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A series of carbosilane dendrimers with acetyl end-group: From synthesis to their unique optical characteristics
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Chinese Chemical Letters 20 (2009) 1085–1087 www.elsevier.com/locate/cclet
Short communication
A series of carbosilane dendrimers with acetyl end-group: From synthesis to their unique optical characteristics Wen Yan Sun, Hai Feng Lu, Deng Xu Wang, Sheng Yu Feng * School of Chemistry and Chemical Engineering Shandong University, Ji’nan 250100, China Received 11 February 2009
Abstract A series of carbosilane dendrimers with acetyl end-group were synthesized. Their structures were characterized by 1H NMR, IR, and MS, respectively. Then dendrimers were coordinated with lanthanide ions (Eu3+ and Tb3+, respectively). The luminescence spectra of the complexes show narrow-width emissions in visible light region. # 2009 Sheng Yu Feng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Synthesis; Carbosilane dendrimer; Luminescence; Lanthanide ions
Carbosilane dendrimer is a novel class of macromolecules and could be widely used in the fields of medicinal chemistry, hostguest chemistry, and catalysis [1–4]. They are particularly suitable for preparing metal nanoparticles because of their monodispersity, regular and highly branched architecture, multiple surface functionality, and cavities in the structure. Some lanthanide ions, for example Eu3+ and Tb3+, possess good luminescence characteristics (visible light emission, high color purity, etc.) based on the electronic transitions between the 4f energy levels. So in recent years, lanthanide complexes have been used as luminescent materials to prepare new luminescent devices, UV dosimeters and thin films for optical devices [5]. Organic ligands with chromophoric groups coordinated to the lanthainde ions could act as ‘antenna’, absorbing ultraviolet light and transferring energy to the ions [5a,6,7]. In this paper we report the synthesis of a series of carbosilane dendrimers functionalized with acetyl groups. Then lanthanide ions were conveniently introduced into the carbosilane dendrimers. And the fluorescence spectra of these complexes were recorded then. 1. Experimental According to literature [8] the system keeps anhydrous and oxygen-free in both Grignard reactions and hydrosilylation reactions. All manipulations in Grignard reactions and hydrosilylation reactions were carried out under argon atmosphere; and all solvents were dried and freshly distilled under argon prior to use. Synthetic route of carbosilane dendrimers G00 G02 with acetyl end-group is shown in Scheme 1. * Corresponding author. E-mail address: [email protected] (S.Y. Feng). 1001-8417/$ – see front matter # 2009 Sheng Yu Feng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2009.05.016
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W.Y. Sun et al. / Chinese Chemical Letters 20 (2009) 1085–1087
Scheme 1. Synthetic route of carbosilane dendrimers with acetyl end-group G00 G02 (n = 0, 1).
At 20 8C, to a solution of dendrimers with aminopropyl end-group in dry dichloromethane was added Et3N (1.5 equiv. to aminopropyl groups), and then CH3COCl (1.1 equiv. to aminopropyl groups) was slowly added. After stirred at 0 8C for 30 min, the mixture was washed with H2O, saturated NaHCO3 and brine, dried over Na2SO4, filtered and concentrated to give crude product, which was purified by silica column chromatography(MeOH:DCM = 0–5%, 1% Et3N) to give a yellow oil as desired compound. The dendrimers was dissolved in 10 mL solvent (n-hexane or tetrahydrofuran, respectively) with stirring and stoichiometreic proportion Ln(NO3)36H2O (Ln = Tb and Eu, respectively) were added into the solution. The mixture
Fig. 1. Luminescence spectra (a) G01 ; (b) complex of Tb3+ ions in n-hexane; (c) complex of Tb3+ ions in tetrahydrofuran; (d) complex of Eu3+ ions in tetrahydrofuran.
W.Y. Sun et al. / Chinese Chemical Letters 20 (2009) 1085–1087
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was agitated magnetically to achieve a single phase for 4 h. After the mixture was precipitated with volatilizing solvent in exsiccator, the solids were dissolved in solvent and precipitated again. The desired complex was dried in exsiccator at room temperature [9]. 2. Results and discussion Two catalysts were used, respectively, in the hydrosilylation reactions. When we used platinum(0)-1,3-divinyl1,1,3,3-tetramethyldisiloxane complex solution instead of chloroplantinic acid solution (in isopropanol) as catalyst in hydrosilylation, the dendrimers with aminopropyl end-group obtained are fully functionated except G0. All dendrimers have been characterized by 1H NMR, IR, and MS [10]. Fig. 1 is the luminescence spectra of G01 and three kinds of complexes. Carbosilane dendrimer G01 has hardly no emission in visible light region (curve a). Meanwhile, three complexes have narrow-width emission in visible light region. Curve b is the emission of complex of Tb3+ ions in n-hexane and curve c is the emission of complex of Tb3+ ions in tetrahydrofuran. Tetrahydrofuran and n-hexane were used as solvents in coordination, respectively. Compare curve b with curve c, the residual emission of carbosilane dendrimer could be monitored while they did not appeared in curve c. The results indicate that tetrahydrofuran is optimal solvent for carbosilane’s coordination because the coordination could promote the energy transfer from carbosiliane dendrimer to lanthanide ions. And the emission of complex of Eu3+ ions in tetrahydrofuran also shows excellent emission (curve d). Trace H2O in the system can quench the coordination. So anhydrous is the basic demand to assure coordination successfully. The Eu3+-dendrimers show strong red luminescence and Tb3+-dendrimers complexes show green luminescence with their emission maximum wavelengths around 617 and 548 nm in visible region, respectively. 3. Conclusions A new series of carbosilane dendrimers with acetyl end-group have been synthesized and the fundamental luminescent characteristics of their complexes with Eu3+ and Tb3+ have been investigated. It shows that the complexes of these dendrimers with lanthanide ions have narrow-width emission in visible light region. Further investigation on luminescent properties of these lanthanide ions-dendrimers complexes is undergoing. Acknowledgments This work was financially supported by the National Natural Science Foundation of China (Nos. 20574043, 20874057) and the Key Natural Science Foundation of Shandong Province of China (No. Z2007B02). References [1] [2] [3] [4] [5]
[6] [7] [8] [9] [10]
J.B. Arwin, M.J.L. Rob, Eur. J. Org. Chem. 2005 (2005) 487. J.S. Cho, A. Kimoto, M. Higuchi, K. Yamamoto, Macromol. Chem. Phys. 206 (2005) 635. J.A. Erick, O.G. Sergio, E.S. Eric, J. Polym. Sci. A: Polym. Chem. 43 (2005) 168. D.M. Xu, K.D. Zhang, X.L. Zhu, J. Appl. Polym. Sci. 104 (2007) 422. (a) N. Sabbatini, M. Guardigli, J.M. Lehn, Coord. Chem. Rev. 123 (1993) 201; (b) C.G. Gameiro, E.F. da Silva Jr., S. Alves Jr., G.F. de Sa´, P.A. Santa-Cruz, Mater. Sci. Forum 315–317 (1999) 249; (c) G.F. de Sa´, S. Alves Jr., B.J.P. da Silva, E.F. da Silva Jr., Opt. Mater. 11 (1998) 23; (d) S.P. Vila-Nova, G.A.L. Pereira, R.Q. Albuquerque, et al. J. Lumin. 109 (2004) 173. G.E. Buono-Core, H. Li, Coord. Chem. Rev. 99 (1990) 55. G. Crosby, R.E. Whan, R. Alire, J. Chem. Phys. 34 (1961) 743. C.F. Li, D.X. Li, S.Y. Feng, Polym. Int. 54 (2005) 1041. Z.H. Zhang, Y. Song, T. Okamura, Y. Hasegawa, W.Y. Sun, N. Ueyama, Inorg. Chem. 45 (2006) 2896. Data for compounds: G01 : Yields: 53.2%; 1H NMR (CDCl3, d ppm): 0.01–0.23 (m, 84H, Si–CH3), 0.41–0.65 (m, 24H, Si–CH2), 1.02–1.20 (m, 24H, Si–CH2), 1.29–1.60 (m, 30H, Si–CH2–CH2–CH2), 1.90 (s, 18H, CO–CH3), 2.40–2.62 (m, 12H, –CH2–NH), 10.21 (br s, 6H, –CH2–NH). MS: 1943.4. Anal. calcd. for C85H198 N6O12Si16: C 52.47, H 10.26, N 4.32, O 9.87; found C 52.45, H 10.22, N 4.34, O 9.93. G02 : Yields: 40.1%; 1 H NMR (CDCl3, d ppm): 0.00–0.25 (m, 174H, Si–CH3), 0.39–0.64 (m, 60H, Si–CH2), 1.19–1.30 (m, 48H, Si–CH2, Si–CH2–CH2–CH2), 1.40– 1.53 (m, 54H, Si–CH2–CH2), 1.90 (s, 36H, CO–CH3), 2.38–2.64 (m, 24H, –CH2–NH), 10.50 (br s, 6H, –CH2–NH). MS: 4098.2. Anal. calcd. for C181H420N12O24Si34: C 52.97, H 10.31, N 4.10, O 9.36; found C 52.95, H 10.30, N 4.12, O 9.39.
Chinese Chemical Letters 20 (2009) 1085–1087 www.elsevier.com/locate/cclet
Short communication
A series of carbosilane dendrimers with acetyl end-group: From synthesis to their unique optical characteristics Wen Yan Sun, Hai Feng Lu, Deng Xu Wang, Sheng Yu Feng * School of Chemistry and Chemical Engineering Shandong University, Ji’nan 250100, China Received 11 February 2009
Abstract A series of carbosilane dendrimers with acetyl end-group were synthesized. Their structures were characterized by 1H NMR, IR, and MS, respectively. Then dendrimers were coordinated with lanthanide ions (Eu3+ and Tb3+, respectively). The luminescence spectra of the complexes show narrow-width emissions in visible light region. # 2009 Sheng Yu Feng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Synthesis; Carbosilane dendrimer; Luminescence; Lanthanide ions
Carbosilane dendrimer is a novel class of macromolecules and could be widely used in the fields of medicinal chemistry, hostguest chemistry, and catalysis [1–4]. They are particularly suitable for preparing metal nanoparticles because of their monodispersity, regular and highly branched architecture, multiple surface functionality, and cavities in the structure. Some lanthanide ions, for example Eu3+ and Tb3+, possess good luminescence characteristics (visible light emission, high color purity, etc.) based on the electronic transitions between the 4f energy levels. So in recent years, lanthanide complexes have been used as luminescent materials to prepare new luminescent devices, UV dosimeters and thin films for optical devices [5]. Organic ligands with chromophoric groups coordinated to the lanthainde ions could act as ‘antenna’, absorbing ultraviolet light and transferring energy to the ions [5a,6,7]. In this paper we report the synthesis of a series of carbosilane dendrimers functionalized with acetyl groups. Then lanthanide ions were conveniently introduced into the carbosilane dendrimers. And the fluorescence spectra of these complexes were recorded then. 1. Experimental According to literature [8] the system keeps anhydrous and oxygen-free in both Grignard reactions and hydrosilylation reactions. All manipulations in Grignard reactions and hydrosilylation reactions were carried out under argon atmosphere; and all solvents were dried and freshly distilled under argon prior to use. Synthetic route of carbosilane dendrimers G00 G02 with acetyl end-group is shown in Scheme 1. * Corresponding author. E-mail address: [email protected] (S.Y. Feng). 1001-8417/$ – see front matter # 2009 Sheng Yu Feng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2009.05.016
1086
W.Y. Sun et al. / Chinese Chemical Letters 20 (2009) 1085–1087
Scheme 1. Synthetic route of carbosilane dendrimers with acetyl end-group G00 G02 (n = 0, 1).
At 20 8C, to a solution of dendrimers with aminopropyl end-group in dry dichloromethane was added Et3N (1.5 equiv. to aminopropyl groups), and then CH3COCl (1.1 equiv. to aminopropyl groups) was slowly added. After stirred at 0 8C for 30 min, the mixture was washed with H2O, saturated NaHCO3 and brine, dried over Na2SO4, filtered and concentrated to give crude product, which was purified by silica column chromatography(MeOH:DCM = 0–5%, 1% Et3N) to give a yellow oil as desired compound. The dendrimers was dissolved in 10 mL solvent (n-hexane or tetrahydrofuran, respectively) with stirring and stoichiometreic proportion Ln(NO3)36H2O (Ln = Tb and Eu, respectively) were added into the solution. The mixture
Fig. 1. Luminescence spectra (a) G01 ; (b) complex of Tb3+ ions in n-hexane; (c) complex of Tb3+ ions in tetrahydrofuran; (d) complex of Eu3+ ions in tetrahydrofuran.
W.Y. Sun et al. / Chinese Chemical Letters 20 (2009) 1085–1087
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was agitated magnetically to achieve a single phase for 4 h. After the mixture was precipitated with volatilizing solvent in exsiccator, the solids were dissolved in solvent and precipitated again. The desired complex was dried in exsiccator at room temperature [9]. 2. Results and discussion Two catalysts were used, respectively, in the hydrosilylation reactions. When we used platinum(0)-1,3-divinyl1,1,3,3-tetramethyldisiloxane complex solution instead of chloroplantinic acid solution (in isopropanol) as catalyst in hydrosilylation, the dendrimers with aminopropyl end-group obtained are fully functionated except G0. All dendrimers have been characterized by 1H NMR, IR, and MS [10]. Fig. 1 is the luminescence spectra of G01 and three kinds of complexes. Carbosilane dendrimer G01 has hardly no emission in visible light region (curve a). Meanwhile, three complexes have narrow-width emission in visible light region. Curve b is the emission of complex of Tb3+ ions in n-hexane and curve c is the emission of complex of Tb3+ ions in tetrahydrofuran. Tetrahydrofuran and n-hexane were used as solvents in coordination, respectively. Compare curve b with curve c, the residual emission of carbosilane dendrimer could be monitored while they did not appeared in curve c. The results indicate that tetrahydrofuran is optimal solvent for carbosilane’s coordination because the coordination could promote the energy transfer from carbosiliane dendrimer to lanthanide ions. And the emission of complex of Eu3+ ions in tetrahydrofuran also shows excellent emission (curve d). Trace H2O in the system can quench the coordination. So anhydrous is the basic demand to assure coordination successfully. The Eu3+-dendrimers show strong red luminescence and Tb3+-dendrimers complexes show green luminescence with their emission maximum wavelengths around 617 and 548 nm in visible region, respectively. 3. Conclusions A new series of carbosilane dendrimers with acetyl end-group have been synthesized and the fundamental luminescent characteristics of their complexes with Eu3+ and Tb3+ have been investigated. It shows that the complexes of these dendrimers with lanthanide ions have narrow-width emission in visible light region. Further investigation on luminescent properties of these lanthanide ions-dendrimers complexes is undergoing. Acknowledgments This work was financially supported by the National Natural Science Foundation of China (Nos. 20574043, 20874057) and the Key Natural Science Foundation of Shandong Province of China (No. Z2007B02). References [1] [2] [3] [4] [5]
[6] [7] [8] [9] [10]
J.B. Arwin, M.J.L. Rob, Eur. J. Org. Chem. 2005 (2005) 487. J.S. Cho, A. Kimoto, M. Higuchi, K. Yamamoto, Macromol. Chem. Phys. 206 (2005) 635. J.A. Erick, O.G. Sergio, E.S. Eric, J. Polym. Sci. A: Polym. Chem. 43 (2005) 168. D.M. Xu, K.D. Zhang, X.L. Zhu, J. Appl. Polym. Sci. 104 (2007) 422. (a) N. Sabbatini, M. Guardigli, J.M. Lehn, Coord. Chem. Rev. 123 (1993) 201; (b) C.G. Gameiro, E.F. da Silva Jr., S. Alves Jr., G.F. de Sa´, P.A. Santa-Cruz, Mater. Sci. Forum 315–317 (1999) 249; (c) G.F. de Sa´, S. Alves Jr., B.J.P. da Silva, E.F. da Silva Jr., Opt. Mater. 11 (1998) 23; (d) S.P. Vila-Nova, G.A.L. Pereira, R.Q. Albuquerque, et al. J. Lumin. 109 (2004) 173. G.E. Buono-Core, H. Li, Coord. Chem. Rev. 99 (1990) 55. G. Crosby, R.E. Whan, R. Alire, J. Chem. Phys. 34 (1961) 743. C.F. Li, D.X. Li, S.Y. Feng, Polym. Int. 54 (2005) 1041. Z.H. Zhang, Y. Song, T. Okamura, Y. Hasegawa, W.Y. Sun, N. Ueyama, Inorg. Chem. 45 (2006) 2896. Data for compounds: G01 : Yields: 53.2%; 1H NMR (CDCl3, d ppm): 0.01–0.23 (m, 84H, Si–CH3), 0.41–0.65 (m, 24H, Si–CH2), 1.02–1.20 (m, 24H, Si–CH2), 1.29–1.60 (m, 30H, Si–CH2–CH2–CH2), 1.90 (s, 18H, CO–CH3), 2.40–2.62 (m, 12H, –CH2–NH), 10.21 (br s, 6H, –CH2–NH). MS: 1943.4. Anal. calcd. for C85H198 N6O12Si16: C 52.47, H 10.26, N 4.32, O 9.87; found C 52.45, H 10.22, N 4.34, O 9.93. G02 : Yields: 40.1%; 1 H NMR (CDCl3, d ppm): 0.00–0.25 (m, 174H, Si–CH3), 0.39–0.64 (m, 60H, Si–CH2), 1.19–1.30 (m, 48H, Si–CH2, Si–CH2–CH2–CH2), 1.40– 1.53 (m, 54H, Si–CH2–CH2), 1.90 (s, 36H, CO–CH3), 2.38–2.64 (m, 24H, –CH2–NH), 10.50 (br s, 6H, –CH2–NH). MS: 4098.2. Anal. calcd. for C181H420N12O24Si34: C 52.97, H 10.31, N 4.10, O 9.36; found C 52.95, H 10.30, N 4.12, O 9.39.