A new water-soluble pillar[5]arene: synthesis and application in the preparation of gold nanoparticles Yong Yao, a Min Xue, a Xiaodong Chi, a Yingjie Ma, a Jiuming e, b Zeper Abliz, b and Feihe uang a, * a Department of Chemistry, Zhejiang University, angzhou 310027, P. R. China, and Fax: +86-571- 8795-1895; Tel: +86-571-8795-3189; Email address: fhuang@zju.edu.cn. b Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China. Electronic Supplementary Information (23 pages) 1. Materials and methods S2 2. Syntheses of pillar[5]arene 1 and noncyclic monomeric analog 4 S2 3. Synthesis and characterization of pillar[5]arene-stabilized gold nanoparticles S12 4. Catalytic reduction of 4-nitroaniline S17 S1
1. Materials and methods 1,4-Bis(2-hydroxyethoxy)benzene, triphenylphosphine, carbon tetrabromide, boron trifluoride etherate and -methylimidazole were reagent grade and used as received. Solvents were either employed as purchased or dried according to procedures described in the literatures. 1 MR spectra were collected on a Varian Unity IVA-400 spectrometer (uker) with internal standard TMS. 13 C MR spectra were recorded on a Varian Unity IVA-400 spectrometry at 100 Mz. Mass spectra were obtained on a uker Esquire 3000 plus mass spectrometer (uker-franzen Analytik Gmb emen, Germany) equipped with an ESI interface and an ion trap analyzer. RMS were obtained on a uker 7-Tesla FT-ICRMS equipped with an electrospray source (Billerica, MA, USA). The melting points were collected on a SPSIC WRS-2 automatic melting point apparatus. 2. Syntheses of pillar[5]arene 1 and noncyclic monomeric analog 4 Scheme S1. Synthetic route for compound 1 C 4 /PPh 3 C 3 C (C 2 ) n BF 3 Et 2 (C 2 Cl) 2 5 Toluene 5 2 3 10 1 S2
2.1. Synthesis of compound 2 S1,S2 A solution of 1,4-bis(2-hydroxyethoxy)benzene (10.0 g, 50.4 mmol) and triphenylphosphine (31.5 g, 120 mmol) in dry acetonitrile (250 ml) was cooled with an ice bath. Under vigorous stirring, carbon tetrabromide (39.8 g, 120 mmol) was slowly added. The mixture was stirred at room temperature for 4 hours. Then cold water (200 ml) was added to the reaction mixture to give white precipitation. The precipitate was collected, washed with methanol/water (3:2, 3 100 ml), recrystallized from methanol, and dried under vacuum to afford 2 as white crystals (14.5 g, 94%). The 1 MR spectrum of 2 is shown in Figure S1. 1 MR (400 Mz, CDCl 3, rt) δ (ppm): 6.86 (s, 4), 4.25 (t, J = 6.3 z, 4), 3.62 (t, J = 6.8 z, 4). CDCl 3 Fig. S1. 1 MR spectrum (400 z, CDCl 3, rt) of compound 2. S3
2.2. Synthesis of compound 3 S1 (C 2 ) n BF 3 Et 2 (C 2 Cl) 2 5 2 3 A solution of 2 (3.37 g, 11.5 mmol) and paraformaldehyde (0.349 g, 11.5 mmol) in 1,2-dichloroethane (50 ml) was cooled with ice bath. Boron trifluoride etherate (3.26 g, 23.0 mmol) was added to the solution and the mixture was stirred at room temperature for 1 hour. The reaction mixture was then washed with water (2 50 ml) and dried with a 2 S 4. The solvent was evaporated to provide a crude product, which was purified by column chromatography (eluent: petroleum ether/ethyl acetate, 100:1) to afford a white solid (2.0 g, 52%). Mp: 93.2 95.8 ºC. The 1 MR spectrum of 3 is shown in Figure S2. 1 MR (400 Mz, CDCl 3, rt) δ (ppm): 6.93 (s, 10), 4.24 (t, J = 5.7 z, 20), 3.86 (s, 10), 3.65 (t, J = 5.6 z, 20). CDCl 3 Fig. S2. 1 MR spectrum (400 Mz, CDCl 3, rt) of compound 3. S4
2.3. Synthesis of compound 1 5 Toluene 5 3 10 1 A mixture of 3 (1.68 g, 1.00 mmol) and -methylimidazole (1.64 g, 20.0 mmol) in toluene (25 ml) was stirred in a 100 ml round-bottom flask at 120 ºC for 24 hours. After cooling, the solvent was removed and the residue was recrystallized from ethanol/diethyl ether (1:2) to give a white solid (2.1 g, 91%). Mp: 122.3 124.5 ºC. The 1 MR spectrum of 1 is shown in Figure S3. 1 MR (400 Mz, DMS-d 6, rt) δ (ppm): 8.78 (s, 10), 7.70 (s, 10), 7.43 (s, 10), 6.72 (s, 10), 4.60 (s, 20), 4.27 (s, 20), 3.74 (s, 30), 3.52 (s, 10). The 13 C MR spectrum of 1 is shown in Figure S4. 13 C MR (100 Mz, DMS-d 6, rt) δ (ppm): 149.02, 137.02, 128.41, 122.84, 118.19, 114.53, 66.69, 49.34, 40.01, 36.02, 28.84. RESIMS is shown in Figure S5: m/z of [M 2] 2+ C 95 121 10 20 8 1170.65; [M 3] 3+ C 95 121 10 20 7 754.13; [M 4] 4+ C 95 121 10 20 6 545.37; [M 5] 5+ C 95 121 10 20 5 420.51; [M 6] 6+ C 95 121 10 20 4 336.94; [M 7] 7+ C 95 121 10 20 3 277.53. S5
5 10 D 2 DMS Figure S3. 1 MR spectrum (400Mz, DMS-d 6, rt) of 1. Fig. S4. 13 C MR spectrum (100Mz, DMS-d 6, rt) of 1. S6
100 Relative Intensity [M 2] 2+ 1170.6495 50 0 1165 1170 1175 m/z 100 Relative Intensity [M 3] 3+ 754.1270 50 0 752.0 754.0 756.0 758.0 m/z 100 Relative Intensity 545.3660 [M 4] 4+ 50 0 544.0 546.0 548.0 m/z S7
100 Relative Intensity 420.5093 [M 5] 5+ 50 0 420.0 421.0 422.0 m/z 100 Relative Intensity [M 6] 6+ 336.9382 50 0 336.0 336.5 337.0 337.5 338.0 m/z 100 Relative Intensity 277.5302 [M 7] 7+ 50 0 277.0 277.5 278.0 278.5 m/z Fig. S5. igh resolution electrospray ionization mass spectrum of 1. S8
2.4 Synthesis of noncyclic monomeric analog 4 Toluene 2 2 4 A mixture of 2 (1.68 g, 5.00 mmol) and -methylimidazole (1.64 g, 20.0 mmol) in toluene (25 ml) was stirred in a 100 ml round-bottom flask at 120 ºC for 24 h. After cooling, the solvent was removed and the residue was recrystallized from ethanol/diethyl ether (1:2) to give a white solid (2.3 g, 96%). Mp: 98.7 99.4 ºC. The 1 MR spectrum of 4 is shown in Figure S6. 1 MR (400 Mz, D 2, rt) δ (ppm): 8.74 (s, 2), 7.50 (s, 2), 7.37 (s, 2), 6.88 (s, 4), 4.51 (t, J = 4.0 z, 4), 4.33 (t, J = 4.0 z, 4), 3.82 (s, 6). The 13 C MR spectrum of 4 is shown in Figure S7. 13 C MR (100 Mz, DMS-d 6, rt) δ (ppm): 152.11, 136.33, 123.38, 122.49, 115.97, 66.60, 48.84, 35.63. LRESIMS is shown in Figure S8: m/z 640.0 [M 2] 2+. RESIMS is shown in Figure S9: m/z calcd for [M ] + C 18 4 2 24, 407.1077; found 407.1077. 1.96 1.95 1.97 4.01 4.01 4.02 6.00 8.74 7.50 7.37 6.88 4.68 4.51 4.34 4.33 4.32 3.82 D 2 2 9.0 8.6 8.2 7.8 7.4 7.0 6.6 6.2 5.8 5.4 5.0 4.6 f1 (ppm) Fig. S6. 1 MR spectrum (400Mz, D 2, rt) of 4. 4.2 3.8 S9
152.11 136.33 123.38 122.49 115.97 66.60 48.84 35.63 155 145 135 125 115 105 95 90 85 80 75 70 65 60 55 f1 (ppm) Fig. S7. 13 C MR spectrum (100Mz, D 2, rt) of 4. 50 45 40 35 30 Fig. S8. Electrospray ionization spectrum of 4. Assignment of the main peak: m/z 164.0 [M 2] 2+. S10
1.2e+07 407.1077 1.1e+07 [M ] + 1.0e+07 9.0e+06 8.0e+06 7.0e+06 PULPRG se curr_pp TD 524288 S 8 DS 0 SW 1891532.285 ppm 6.0e+06 5.0e+06 4.0e+06 3.0e+06 2.0e+06 1.0e+06 0.0e+00 406.2 406.7 407.2 407.7 408.2 m/z /Data/gc/120310/YYD/pdata/1 Administrator Thu Mar 15 16:50:03 2012 Fig. S9. igh resolution electrospray ionization mass spectrum of 4. S11
3. Synthesis and characterization of pillar[5]arene-stabilized gold nanoparticles 3.1. Synthesis of gold nanoparticles - The GPs were synthesized by the reduction of AuCl 4 ions in the aqueous dispersions of 1. In a typical experiment, an aqueous solution of AuCl 4 (0.10 ml, 9.7 mm) was added to an aqueous solution of 1 (2.7 ml, 10 1 mm). Then aqueous sodium borohydride (0.20 ml, 0.0125 g/ml) was injected into the above solution under vigorous stirring. The solution became wine red, indicating that pillar[5]arene-stabilized gold nanoparticles were immediately obtained. 3.2 Characterization of gold nanoparticles Fig. S10. UV/Vis spectra of gold nanoparticles stabilized by pillar[5]arene 1 at different concentrations: a, 2 μm; b, 4 μm; c, 10 μm; d, 50 μm; e, 200 μm. S12
10 nm Fig. S11. TEM image and size histogram of gold nanoparticles stabilized by 1 at a concentration of 200 μm. S13
10 nm Fig. S12. TEM image and size histogram of gold nanoparticles stabilized by 1 at a concentration of 50 μm. S14
10 nm Fig. S13. TEM image and size histogram of gold nanoparticles stabilized by 1 at a concentration of 10 μm. S15
10 nm Fig. S14. TEM image and size histogram of gold nanoparticles stabilized by 1 at a concentration of 2 μm. S16
Electronic Supplementary Material (ESI) for Chemical Communications 80 60 (222) (311) (220) (200) Relative Intensity (a.u.) (111) 100 40 30 40 50 60 70 80 2θ (degree) Fig. S15. XRD pattern of gold nanoparticles. Fig. S16. igh-resolution TEM image of gold nanoparticles stabilized by pillar[5]arene 1 with a concentration of 200 μm (scale bar: 2 nm). 4. Catalytic reduction of 4-nitroaniline The catalytic reduction of 4-nitroaniline was studied as follows. To a standard quartz cell with a 1-cm path length and about 4 ml volume, 3 ml of 0.20 mm 4-nitroaniline and 0.03 g of ab4 (much more excess) were added. Then the addition of 0.01 ml of 2.0 10 3 mm gold nanoparticles to the mixture caused the decrease in the intensity of the absorption of 4-nitroaniline. The absorption spectra were recorded every 2 minutes in a scanning range of 200 700 at room temperature. The control experiment was also carried out using a mixture of ab4 and 4-nitroaniline. S17
Abs (a.u.) 1.5 1.0 0.5 a: 0 s b: 80 s c: 160 s d: 242 s e: 320 s 0.0 200 300 400 500 Wavelength (nm) 1 0 Ln (A) -1-2 0 80 160 240 320 t (s) Fig. S17. The successive UV/Vis absorption of the reduction of 4-nitroaniline and plot of ln(a) against time by excess ab 4 in the presence of pillar[5]arene-stabilized gold nanoparticles with an average size of 1.88 ± 0.58 nm. S18
Abs (a.u.) 1.5 1.0 0.5 0 s 81 s 162 s 242 s 328 s 410 s 0.0 200 300 400 500 Wavelength (nm) 0.5 0.0 Ln (A) -0.5-1.0-1.5-50 0 50 100 150 200 250 300 350 t (s) Fig. S18. The successive UV/Vis absorption of the reduction of 4-nitroaniline and plot of ln(a) against time by excess ab 4 in the presence of pillar[5]arene-stabilized gold nanoparticles with an average size of 3.09 ± 0.79 nm. S19
Abs (a.u.) 2.0 1.5 1.0 0.5 0 s 76 s 158 s 238 s 320 s 401 s 483 s 569 s 670 s 780 s 910 s 0.0 200 300 400 500 Wavelength (nm) 0.5 0.0-0.5 Ln (A) -1.0-1.5-2.0 0 100 200 300 400 500 600 700 800 t (s) Fig. S19. The successive UV/Vis absorption of the reduction of 4-nitroaniline and plot of ln(a) against time by excess ab 4 in the presence of pillar[5]arene-stabilized gold nanoparticles with an average size of 3.86 ± 0.91 nm. S20
2.5 2.0 Abs (a.u.) 1.5 1.0 0.5 0.0 200 300 400 500 Wavelength (nm) 0.6 0.4 Ln (A) 0.2 0.0-0.2-0.4 0 200 400 600 800 1000 1200 1400 t (s) Fig. S20. The successive UV/Vis absorption of the reduction of 4-nitroaniline and plot of ln(a) against time by excess ab 4 in the presence of pillar[5]arene-stabilized gold nanoparticles with an average size of 5.95 ± 1.64 nm. S21
Tab. S1. Au nanoparticles as catalysts for the borohydride reduction of nitro-compounds Catalyst Mole ratio (AuCl/nitro-compound) Au nanoparticles 0.2% itro-compound 2 Reaction rate References constant 7.36 10 3 S 1 S3 Au@Si 2 core-shell particles 50% 2 4.6 10 4 S 1 S4 Road-Shaped Gold anorattles 0.5% 2 < 10 2 S 1 S5 Au anocrystals 18% 2 6.54 10 3 S 1 S6 Au nanoparticles 1% This work 0.08% 2 2 2 2 (o, m, p) 2 < 5 10 3 S 1 S7 8.34 10 3 S 1 B 4 ia ia Dab = gold nanoparticle, ia = nitroaniline, Dab = 1,4-diaminobenzene Fig. S21. Mechanistic model of the reduction of 4-nitroaniline. S22
5. References: S1. Y. Ma, X. Ji, F. Xiang, X. Chi, C. an, J. e, Z. Abliz, W. Chen and F. uang, Chem. Commun., 2011, 47, 12340 12342. S2. M. R. Pinto, B. M. Kristal and K. S. Schanze, Langmuir, 2003, 19, 6523 6533. S3. Y. Gao, X. Ding, Z. Zheng, X. Cheng and Y. Peng, Chem. Commun., 2007, 3720 3722. S4. B. J. Lee, J. C. Park and. Song, Adv. Mater., 2008, 20, 1523 1528. S5. Y. Khalavka, J. Becker and C. Sonnichsen, J. Am. Chem. Soc., 2009, 131, 1871 1875. S6. J. Liu, G. Qin, P. Raveendran and Y. Ikushima, Chem. Eur. J., 2006, 12, 2131 2138. S7. Y. Yao, Y. Sun, Y. an and C. Yan, Chin. J. Chem., 2010, 28, 705 712. S23