Cyclopolymerization to synthesize conjugated polymers containing ...
Supplementary Information
Cyclopolymerization to synthesize conjugated polymers containing Meldrum’s acid as a precursor for ketene functionality
Jeongeun Kim, Eun-Hye Kang and Tae-Lim Choi★
Department of Chemistry, Seoul National University, Seoul, 151-747, Korea
Tae-Lim Choi [email protected] ,
1
General experimental All reactions were carried out under dry argon atmospheres using standard Schlenk-line techniques. All reagents which are commercially available were used without further purification. 5-norbornene-endo-2,3dicarboxylic anhydride was purchased from Tokyo Chemical Industry, followed by thermal isomerization to the exo-form. Solvents for monomer synthesis were also commercially obtained: tetrahydrofuran (THF) was anhydrous (≥ 99.9%) grade from Sigma-Aldrich®. For polymerization, THF was distilled from sodium and benzophenone. THF was degassed for 10 minutes before using on polymerization. Thin-layer chromatography (TLC) was carried out on MERCK TLC silica gel 60 F254 and flash column chromatography was performed using MERCK silica gel 60 (0.040~0.063 mm). 1H NMR and
13
C NMR were recorded by
Varian/Oxford As-500 (500 MHz for 1H and 125 MHz for 13C) spectrometers. UV–vis spectra were measured by Jasco Inc. UV/vis-Spectrometer V-550. Gel permeation chromatography (GPC) for polymer molecular weight analysis was carried out with Waters system (1515 pump, 2414 refractive index detector and 2489 UV detector) and Shodex GPC LF-804 column eluted with THF (GPC grade, Honeywell Burdick & Jackson). Flow rate was 1.0 mL/min and temperature of column was maintained at 35 °C. Samples in 0.5-1.0 mg/mL THF were filtered by 0.2-µm PTFE filter before injection. Gel permeation chromatography (GPC) for polymer molecular weight analysis was carried out with Waters system (515 HPLC pump and 2410 refractive refractive index detector), Acme 9000 UV/Vis detector, and Shodex GPC LF-804 column eluted CHCl3 (HPLC grade, J. T. Baker). Flow rate was 0.8 mL/min and temperature of column was maintained at 35 °C. Samples in 0.5-1.0 mg/mL CHCl3 were filtered by 0.2-µm PTFE filter before injection. High resolution mass spectroscopy (HRMS) analyses were performed by the National Center for Inter-University Research Facility. Multimode 8 and Nanoscope Ⅴ controller (Veeco Instrument) were used for AFM imaging. Dynamic Light Scattering (DLS) data were obtained by Malvern Zetasizer Nano ZS.
Experimental procedure for monomer synthesis (1-3) 2,2-dimethyl-5,5-di(prop-2-ynyl)-1,3-dioxane-4,6-dione (1) O
O O O
This monomer was prepared by the modified method from the previous literature (Jin, S.-H.; Cho, H.-N.; Choi, S.-K. J. Polym. Sci. Polym. Chem. Ed., 1993, 31, 69.). Meldrum’s acid (2,2-dimethyl-1,3-dioxane-4,6-dione) (720.7 mg, 5 mmol) and K2CO3 (99%) (1.728 g, 12.5 mmol) in acetone was prepared in RBF purged with argon. Propargyl bromide (80 wt%, in toluene) (1.23 ml, 11 mmol) was dropwised and stirred for 10 hours with reflux. The mixture was filtered and evaporated, then organic layer was extracted with ethyl acetate (75 mL * 2). The organic layer was dried with MgSO4 and concentrated to give a yellow colored liquid. It was purified by recrystallization with dichloromethane and hexane to afford compound 1 as a white crystalline. 2
(719.7 mg, 3.273 mmol, 65.5 %). 1H-NMR and
13
C-NMR data are also available in the same literature.
HRMS (CI+): calcd. for C12H13O4, 221.0814, found, 221.0815.
Dihexyl dipropargylmalonate (2) O
O
O
O
This monomer was prepared by the same method from the previous literature (Kang, E.-H.; Lee, I, S.; Choi, T.-L. J. Am. Chem. Soc. 2011, 133, 11904.). 1H-NMR,
13
C-NMR and MS analysis data are also available in
the same literature.
N-propyl-exo-norbornene-5,6-dicarboximide (3)
O N O
This monomer was prepared by slightly modified method from the previous literature (Meijer, A.; Otto, S.; Engbert, Jan B. F. N. J. Org. Chem., 1998, 63, 8989.). 1H-NMR,
13
C-NMR and MS analysis data are also
available in the same literature.
Preparation of catalyst nd
2
generation Grubbs catalyst (51.8 mg, 0.0610 mmol) and 3-chloropyridine (1 mL) were mixed in 20-ml
sized vial for 5 minutes. Cold n-pentane was poured to the vial. After storage in freezer a few hours, the 3rd generation Grubbs catalyst was filtered and washed by pentane. The green product (39.1 mg, 0.0491 mmol, 80.5%) was vacuum dried and stored in desiccator.
General polymerization procedure Random copolymerization Monomers (0.1-0.05 mmol) with the given ratios in the table 1 were weighed in a 4-ml sized screw-cap vial with septum and purged with argon. Distilled and degassed solvent (0.2 mL) was added to the vial which was placed in a cold ice bath. The solution of initiator (0.1 mL) was added at once under vigorous stirring. 3
After confirming the monomer conversion by TLC, the reaction was quenched by excess ethyl vinyl ether. The concentrated reaction mixture of poly(3)-ran-poly(1) was precipitated by methanol/isopropylalcohol 1:2 mixture and poly(2)-ran-poly(1) was precipitated by methanol. The obtained solid was dried in vacuo Reactivity ratio: To determine reactivity ratio, we used Fineman-Ross method. Mixed monomers with the ratios of [3]:[1] = 90:10, 75:25, 60:40, 45:55, and 30:70 were prepared, then the catalyst was injected at 0 °C. To obtain the ratio of incorporated monomers in early stage, the reaction was quenched after 5 seconds, and the incorporated ratios were obtained from 1H NMR analysis.
[3]/[cat]
[1]/[cat]
f1
F1
90
10
0.9
0.856
-13.6
-7.489
75
25
0.75
0.582
-6.455
-0.848
60
40
0.6
0.441
-2.853
0.402
45
55
0.45
0.277
-1.745
1.314
30
70
0.3
0.190
-0.781
1.394
Using the Fineman-Ross equation below, r1 and r3 was obtained:
Arranged Fineman-Ross equation :
f1 vs F1
vs
From the result, we obtained the values of r1 = 0.7, r3=2.5 suggesting statistical copolymer.
4
Block copolymerization Monomer for the 1st block (0.1 mmol) was weighed in a 4-ml sized screw-cap vial with septum and purged with argon. Anhydrous and degassed solvent (0.1 mL) was added to the vial. The vial was placed in a cold ice bath. The solution of initiator (0.1 mL) was added at once under vigorous stirring. After confirming the monomer conversion by TLC, the solution of 1 (0.2 mL) was added to the vial. After the solution became viscous, the reaction mixture was put in room temperature for 1 hour to assure the full conversion of 1. The reaction was quenched by excess ethyl vinyl ether and diluted by chloroform to make homogeneous polymer solution.
The
con-centrated
reaction
mixture
of
poly(3)-b-poly(1)
was
precipitated
by
methanol/Isopropylalcohol 1:2 mixture and poly(2)-b-poly(1) was precipitated by methanol. The obtained solid was dried in vacuo
Atomic Force Microscopy (AFM) The atomic force microscopy experiments were performed with a thin film prepared by spin-coating of one drop of the polymer solution (~0.01 mg/ml, CHCl3, spinning rate = 2000 rpm for 30 sec.). The polymer solution was filtered by 0.2-µm PTFE filter before spin-coating. The thin films were prepared on mica. Images ®
were obtained on tapping mode using non-contact mode tips from Nanoworld (Pointprobe tip, NCHR type) -1
with spring constant of 42 N m and tip radius of ≤8 nm.
5
Additional Supporting Figures
6
Figure S1 1H NMR for (a) poly(2), (b) poly(2)60-ran-poly(1)10, (c) poly(3), and (d) poly(3)75-stat-poly(1)25. Integration analysis indicated that monomer feed ratio matched well with actual incorporated composition. 7
Figure S2 UV–vis spectra of (a) poly(2)60-ran-poly(1)10 and (b) poly(3)70-stat-poly(1)25 in chloroform solution (0.1 mg/ml).
SpinWorks 3: 2-15_block_polymer
a
d
O
O
O
f
e e
O
b
O
g
a
O
N
h
c
i
1
poly(3) b i c
2
f+h e+g
d
f
1
PPM
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1
Figure S3 H NMR peaks for 1, poly(3), and poly(3)-b-poly(1) from the top. spectrum of poly(3) overlayed with that of poly(3)-b-poly(1).
8
Figure S4 Hydrodynamic radius diagram from the solution of poly(3)100-b-poly(1)50 in CHCl3 (1 mg/ml) obtained by dynamic light scattering. Average hydrodynamic diameter is 44.8 nm.
Figure S5 UV–vis spectra of poly(3)-b-poly(1) in chloroform solution containing high and low molecular weight fractions after they were separated by SEC. The low molecular weight fraction still contained the conjugated block with slightly lower conjugation length in the second block as it showed a lower λmax peak.
9
Cyclopolymerization to synthesize conjugated polymers containing Meldrum’s acid as a precursor for ketene functionality
Jeongeun Kim, Eun-Hye Kang and Tae-Lim Choi★
Department of Chemistry, Seoul National University, Seoul, 151-747, Korea
Tae-Lim Choi [email protected] ,
1
General experimental All reactions were carried out under dry argon atmospheres using standard Schlenk-line techniques. All reagents which are commercially available were used without further purification. 5-norbornene-endo-2,3dicarboxylic anhydride was purchased from Tokyo Chemical Industry, followed by thermal isomerization to the exo-form. Solvents for monomer synthesis were also commercially obtained: tetrahydrofuran (THF) was anhydrous (≥ 99.9%) grade from Sigma-Aldrich®. For polymerization, THF was distilled from sodium and benzophenone. THF was degassed for 10 minutes before using on polymerization. Thin-layer chromatography (TLC) was carried out on MERCK TLC silica gel 60 F254 and flash column chromatography was performed using MERCK silica gel 60 (0.040~0.063 mm). 1H NMR and
13
C NMR were recorded by
Varian/Oxford As-500 (500 MHz for 1H and 125 MHz for 13C) spectrometers. UV–vis spectra were measured by Jasco Inc. UV/vis-Spectrometer V-550. Gel permeation chromatography (GPC) for polymer molecular weight analysis was carried out with Waters system (1515 pump, 2414 refractive index detector and 2489 UV detector) and Shodex GPC LF-804 column eluted with THF (GPC grade, Honeywell Burdick & Jackson). Flow rate was 1.0 mL/min and temperature of column was maintained at 35 °C. Samples in 0.5-1.0 mg/mL THF were filtered by 0.2-µm PTFE filter before injection. Gel permeation chromatography (GPC) for polymer molecular weight analysis was carried out with Waters system (515 HPLC pump and 2410 refractive refractive index detector), Acme 9000 UV/Vis detector, and Shodex GPC LF-804 column eluted CHCl3 (HPLC grade, J. T. Baker). Flow rate was 0.8 mL/min and temperature of column was maintained at 35 °C. Samples in 0.5-1.0 mg/mL CHCl3 were filtered by 0.2-µm PTFE filter before injection. High resolution mass spectroscopy (HRMS) analyses were performed by the National Center for Inter-University Research Facility. Multimode 8 and Nanoscope Ⅴ controller (Veeco Instrument) were used for AFM imaging. Dynamic Light Scattering (DLS) data were obtained by Malvern Zetasizer Nano ZS.
Experimental procedure for monomer synthesis (1-3) 2,2-dimethyl-5,5-di(prop-2-ynyl)-1,3-dioxane-4,6-dione (1) O
O O O
This monomer was prepared by the modified method from the previous literature (Jin, S.-H.; Cho, H.-N.; Choi, S.-K. J. Polym. Sci. Polym. Chem. Ed., 1993, 31, 69.). Meldrum’s acid (2,2-dimethyl-1,3-dioxane-4,6-dione) (720.7 mg, 5 mmol) and K2CO3 (99%) (1.728 g, 12.5 mmol) in acetone was prepared in RBF purged with argon. Propargyl bromide (80 wt%, in toluene) (1.23 ml, 11 mmol) was dropwised and stirred for 10 hours with reflux. The mixture was filtered and evaporated, then organic layer was extracted with ethyl acetate (75 mL * 2). The organic layer was dried with MgSO4 and concentrated to give a yellow colored liquid. It was purified by recrystallization with dichloromethane and hexane to afford compound 1 as a white crystalline. 2
(719.7 mg, 3.273 mmol, 65.5 %). 1H-NMR and
13
C-NMR data are also available in the same literature.
HRMS (CI+): calcd. for C12H13O4, 221.0814, found, 221.0815.
Dihexyl dipropargylmalonate (2) O
O
O
O
This monomer was prepared by the same method from the previous literature (Kang, E.-H.; Lee, I, S.; Choi, T.-L. J. Am. Chem. Soc. 2011, 133, 11904.). 1H-NMR,
13
C-NMR and MS analysis data are also available in
the same literature.
N-propyl-exo-norbornene-5,6-dicarboximide (3)
O N O
This monomer was prepared by slightly modified method from the previous literature (Meijer, A.; Otto, S.; Engbert, Jan B. F. N. J. Org. Chem., 1998, 63, 8989.). 1H-NMR,
13
C-NMR and MS analysis data are also
available in the same literature.
Preparation of catalyst nd
2
generation Grubbs catalyst (51.8 mg, 0.0610 mmol) and 3-chloropyridine (1 mL) were mixed in 20-ml
sized vial for 5 minutes. Cold n-pentane was poured to the vial. After storage in freezer a few hours, the 3rd generation Grubbs catalyst was filtered and washed by pentane. The green product (39.1 mg, 0.0491 mmol, 80.5%) was vacuum dried and stored in desiccator.
General polymerization procedure Random copolymerization Monomers (0.1-0.05 mmol) with the given ratios in the table 1 were weighed in a 4-ml sized screw-cap vial with septum and purged with argon. Distilled and degassed solvent (0.2 mL) was added to the vial which was placed in a cold ice bath. The solution of initiator (0.1 mL) was added at once under vigorous stirring. 3
After confirming the monomer conversion by TLC, the reaction was quenched by excess ethyl vinyl ether. The concentrated reaction mixture of poly(3)-ran-poly(1) was precipitated by methanol/isopropylalcohol 1:2 mixture and poly(2)-ran-poly(1) was precipitated by methanol. The obtained solid was dried in vacuo Reactivity ratio: To determine reactivity ratio, we used Fineman-Ross method. Mixed monomers with the ratios of [3]:[1] = 90:10, 75:25, 60:40, 45:55, and 30:70 were prepared, then the catalyst was injected at 0 °C. To obtain the ratio of incorporated monomers in early stage, the reaction was quenched after 5 seconds, and the incorporated ratios were obtained from 1H NMR analysis.
[3]/[cat]
[1]/[cat]
f1
F1
90
10
0.9
0.856
-13.6
-7.489
75
25
0.75
0.582
-6.455
-0.848
60
40
0.6
0.441
-2.853
0.402
45
55
0.45
0.277
-1.745
1.314
30
70
0.3
0.190
-0.781
1.394
Using the Fineman-Ross equation below, r1 and r3 was obtained:
Arranged Fineman-Ross equation :
f1 vs F1
vs
From the result, we obtained the values of r1 = 0.7, r3=2.5 suggesting statistical copolymer.
4
Block copolymerization Monomer for the 1st block (0.1 mmol) was weighed in a 4-ml sized screw-cap vial with septum and purged with argon. Anhydrous and degassed solvent (0.1 mL) was added to the vial. The vial was placed in a cold ice bath. The solution of initiator (0.1 mL) was added at once under vigorous stirring. After confirming the monomer conversion by TLC, the solution of 1 (0.2 mL) was added to the vial. After the solution became viscous, the reaction mixture was put in room temperature for 1 hour to assure the full conversion of 1. The reaction was quenched by excess ethyl vinyl ether and diluted by chloroform to make homogeneous polymer solution.
The
con-centrated
reaction
mixture
of
poly(3)-b-poly(1)
was
precipitated
by
methanol/Isopropylalcohol 1:2 mixture and poly(2)-b-poly(1) was precipitated by methanol. The obtained solid was dried in vacuo
Atomic Force Microscopy (AFM) The atomic force microscopy experiments were performed with a thin film prepared by spin-coating of one drop of the polymer solution (~0.01 mg/ml, CHCl3, spinning rate = 2000 rpm for 30 sec.). The polymer solution was filtered by 0.2-µm PTFE filter before spin-coating. The thin films were prepared on mica. Images ®
were obtained on tapping mode using non-contact mode tips from Nanoworld (Pointprobe tip, NCHR type) -1
with spring constant of 42 N m and tip radius of ≤8 nm.
5
Additional Supporting Figures
6
Figure S1 1H NMR for (a) poly(2), (b) poly(2)60-ran-poly(1)10, (c) poly(3), and (d) poly(3)75-stat-poly(1)25. Integration analysis indicated that monomer feed ratio matched well with actual incorporated composition. 7
Figure S2 UV–vis spectra of (a) poly(2)60-ran-poly(1)10 and (b) poly(3)70-stat-poly(1)25 in chloroform solution (0.1 mg/ml).
SpinWorks 3: 2-15_block_polymer
a
d
O
O
O
f
e e
O
b
O
g
a
O
N
h
c
i
1
poly(3) b i c
2
f+h e+g
d
f
1
PPM
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1
Figure S3 H NMR peaks for 1, poly(3), and poly(3)-b-poly(1) from the top. spectrum of poly(3) overlayed with that of poly(3)-b-poly(1).
8
Figure S4 Hydrodynamic radius diagram from the solution of poly(3)100-b-poly(1)50 in CHCl3 (1 mg/ml) obtained by dynamic light scattering. Average hydrodynamic diameter is 44.8 nm.
Figure S5 UV–vis spectra of poly(3)-b-poly(1) in chloroform solution containing high and low molecular weight fractions after they were separated by SEC. The low molecular weight fraction still contained the conjugated block with slightly lower conjugation length in the second block as it showed a lower λmax peak.
9
