A series of linear aromatic polyethers containing triazole units were synthesized via the direct click reaction of dibromide and bisethynyl compounds in the presence of sodium azide as one pot reaction. The structures of polymers were approved by using IR and 1H NMR techniques. The solubility experiments showed that polymers have good solubility in polar aprotic solvents such as DMSO, DMF, and NMP at higher temperatures. Thermal stability of the polymers was measured using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) which indicated that they possessed good thermal stability ( up to 558°C) and high (191.7–260°C) under N2 atmosphere. All the polymers were amorphous according to the DSC and X-ray diffraction. These polymers exhibited strong UV-vis absorption maxima near to 400？nm and up to 500？nm in DMSO solution. 1. Introduction Poly(arylene ether)s (PAEs) are known as an important class of the high-performance polymeric materials which consist of aromatic rings and ether linkages [1]. So far, one of the most common and effective methods for the formation of aromatic ether linkages in polyether synthesis was nucleophilic aromatic substitution (SNAr) reaction. Different poly(aryl ether)s including poly(ether sulfone)s, poly(ether ketone)s, and poly(ether imide)s have been prepared using the SNAr reaction and commercialized [2]. However, this method suffers from some serious limitations such as high temperature and harsh conditions. In addition, only appropriate monomers having electron-withdrawing groups at the ortho position to the leaving group could be polymerized. Recent innovations in synthetic methodology have improved polymer synthesis, enabling the custom design of a large variety of macromolecular architectures under incorporation of desired functional units [3, 4]. To find an outstanding polymerization reaction, polymer chemists and biotechnologists have increasingly turned towards advanced synthetic organic concepts. In this respect, the most interesting one is click chemistry well documented in the past decade. The applications of click reactions are wide in scope. The click reactions give excellent yields and generate inoffensive by-products that can be removed by convenient methods. The required process characteristics include simple reaction conditions, readily available reactants, solvent free reactions or using a solvent that is benign or easily removed, and simple product isolation [5]. To date, the most popular reaction that satisfied these features is the 1,3-dipolar cycloaddition, also known as Huisgen
References
[1]
R. J. Cotter, Engineering Plastics: A Handbook of Polyaryl Ethers, Gordon and Breach, Amsterdam, The Netherlands, 1995.
[2]
I. S. Chung and S. Y. Kim, “Poly(arylene ether)s via nitro displacement reaction: synthesis of poly(biphenylene oxide)s containing trifluoromethyl groups from AB type monomers,” Macromolecules, vol. 33, no. 26, pp. 9474–9476, 2000.
[3]
C. J. Hawker and K. L. Wooley, “The convergence of synthetic organic and polymer chemistries,” Science, vol. 309, no. 5738, pp. 1200–1205, 2005.
[4]
S. Hecht, “Construction with macromolecules,” Materials Today, vol. 8, no. 3, pp. 48–55, 2005.
[5]
H. C. Kolb, M. G. Finn, and K. B. Sharpless, “Click chemistry: diverse chemical function from a few good reactions,” Angewandte—Chemie International Edition, vol. 40, no. 11, pp. 2004–2021, 2001.
[6]
R. Huisgen, S. Guenter, and M. Leander, “1.3-Dipolare cycloadditionen, XXXII. Kinetik der additionen organischer azide an CC-mehrfachbindungen,” Chemische Berichte, vol. 100, no. 8, pp. 2494–2507, 1967.
[7]
R. Huisgen, 1, 3-Dipolar Cycloaddition Chemistry, John Wiley & Sons, New York, NY, USA, 1984.
[8]
V. V. Rostovtsev, L. G. Green, V. V. Fokin, and K. B. Sharpless, “A stepwise huisgen cycloaddition process: copper(I)-catalyzed regioselective “ligation” of azides and terminal alkynes,” Angewandte—Chemie International Edition, vol. 41, no. 14, pp. 2596–2599, 2002.
[9]
C. W. Torn？e, C. Christensen, and M. Meldal, “Peptidotriazoles on solid phase:？ [1,2,3]-triazoles by regiospecific copper(I)-catalyzed 1,3-dipolar cycloadditions of terminal alkynes to azides,” The Journal of Organic Chemistry, vol. 67, no. 9, pp. 3057–3064, 2002.
[10]
A. J. Scheel, H. Komber, and B. I. Viot, “Novel hyperbranched poly([1,2,3]-triazole)s derived from AB2 monomers by a 1,3-dipolar cycloaddition,” Macromolecular Rapid Communications, vol. 25, no. 12, pp. 1175–1180, 2004.
[11]
P. Wu, A. K. Feldman, A. K. Nugent et al., “Efficiency and fidelity in a click-chemistry route to triazole dendrimers by the copper(I)-catalyzed ligation of azides and alkynes,” Angewandte—Chemie International Edition, vol. 43, no. 30, pp. 3928–3932, 2004.
[12]
D. J. V. C. van Steenis, O. R. P. David, G. P. F. van Strijdonck, J. H. Van Maarseveen, and J. N. H. Reek, “Click-chemistry as an efficient synthetic tool for the preparation of novel conjugated polymers,” Chemical Communications, no. 34, pp. 4333–4335, 2005.
[13]
B. Helms, J. L. Mynar, C. J. Hawker, and J. M. J. Fréchet, “Dendronized linear polymers via “click chemistry”,” Journal of the American Chemical Society, vol. 126, no. 46, pp. 15020–15021, 2004.
[14]
B. Parrish, R. B. Breitenkamp, and T. Emrick, “PEG- and peptide-grafted aliphatic polyesters by click chemistry,” Journal of the American Chemical Society, vol. 127, no. 20, pp. 7404–7410, 2005.
[15]
J. B. Carroll, B. J. Jordan, H. Xu, et al., “Model systems for flavoenzyme activity: site-isolated redox behavior in flavin-functionalized random polystyrene copolymers,” Organic Letters, vol. 7, no. 13, pp. 2551–2554, 2005.
[16]
J. A. Opsteen and J. C. M. van Hest, “Modular synthesis of block copolymers via cycloaddition of terminal azide and alkyne functionalized polymers,” Chemical Communications, no. 1, pp. 57–59, 2005.
[17]
D. D. Díaz, S. Punna, P. Holzer, et al., “Click chemistry in materials synthesis. 1. Adhesive polymers from copper-catalyzed azide-alkyne cycloaddition,” Journal of Polymer Science A, vol. 42, no. 17, pp. 4392–4403, 2004.
[18]
D. A. Ossipov and J. Hilborn, “Poly(vinyl alcohol)-based hydrogels formed by “click chemistry”,” Macromolecules, vol. 39, no. 5, pp. 1709–1718, 2006.
[19]
Y. Nagao and A. Takasu, “Click polyester: synthesis of polyesters containing triazole units in the main chain by click chemistry and improved thermal property,” Macromolecular Rapid Communications, vol. 30, no. 3, pp. 199–203, 2009.
[20]
R. X. Yao, L. Kong, Z. S. Yin, and F. L. Qing, “Synthesis of novel aromatic ether polymers containing perfluorocyclobutyl and triazole units via click chemistry,” Journal of Fluorine Chemistry, vol. 129, no. 10, pp. 1003–1010, 2008.
[21]
P. Wu and V. V. Fokin, “Catalytic dipolar cycloaddition of azides and alkynes: reactivity and applications,” Aldrichimica Acta, vol. 40, no. 1, pp. 7–17, 2007.
[22]
M. Meldal and C. W. Torn？e, “Cu-catalyzed azide-alkyne cycloaddition,” Chemical Reviews, vol. 108, no. 8, pp. 2952–3015, 2008.
[23]
G. C. Tron, T. Pirali, R. A. Billington, P. L. Canonico, G. Sorba, and A. A. Genazzani, “Click chemistry reactions in medicinal chemistry: applications of the 1,3-dipolar cycloaddition between azides and alkynes,” Medicinal Research Reviews, vol. 28, no. 2, pp. 278–308, 2008.
[24]
V. D. Bock, H. Hiemstra, and J. V. Maarseveen, “CuI-catalyzed alkyne–azide “click” cycloadditions from a mechanistic and synthetic perspective,” European Journal of Organic Chemistry, vol. 2006, no. 1, pp. 51–68, 2006.
[25]
L. Wang, J. Li, and L. Wang, “Study on synthesis of paeks containing triazole units through click reaction and their properties,” Bulletin of the Korean Chemical Society, vol. 32, no. 9, pp. 3306–3310, 2011.
[26]
I. B. Mansour, K. Alouani, E. Chauveau, V. Martin, F. Schiets, and R. Mercier, “Synthesis and characterisation of poly(ester-amide)s from aromatic bisoxazoline precursors,” European Polymer Journal, vol. 46, no. 4, pp. 814–820, 2010.
[27]
C. Saravanan, S. Senthil, and P. Kannan, “Click chemistry-assisted triazole-substituted azobenzene and fulgimide units in the pendant-based copoly(decyloxymethacrylate)s for dual-mode optical switches,” Journal of Polymer Science A, vol. 46, no. 23, pp. 7843–7860, 2008.
[28]
B. Happ, C. Friebe, A. Winter, M. D. Hager, and U. S. Schubert, “Click chemistry meets polymerization: controlled incorporation of an easily accessible ruthenium(II) complex into a PMMA backbone via RAFT copolymerization,” European Polymer Journal, vol. 45, no. 12, pp. 3433–3441, 2009.
