY data, the coordination of polycyclic polymer to PdCl2 made the polymer take a more compact conformation. As the temperature was increased, the 1H NMR signals due to the complexed state became less significant. Assuming that the 1,2,3-triazole moiety in macrocycle and PdCl2 form a two-to-one complex for simplicity, the Kapp values were roughly estimated. Based on the van’t Hoff plot, the difference in Gibbs energy between the free and complexed states was estimated to be ca. 12 kJ mol–1.
In conclusion, a new polyanion and a new polycyclic polymer possessing dense 1,2,3-triazole backbone were successfully prepared by CuAAC polymerization, and the interaction of the polyanion with metal ions and of polycyclic polymers with PdCl2 were investigated. Taking advantage of unique property of 1,2,3-triazole, these polymers exhibit interesting properties. Hence, this work should provide access to new triazole-based functional materials.
