A Rational Entry to Cyclic Polymers via Selective Cyclization by Self-Assembly and Topology Transformation of Linear Polymers

Transcription

1 A Rational Entry to Cyclic Polymers via Selective Cyclization by Self-Assembly and Topology Transformation of Linear Polymers Daisuke Aoki,*, Gouta Aibara, Satoshi Uchida, and Toshikazu Takata*,, Department of Chemical Science and Engineering, Tokyo Institute of Technology and JST-CREST, Ookayama, Meguro, Tokyo , Japan Table of Contents Materials, instuments, and Measurements S2 Synthesis of self-complementary monomer (1) S3-S4 Synthesis of Dimer-PCL_A S5 Synthesis of Dimer-PCL_U S6 Synthesis of Monomer-PCL n= S7 1 H-NMR spectrum of S8 MALDI-TOF-MS spectrum for S9 ESI-MS spectra for S10 1 H-NMR spectra of Dimer-PCL_A and Dimer-PCL_U S11 FTIR spectra of Dimer-PCL_A, Dimer-PCL_U, Dimer-PCL n=20 _A, and Dimer-PCL n=20 _U S12-S13 Calculation of the intrinsic viscosity ratio [η] Dimer-PCL_U / [η] Dimer-PCL_A S14 Attenuation curves of Dimer-PCL_A and Dimer-PCL_U S15 MALDI-TOF-MS spectrum for Monomer-PCL n= S16 1 H-NMR spectra and GPC profiles of Dimer-PCL n=20 _A and Dimer-PCL n=20 _U S17 DOSY spectra of Dimer-PCL n=20 _A and Dimer-PCL n=20 _U S18-S19 DSC curves of Dimer-PCL_A, Dimer-PCL_U, Dimer-PCL n=20 _A, and Dimer-PCL n=20 _U S20-S21 References S22 S1

2 Materials Dichloromethane was purchased from ASAHI GLASS CO., LTD., and distilled over CaH 2 under a nitrogen atmosphere after being washed with water. ε-caprolactone (99%, Tokyo Kasei Kogyo Co., Ltd. (TCI)) was distilled over CaH 2 under reduced pressure. Diphenyl phosphate (99%, TCI), 3,5-dimethylphenyl isocyanate (98%, TCI), and acetic anhydride (98%, SIGMA-ALDRICH) were used as received. Other commercially available regents and solvents were used as received. Instruments 1 H- (400 MHz) and 13 C (100 MHz) NMR spectra were recorded on a JEOL AL-400 spectrometer using CDCl 3 as the solvent, calibrated using residual undeuterated solvent and tetramethylsilane as the internal standard. The diffusion coefficient (D h ) measurements and DOSY spectra were measured with a Bruker DSX-300 NMR spectrometer and a Bruker AVANCEIIIHD500 spectrometer. 1 The LED method for DOSY measurement was used. Pulse program: ledbpgp2s, Diffusion time: 40 ms, Diffusion gradient length: 2000 us, Maximum gradient strength: 51 g/cm. 2 IR spectra were recorded on a JASCO FT/IR-230 spectrometer. Melting points were measured on a MELTING POINT APPARATUS SMP3 (Stuart Scientific) instrument. FAB and ESI HR-MS spectra were obtained at the Center for Advanced Material Analysis, Tokyo Institute of Technology on request. The size exclusion chromatography (GPC) was performed at 30 C in CHCl 3 (0.85 ml / min) using a JASCO PU-2080 system equipped with a set of a Shodex K-804 and a Shodex K-805 columns. The number average molecular weight (M n ), weight average molecular weight (M w ), and polydispersity index (M w /M n ) of the polymers were calculated on the basis of a polystyrene calibration. Preparative GPC was carried out using a HPLC LC-918 instrument by Japan Analytical Industry with a Megapak-Gel 201C. MALDI-TOF-MS were taken on a Shimadzu AXIMA-CFR mass spectrometer. The spectrometer was equipped with a nitrogen laser (I = 337 nm) and with pulsed ion extraction. The operation was performed at an accelerating potential of 20 kv by a linear-positive ion mode. The sample polymer solution (1 mg / ml) was prepared in CHCl 3, and the matrix, dithranol, and cationizing agent, sodium trifluoroacetate, were dissolved in CHCl 3 or THF (10 and 1 mg / ml, respectively). The polymer solution and the matrix solution were mixed, and 1 μl portion of the mixed solution was deposited onto a sample target plate and allowed to dry in the air at room temperature. Mass values were calibrated by the two-point method with insulin β plus H + at and R-cyanohydroxycinnamic acid dimer plus H + at Intrinsic viscosity [η] was measured by a conventional capillary viscometer of the Ubbelohde type. A water bath was used to maintain the temperature to 30.0 ºC. Five concentrations were used for each polymer and 3 measurements of S2

3 flow time were conducted for each concentration and average was used to determine the intrinsic viscosity. Synthesis of self-complementary monomer (1) Synthesis of imino ester S2 A mixture of monoformyl crown ether 3 (S1) (5.00 g, 10.5 mmol) and methyl 12-aminododecanoate hydrochloride 4 (3.05 g, 11.5 mmol) in toluene (120 ml) was refluxed for 12 h with a Dean-Stark trap. The toluene was removed under reduced pressure to afford imino ester (S2) as a colorless solid. The mixture was used for next step without further purification. Synthesis of amine S3 A solution of imino ester S2 (7.22 g, 10.5 mmol) in dry THF (200 ml) was added dropwise to a suspension of lithium aluminium hydride (1.94 g, 51.1 mmol) in dry THF (200 ml) at 0 C. The mixture was refluxed for 18 h. After addition of satd. aq. Na 2 SO 4 at 0 C, the precipitate formed was filtered off and the filtrate was evaporated in vacuo. The crude was purified by column chromatography eluting with EtOAc to give a precursor amine (S3) (4.65 g, 7.03 mmol, 67.0%) as colorless crystals. m.p ºC ; 1 H-NMR (400 MHz, CDCl 3, 298 K): δ (ppm) (m, 20H, alkyl), 2.60 (t, 2H, J = 6 Hz, -CH 2 N-CH 2 -), 3.66 (t, 2H, J = 6 Hz, -CH 2 -OH), 3.69 (s, 2H, -CH 2 -N-CH 2 -), (m, 8H, DB24C8-γ), (m, 8H, DB24C8-β), (m, 8H, DB24C8-α), (m, 7H, Ph); 13 C-NMR (100 MHz, CDCl 3, 298 K): δ (ppm) 26.0, 27.7, 29.7, 29.9, 30.4, 33.1, 49.8, 54.1, 63.4, 69.7, 69.9, 70.3, 71.64, 114.1, 114.2, 114.3, 121.1, 121.7, 149.2, 149.2; IR (KBr): 3417(broad), 2918, 2848, 1593, 1516, 1448, 1257, 1136, 1053, 960, 725 cm 1, FAB-MS (m/z): calcd for C 37 H 59 N 1 Na 1 O 9, ; found, S3

4 Synthesis of ammonium hexafluorophosphate 1 12 M hydrochloric acid (1.00 ml, 12.0 mmol) was added to a solution of the precursor amine S3 (1.60 g, 2.42 mmol) in the least dissolvable amount of methanol, and the reaction mixture was poured into a large amount of diethyl ether. The precipitate was collected by filtration and dried in vacuo. Satd. aq. ammonium hexafluorophosphate (1.63 g, 10.0 mmol) and then excess water were poured into the solution of obtained precipitate in the least amount of methanol until a precipitat formed. The precipitate was collected by filtration, washed with water, and dried in vacuo to give ammonium hexafluorophosphate 1 (1.12 g, 1.39 mmol, 57.4%) as colorless crystals. m.p ºC ; 1 H-NMR (400 MHz, CDCl 3, 298 K): δ (ppm) (m, 20H, alkyl), (m, -CH 2 NH + 2 PF 6 -CH 2 -, -CH 2 -OH-CH 2 -NH + 2 PF 6 -CH 2 -, DB24C8-γ, DB24C8-β and DB24C8-α), (m, 7H, Ph); 1 H NMR (500 MHz, DMSO-d 6, 298 K) δ (m, 16H), (m, 2H), (m, 2H), (br, 2H, -CH 2 NH + 2 PF 6 -CH 2 -), 3.38 (m, 2H, -CH 2 -OH), (d, J = 5 Hz, 8H, DB24C8-γ), (m, 8H, DB24C8-β), (m, 10H, DB24C8-α and -CH 2 -NH + 2 PF 6 -CH 2 -), (t, J = 5 Hz, 1H, -OH), (m, 7H, Ph), (br, 2H, NH + 2 ) ; 13 C-NMR (100 MHz, DMSO-d 6, 298 K): δ (ppm) 26.3, 26.5, 26.9, 29.5, 29.8, 29.9, 30.0, 30.1, 33.5, 47.3, 50.8, 61.7, 69.6, 69.8, 70.0, 70.1, 71.4, 114.4, 114.9, 116.3, 122.1, 123.9, 125.3, 149.1, 149.4, 149.9; IR (KBr): 3428(broad), 3178, 2925, 2854, 1729, 1593, 1506, 1454, 1255, 1103, 1057, 949, 843, 741, 557 cm 1. FAB-MS (m/z): calcd for [C 74 H 120 N 2 O 18 ] 2+, ; found, S4

5 Synthesis of Dimer-PCL_A A typical procedure for the polymerization of ε-cl initiated by [c2]-daisy-chain-type intermediate (2) shown in Scheme 1 is as follows: DPP (20.0 mg, 79.9 μmol) was added to a solution of initiator 2 (60.0 mg, 37.1 μmol) in CH 2 Cl 2 (8.00 ml) after sonication for 20 sec. ε-cl (0.25 g, 2.19 mmol) was then added to the solution to initiate the polymerization. After 24 h, excess 3,5-dimethylphenyl isocyanate (1.5 ml) was added to the solution and stirred for 24 h to introduce bulky end-cap groups at the termini of the polymer. The polymer was isolated by reprecipitation from CH 2 Cl 2 into ethanol / hexane = 1 / 9 (v / v) and purified by preparative gel permeation chromatography with CHCl 3 as the eluent to obtain dimer rotaxane-linked PCL Dimer-PCL_A (isolated: 0.12 g). In the case of the polymer having no bulky end-cap group at the termini Dimer-PCL-OH_A, the polymer was isolated by direct reprecipitation from solution in ethanol/hexane (1 / 9 : v / v) without the addition of excess 3,5-dimethylphenyl isocyanate. Yield, 61.0%; M n, NMR, 5,300 g / mol. 1 H NMR (400 MHz, CDCl 3, 298 K): δ (ppm), 1.38 (m, 2H n, (-CH 2 CH 2 CH 2 CH 2 CH 2 -) n ), 1.57 (m, 2H n, (-CH 2 CH 2 CH 2 O-) n ), 1.65 (m, 2H n, (-COCH 2 CH 2 CH 2 -) n ), 2.31 (t, 2H n, (-OCOCH 2 CH 2 -) n ), (m, 2H, -CH 2 NH + 2 PF 6 -CH 2 -), (m, 24H, DB24C8-γ, DB24C8-β and DB24C8-α), 4.06 (t, 2H n, (-CH 2 CH 2 O-) n ), (m, 2H, -CH 2 NH + 2 PF 6 -CH 2 -), (m, 13H, Ph). Dimer-PCL n=20 _A was prepared under similar conditions as above. DPP (0.457 g, 1.83 mmol) was added to a solution of initiator 2 (2.98 g, 1.84 mmol) in CH 2 Cl 2 (31.0 ml) after sonication for 20 sec. ε-cl (10.6 g, 92.9 mmol) was then added to the solution to initiate the polymerization. After 6 h, excess 3,5-dimethylphenyl isocyanate (6.80 ml) was added to the solution and stirred for 24 h to introduce bulky end-cap groups at the termini of the polymer. The polymer was isolated by reprecipitation from CH 2 Cl 2 into ethanol / hexane = 1 / 9 (v / v) and further purified by fractionation technique with CHCl 3 and hexane to obtain dimer rotaxane-linked PCL Dimer-PCL n=20 _A (isolated: 9.00 g). In the case of the polymer having no bulky end-cap group at the termini Dimer-PCL-OH n=20 _A, the polymer was isolated by reprecipitation from CH 2 Cl 2 in ethanol/hexane (1 / 9 : v / v) without the addition of 3,5-dimethylphenyl isocyanate. Yield, 74.3%; M n, NMR, 6,600 g / mol. S5

6 Synthesis of Dimer-PCL_U A typical procedure for the acetylation of obtained polymer is as follows: In a screw-capped test tube, Dimer-PCL_A (110 mg, 24.4 μmol), acetic anhydride (110 mg, 1.08 mmol), and triethylamine (210 mg, 2.08 mmol) in THF (3.0 ml) were stirred for 24 h at 40 ºC. The solution was diluted with CH 2 Cl 2 and washed with brine, dried over magnesium sulfate, evaporated in vacuo, and purified by preparative GPC with CHCl 3 as the eluent to obtain Dimer-PCL_U (isolated: 90 mg) as a red solid. Yield, 81.8%; M n, NMR, 5,100 g / mol. 1 H NMR (400 MHz, CDCl 3, 298 K): δ (ppm), 1.38 (m, 2H n, (-CH 2 CH 2 CH 2 CH 2 CH 2 -) n ), 1.57 (m, 2H n, (-CH 2 CH 2 CH 2 O-) n ), 1.65 (m, 2H n, (-COCH 2 CH 2 CH 2 -) n ), 2.31 (t, 2H n, (-OCOCH 2 CH 2 -) n ), (m, 2H, ArCH 2 NAcCH 2 ), (m, 24H, DB24C8-γ, DB24C8-β and DB24C8-α), 4.06 (t, 2H n, (-CH 2 CH 2 O-) n ), 4.40 and 4.59 (s, 2H, ArCH 2 NAc), (m, 13H, Ph). Dimer-PCL n=20 _U was synthesized under similar conditions as above, using Dimer-PCL n=20 _A instead of Dimer-PCL_A. In a recovery flask, Dimer-PCL n=20 _A (8.00 g, 1.21 mmol), acetic anhydride (11.7 g, 115 mmol), and triethylamine (23.1 g, 228 mmol) in THF (10.0 ml) was added to stir for 2 d at 50 ºC. The solution was diluted with CH 2 Cl 2 and washed with brine, dried over magnesium sulfate, evaporated in vacuo, and purified by reprecipitation from CHCl 3 into ethanol / hexane = 1 / 9 (v / v) to obtain Dimer-PCL n=20 _U (isolated: 7.30 g, yield: 94 %) as a pale yellow solid. Yield, 94.1%; M n, NMR, 6,400 g / mol. 1 H NMR (400 MHz, CDCl 3, 298 K): δ (ppm), 1.38 (m, 2H n, (-CH 2 CH 2 CH 2 CH 2 CH 2 -) n ), 1.57 (m, 2H n, (-CH 2 CH 2 CH 2 O-) n ), 1.65 (m, 2H n, (-COCH 2 CH 2 CH 2 -) n ), 2.31 (t, 2H n, (-OCOCH 2 CH 2 -) n ), (m, 2H, ArCH 2 NAcCH 2 ), (m, 24H, DB24C8-γ, DB24C8-β and DB24C8-α), 4.06 (t, 2H n, (-CH 2 CH 2 O-) n ), 4.40 and 4.59 (s, 2H, ArCH 2 NAc), (m, 13H, Ph). S6

7 Synthesis of Monomer-PCL n=20 In a screw-capped test tube, Dimer-PCL_OH n=20 _A (370 mg, 58.7 μmol) which was prepared by direct precipitation of the polymerization solution for the synthesis of Dimer-PCL n=20 _A into ethanol/hexane (1/9, v/v) prior to adding the end-capping agent, acetic anhydride (2.94 g, 28.8 mmol), and triethylamine (5.46 g, 54.0 mmol) in THF (21.6 ml) were stirred for 2 d at 50 ºC. The solution was diluted with CH 2 Cl 2 and washed with brine, dried over magnesium sulfate, evaporated in vacuo, and purified by preparative GPC with CHCl 3 as the eluent to obtain Monomer-PCL n=20 (isolated: 240 mg) as a red solid. Yield, 65.9 %; M n, NMR, 3,600 g / mol. 1 H NMR (400 MHz, CDCl 3, 298 K): δ (ppm), 1.38 (m, 2H n, (-CH 2 CH 2 CH 2 CH 2 CH 2 -) n ), 1.57 (m, 2H n, (-CH 2 CH 2 CH 2 O-) n ), 1.65 (m, 2H n, (-COCH 2 CH 2 CH 2 -) n ), (m, 6H, -N(C=O)CH 3 ), 2.31 (t, 2H n, (-OCOCH 2 CH 2 -) n ), (m, 2H, ArCH 2 NAcCH 2 ), (m, 8H, DB24C8-γ), (m, 8H, DB24C8-γ), (m, 8H, DB24C8-β), 4.06 (t, 2H n, (-CH 2 CH 2 O-) n ), (m, 8H, DB24C8-α), 4.40 and 4.59 (s, 2H, ArCH 2 NAc), (m, 7H, Ph). S7

8 Figure S1. 1 H-NMR spectra of (a) S3 and (b) 2 (400 MHz, CDCl 3, 298 K). Figure S2. 1 H-NMR spectrum of 2 (1) (500 MHz, DMSO-d 6, 298 K). S8

9 Figure S3. MALDI-TOF-MS spectrum for 2. S9

10 Figure S4. ESI-MS spectra for (a) 2, (b) enlarged view, and (c) calculated spectra for [2] 2+ (eluent: CHCl 3 ). S10

11 Figure S5. 1 H-NMR spectra of (a) Dimer-PCL_A and (b) Dimer-PCL_U (400 MHz, CDCl 3, 298 K). S11

12 Figure S6. FTIR Spectrum of Dimer-PCL_A (KBr). Figure S7. FTIR Spectrum of Dimer-PCL_U (KBr). S12

13 Figure S8. FTIR Spectrum of Dimer-PCL n=20 _A (KBr). Figure S9. FTIR Spectrum of Dimer-PCL n=20 _U (KBr). S13

14 5 Calculation of the intrinsic viscosity ratio [η] Dimer-PCL_U / [η] Dimer-PCL_A According to theories of SEC universal calibration, the polymers of different families with the same retention time possess the same hydrodynamic volume, indicating [η] PS M PS = [η] PCL M PCL (1) where [η] PS and [η] PCL are the intrinsic viscosity of the hypothetic monodisperse sample. For polystyrene (PS) in CHCl 3 at 30 ºC, can be calculated using [η] PS = K M a PS = M PS (2) With assigning the M n value based on the PS standards (M dimer-pcl_u = 7.5 kda and M dimer-pcl_a = 8.6 kda) obtained by the SEC analysis to the M PS in eq.2, and the combination of eq.1 and eq.2 lead to the following equation. [η] dimer-pcl_u M dimer-pcl_u = , ,500 [η] dimer-pcl_a M dimer-pcl_a = , ,600 M dimer-pcl_a M dimer-pcl_a The ratio of intrinsic viscosity [η] Dimer-PCL_U / [η] Dimer-PCL_A is [η] Dimer-PCL_U / [η] Dimer-PCL_A = ( , ,500) / ( , ,600) = 0.78 Figure S10. GPC profiles for Dimer-PCL_A and Dimer-PCL_U, and calculation method for [η] Dimer-PCL_U / [η] Dimer-PCL_A. S14

15 Figure S11. Attenuation curves of Dimer-PCL_A (Δ) and Dimer-PCL_U ( ) with deuterated chloroform as solvent. 1 Table S1. Diffusion coefficient (D diff ) and hydrodynamic radius (R H ) of resulting polymers. Polymer D diff (m 2 /s) R H (nm) Dimer-PCL_A Dimer-PCL_U Dimer-PCL n=20 _A Dimer-PCL n=20 _U R H (nm) was calculated using the Stokes-Einstein equation : R H = k B T/6πηD diff (k B = m 2 kgs -2 K -1, T=303 k, η= Pa s) S15

16 Figure S12. MALDI-TOF-MS spectrum for the decomposition product by the acetylation of Dimer-PCL-OH n=20 _A. S16

17 Figure S13. 1 H-NMR spectra of (a) Dimer-PCL n=20 _A, (b) Dimer-PCL n=20 _U, and (c) Monomer-PCL n=20 (500 MHz, CDCl 3, 298 K). Figure S14. GPC profiles for (a) Dimer-PCL n=20 _A, (b) Dimer-PCL n=20 _U, and (c) Monomer-PCL n=20 (eluent, CHCl 3 ; 30 ºC; detected by RI). S17

18 Figure S15. DOSY spectrum of Dimer-PCL n=20 _A (500 MHz, CDCl 3, 298 K). S18

19 Figure S16. DOSY spectrum of Dimer-PCL n=20 _U (500 MHz, CDCl 3, 298 K). S19

20 Figure S17. DSC curve of Dimer-PCL_A. Figure S18. DSC curve of Dimer-PCL_U. S20

21 Figure S19. DSC curve of Dimer-PCL n=20 _A. Figure S20. DSC curve of Dimer-PCL n=20 _U. S21

22 References (1) Kamiguchi, K.; Kuroki, S.; Satoh, M.; Ando, I. Macromolecules 2009, 42, 231. (2) Wu, D. H.; Chen, A. D.; Johnson, C. S. J. Magn. Reson. A. 1995, 115, 260. (3) Aoki, D.; Uchida, S.; Takata, T. ACS Macro Lett. 2014, 3, 324. (4) Aoki, D.; Uchida, S.; Nakazono, K.; Koyama, Y.; Takata, T. ACS Macro Lett. 2013, 2, 461. (5) Ogawa, T.; Nakazono, K.; Aoki, D.; Uchida, S.; Takata, T. ACS Macro Lett. 2015, 4, 343. S22