The reversible addition-fragmentation chain transfer (RAFT) copolymerizations of 2-((8-hydroxyquinolin-5-yl)methoxy)ethyl methacrylate (HQHEMA) with styrene (St) or methyl methacrylate (MMA) were successfully carried out in the presence of 2-cyanoprop-2-yl dithionaphthalenoate (CPDN). The polymerization behaviors showed the typical living natures by the first-order polymerization kinetics, the linear dependence of molecular weights of the polymers on the monomer conversions with the relatively narrow molecular weight distributions , and the successful chain extension experiments. The soluble polymers having tris(8-hydroxyquinoline)aluminum ( ) and bis(8-hydroxyquinoline) znic(II) ( ) side chains were obtained via complexation of the polymers with aluminium isopropoxide or zinc acetate in the presence of monomeric 8-hydroxyquinoline, which had strong fluorescent emission at 520？nm. The obtained polymers were characterized by GPC, NMR, UV-vis, and fluorescent spectra. 1. Introduction In recent years, organic electroluminescence (EL) display devices have attracted more intensive attention as a promising technology for flat panel display [1]. Many emitting materials, including low-weight molecules and polymers, have been designed and utilized in fabricating organic light emitting diodes (OLEDs) [2–5]. Among them, metal 8-hydroxyquinoline (Mqn) chelates, especially for tris(8-hydroxyquinoline)aluminum (Alq3), and bis(8-hydroxyquinoline) znic(II) (Znq2) have been extensively investigated for their high stabilities, good emissions, and electron-transporting properties [6–8]. Compared with low-weight 8-hydroxyquinoline (Mqn) chelate, the polymers containing Mqn pendant groups combine the fluorescent property of Mqn and the processability of the polymer [6, 7, 9]. Up to now, two types of Mqn-containing polymers (main-chain type and side-chain type) have been reported. Yamamoto and Yamaquchi reported the synthesis of poly(quinolinol) [10] and poly(aryleneethynylene) [11] containing 8-quinolinol moieties. On the other hand, various side-chain type polymers including poly(arylene ether) [12], copolymers of 7-allyl-, or 7-(2-methylvinyl)-functionalized derivatives of 8-hydroquinoline with styrene [13], functionalized polystyrene [14], and copolymers of methacrylates having 8-hydroxyquinoline moieties were also successfully prepared [15]. Furthermore, Mqn-containing polymers were obtained by the reaction of the above polymers with metal compounds in the presence of monomeric 8-hydroxyquinoline. Meyers and Weck, reported the synthesis of an Alq3-functionalized polymer
References
[1]
C. W. Tang and S. A. Vanslyke, “Organic electroluminescent diodes,” Applied Physics Letters, vol. 51, no. 12, pp. 913–915, 1987.
[2]
C. H. Chen, J. Shi, and C. W. Tang, “Recent developments in molecular organic electroluminescent materials,” Macromolecular Symposia, vol. 125, pp. 1–48, 1997.
[3]
Y. Hamada, T. Sano, H. Fujii, Y. Nishio, H. Takahashi, and K. Shibata, “White-light-emitting material for organic electroluminescent devices,” Japanese Journal of Applied Physics, vol. 35, no. 10, pp. L1339–L1341, 1996.
[4]
H. Tanaka, S. Tokito, Y. Taga, and A. Okada, “Novel metal-chelate emitting materials based on polycyclic aromatic ligands for electroluminescent devices,” Journal of Materials Chemistry, vol. 8, no. 9, pp. 1999–2003, 1998.
[5]
Y. Qiu, Y. Shao, D. Zhang, and X. Hong, “Preparation and characterization of high efficient blue-light emitting materials with a secondary ligand for organic electroluminescence,” Japanese Journal of Applied Physics, vol. 39, no. 3, pp. 1151–1153, 2000.
[6]
A. Meyers and M. Weck, “Design and synthesis of -functionalized polymers,” Macromolecules, vol. 36, no. 6, pp. 1766–1768, 2003.
[7]
A. Meyers, C. South, and M. Weck, “Design, synthesis, characterization, and fluorescent studies of the first zinc-quinolate polymer,” Chemical Communications, vol. 10, no. 10, pp. 1176–1177, 2004.
[8]
B. J. Chen, W. Y. Lai, Z. Q. Gao, C. S. Lee, S. T. Lee, and W. A. Gambling, “Electron drift mobility and electroluminescent efficiency of tris(8-hydroxyquinolinolato) aluminum,” Applied Physics Letters, vol. 75, no. 25, pp. 4010–4012, 1999.
[9]
T. Takayama, M. Kitamura, Y. Kobayashi, Y. Arakawa, and K. Kudo, “Soluble polymer complexes having -type pendent groups,” Macromolecular Rapid Communications, vol. 25, no. 12, pp. 1171–1174, 2004.
[10]
T. Yamamoto and I. Yamaguchi, “Enzymatic synthesis of poly(quinolinol) and its fluorescent aluminum complex,” Polymer Bulletin, vol. 50, no. 1-2, pp. 55–60, 2003.
[11]
T. Iijima, S.-I. Kuroda, and T. Yamamoto, “Main-chain-type 8-quinolinol polymers: synthesis, optical properties, and complex formation with metals,” Macromolecules, vol. 41, no. 5, pp. 1654–1662, 2008.
[12]
J. Lu, A. R. Hlil, Y. Meng, et al., “Synthesis and characterization of a novel -containing polymer,” Journal of Polymer Science A, vol. 38, no. 16, pp. 2887–2892, 2000.
[13]
Y.-F. Duann, Y.-J. Liao, W. Guo, and S.-M. Chang, “The characteristic of photoluminescence of tris-(7-substituted-8-hydroxyquinoline) aluminum complexes and polymeric complexes,” Applied Organometallic Chemistry, vol. 17, no. 12, pp. 952–957, 2003.
[14]
X.-Y. Wang and M. Weck, “Poly(styrene)-supported and ,” Macromolecules, vol. 38, no. 17, pp. 7219–7224, 2005.
[15]
Q. Mei, N. Du, and M. Lu, “Synthesis, characterization and thermal properties of metaloquinolate-containing polymers,” European Polymer Journal, vol. 43, no. 6, pp. 2380–2386, 2007.
[16]
S. Li, M. Lin, J. Lu, and H. Liang, “Synthesis, self-assembly, and formation of complex micelles for diblock copolymer of 2-((8-hydroxyquinolin-5-yl)methoxy)ethyl methacrylate and styrene,” Macromolecules, vol. 42, no. 4, pp. 1258–1263, 2009.
[17]
M. Kamigaito, T. Ando, and M. Sawamoto, “Metal-catalyzed living radical polymerization,” Chemical Reviews, vol. 101, no. 12, pp. 3689–3745, 2001.
[18]
M. Kamigaito, T. Ando, and M. Sawamoto, “Metal-catalyzed living radical polymerization: discovery and developments,” Chemical Record, vol. 4, no. 3, pp. 159–175, 2004.
[19]
K. Matyjaszewski and J. Xia, “Atom transfer radical polymerization,” Chemical Reviews, vol. 101, no. 9, pp. 2921–2990, 2001.
[20]
C. J. Hawker, “Molecular weight control by a “living” free-radical polymerization process,” Journal of the American Chemical Society, vol. 116, no. 24, pp. 11185–11186, 1994.
[21]
J. Chiefari, Y. K. Chong, F. Ercole, et al., “Living free-radical polymerization by reversible addition—fragmentation chain transfer: the RAFT process,” Macromolecules, vol. 31, no. 16, pp. 5559–5562, 1998.
[22]
V. Percec, T. Guliashvili, J. S. Ladislaw, et al., “Ultrafast synthesis of ultrahigh molar mass polymers by metal-catalyzed living radical polymerization of acrylates, methacrylates, and vinyl chloride mediated by SET at ,” Journal of the American Chemical Society, vol. 128, no. 43, pp. 14156–14165, 2006.
[23]
G. Moad, E. Rizzardo, and S. H. Thang, “Living radical polymerization by the RAFT process,” Australian Journal of Chemistry, vol. 58, no. 6, pp. 379–410, 2005.
[24]
J. Zhu, X. Zhu, Z. Cheng, F. Liu, and J. Lu, “Study on controlled free-radical polymerization in the presence of 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN),” Polymer, vol. 43, no. 25, pp. 7037–7042, 2002.
[25]
Q. Mei, N. Du, and M. Lu, “Synthesis and characterization of high molecular weight metaloquinolate-containing polymers,” Journal of Applied Polymer Science, vol. 99, no. 4, pp. 1945–1952, 2006.
[26]
W. Zhang, X. Zhu, D. Zhou, X. Wang, and J. Zhu, “Reversible addition-fragmentation chain transfer polymerization of 2-naphthyl acrylate with 2-cyanoprop-2-yl 1-dithionaphthalate as a chain-transfer agent,” Journal of Polymer Science A, vol. 43, no. 12, pp. 2632–2642, 2005.
