Photocatalytic selective bromination of electron-rich aromatic ...
Supporting Information
Photocatalytic selective bromination of electron-rich aromatic compounds using microporous organic polymers with visible light
Run Li, Zi Jun Wang, Lei Wang, Beatriz Chiyin Ma, Saman Ghasimi, Hao Lu, Katharina Landfester and Kai. A. I. Zhang*
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany E-mail: [email protected]
S1
Investigation of Cl−and I− as halide source According to the reaction mechanism, the interaction between Br− and the cationic radical of 1,2,4trimethoxybenzene as intermediate play an essential role for the formation of bromide product. Other halides, such as chloride and iodide, should share a similar nucleophile character for the halogenation reaction. Here, additional experiments were conducted to demonstrate the general feasibility of the reaction mechanism by replacing HBr with HCl and HI, obtaining 1-chloro-2,4,5trimethoxybenzene and 1-iodo-2,4,5-trimethoxybenzene as the chlorination and iodination products.
X= Cl and I The chlorination of 1,2,4-trimethoxybenzene (TMB) was carried out in a similar procedure. Typically, photocatalyst (MOPs, 10 mg) and TMB (5.97 ul, 0.04 mmol) were dissolved in 10 ml acetonitrile. 37 % aqueous solution of HCl (32.85 ul, 0.4 mmol) was added and the mixture was saturated with O2 by bubbling O2 for 5 min, and then irradiated with a blue LED lamp (460 nm, 1.2 W/cm 2) at room temperature for overnight. After being extracted with brine and hexane, the crude product was purified via column chromatography. Yield: 70% Rf (hexane/ethyl acetate 14/1): 0.15 1
H NMR (CDCl3, 300 MHz): δ 6.82 (s, 1H), 6.50 (s, 1H), 3.81 (s, 3H), 3.80 (s, 3H), 3.76 (s, 3H);
13
C NMR (CDCl3, 300 MHz): δ 149.2, 148.4, 143.5, 113.7, 113.0, 99.1, 57.2, 56.6, 56.3.
The iodination of 1,2,4-trimethoxybenzene (TMB) was carried out in a similar procedure. Typically, photocatalyst (MOPs, 10 mg) and TMB (5.97 ul, 0.04 mmol) were dissolved in 10 ml acetonitrile. 57 % aqueous solution of HI (7.92 ul, 0.06 mmol) was added and the mixture was saturated with O2 by bubbling O2 for 5 min, and then irradiated with a blue LED lamp (460 nm, 1.2 W/cm 2) at room temperature for overnight. After being extracted with brine and hexane, the crude product was purified via column chromatography. Yield: 51% Rf (hexane/ethyl acetate 5/1): 0.34 1
H NMR (CDCl3, 300 MHz): δ 7.13 (s, 1H), 6.43 (s, 1H), 3.81 (s, 3H), 3.78 (s, 3H), 3.76 (s, 3H);
13
C NMR (CDCl3, 300 MHz): δ 153.0, 150.2, 144.2, 121.9, 97.8, 73.0, 57.3, 56.7, 56.2.
S2
Figure S1. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-0b.
S3
Figure S2. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-0.
S4
Figure S3. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-1b.
S5
Figure S4. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-1.
S6
Figure S5. Solid State 13C/MAS NMR with an idealized structure of MOP-0.
Figure S6. Solid State 13C/MAS NMR with an idealized structure of MOP-1.
S7
Figure S7. UV/Vis absorption spectra of BT-Ph2 in DMF solutions. Concentration: ~ 20 mg/L.
S8
Figure S8. Cyclic voltammetry of MOP-0, (a) reduction cycle and (b) oxidation cycle.
S9
(a) 0
I/A
-10
-20
-30
-40 -1.5
-1.0
-0.5
0.0
E/V
Figure S9. Cyclic voltammetry of MOP-1, (a) reduction cycle and (b) oxidation cycle.
S10
Figure S10. UPS spectrum of MOP-0 (black curve). The dashed red lines mark the baseline and the tangents of the curve.
Figure S11. UPS spectrum of MOP-1 (black curve). The dashed red lines mark the baseline and the tangents of the curve.
S11
Figure S12. EPR spectra of MOP-0 taken in dark and under light irradiation.
Figure S13. EPR spectra of MOP-1 taken in dark and under light irradiation.
S12
Figure S14. Thermogravimetric analysis of the MOPs.
S13
Figure S15. (a) UV-Vis absorption spectra of pure water and reaction system with or without catalyst after adding DPD and POD for H2O2 determination. (b) Standard curve of H2O2 concentration based on its absorption maximum at 551 nm. This method is based on the POD-catalyzed oxidation reaction of DPD by H2O2, which gives the radical cation DPD•+. The radical cation can be easily determined by its two typical absorption peaks at ca. 510 and 551 nm.
S14
Figure S16. Monitoring experiment of the photocatalytic bromination reaction of TMB.
Figure S17. Repeating experiment of the photocatalytic bromination of TMB using MOP-1 as photocatalyst.
S15
Figure S18. FTIR spectra of MOP-1 before (black) and after (red) 5 repeating cycles of the photocatalytic bromination of TMB.
S16
Figure S19. SEM and TEM images of MOP-1 after 5 repeating cycles of the photocatalytic bromination of TMB.
S17
Figure S20. Suggested mechanism for the formation of benzaldehyde instead of p-bromotoluene with toluene being as reactive substrate due to the high oxidation potential of toluene (1.98 V vs. SCE). The VB of MOP-1 lay at ca. 1.75 V vs. SCE, which was not sufficient to be able to oxidize the phenyl ring of toluene. The formation of the cationic radical of toluene could not occur. The desired brominated product could therefore not be obtained.
S18
1
H-NMR and 13C-NMR spectra of monomers
Figure S21. 1H and 13C NMR spectra of BT-Ph2.
S19
1
H-NMR and 13C-NMR spectra of products obtained by photocatalysis bromination with MOP-1 as photocatalyst
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Photocatalytic selective bromination of electron-rich aromatic compounds using microporous organic polymers with visible light
Run Li, Zi Jun Wang, Lei Wang, Beatriz Chiyin Ma, Saman Ghasimi, Hao Lu, Katharina Landfester and Kai. A. I. Zhang*
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany E-mail: [email protected]
S1
Investigation of Cl−and I− as halide source According to the reaction mechanism, the interaction between Br− and the cationic radical of 1,2,4trimethoxybenzene as intermediate play an essential role for the formation of bromide product. Other halides, such as chloride and iodide, should share a similar nucleophile character for the halogenation reaction. Here, additional experiments were conducted to demonstrate the general feasibility of the reaction mechanism by replacing HBr with HCl and HI, obtaining 1-chloro-2,4,5trimethoxybenzene and 1-iodo-2,4,5-trimethoxybenzene as the chlorination and iodination products.
X= Cl and I The chlorination of 1,2,4-trimethoxybenzene (TMB) was carried out in a similar procedure. Typically, photocatalyst (MOPs, 10 mg) and TMB (5.97 ul, 0.04 mmol) were dissolved in 10 ml acetonitrile. 37 % aqueous solution of HCl (32.85 ul, 0.4 mmol) was added and the mixture was saturated with O2 by bubbling O2 for 5 min, and then irradiated with a blue LED lamp (460 nm, 1.2 W/cm 2) at room temperature for overnight. After being extracted with brine and hexane, the crude product was purified via column chromatography. Yield: 70% Rf (hexane/ethyl acetate 14/1): 0.15 1
H NMR (CDCl3, 300 MHz): δ 6.82 (s, 1H), 6.50 (s, 1H), 3.81 (s, 3H), 3.80 (s, 3H), 3.76 (s, 3H);
13
C NMR (CDCl3, 300 MHz): δ 149.2, 148.4, 143.5, 113.7, 113.0, 99.1, 57.2, 56.6, 56.3.
The iodination of 1,2,4-trimethoxybenzene (TMB) was carried out in a similar procedure. Typically, photocatalyst (MOPs, 10 mg) and TMB (5.97 ul, 0.04 mmol) were dissolved in 10 ml acetonitrile. 57 % aqueous solution of HI (7.92 ul, 0.06 mmol) was added and the mixture was saturated with O2 by bubbling O2 for 5 min, and then irradiated with a blue LED lamp (460 nm, 1.2 W/cm 2) at room temperature for overnight. After being extracted with brine and hexane, the crude product was purified via column chromatography. Yield: 51% Rf (hexane/ethyl acetate 5/1): 0.34 1
H NMR (CDCl3, 300 MHz): δ 7.13 (s, 1H), 6.43 (s, 1H), 3.81 (s, 3H), 3.78 (s, 3H), 3.76 (s, 3H);
13
C NMR (CDCl3, 300 MHz): δ 153.0, 150.2, 144.2, 121.9, 97.8, 73.0, 57.3, 56.7, 56.2.
S2
Figure S1. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-0b.
S3
Figure S2. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-0.
S4
Figure S3. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-1b.
S5
Figure S4. (a) Nitrogen sorption and desorption isotherms, and (b) pore size distributions of MOP-1.
S6
Figure S5. Solid State 13C/MAS NMR with an idealized structure of MOP-0.
Figure S6. Solid State 13C/MAS NMR with an idealized structure of MOP-1.
S7
Figure S7. UV/Vis absorption spectra of BT-Ph2 in DMF solutions. Concentration: ~ 20 mg/L.
S8
Figure S8. Cyclic voltammetry of MOP-0, (a) reduction cycle and (b) oxidation cycle.
S9
(a) 0
I/A
-10
-20
-30
-40 -1.5
-1.0
-0.5
0.0
E/V
Figure S9. Cyclic voltammetry of MOP-1, (a) reduction cycle and (b) oxidation cycle.
S10
Figure S10. UPS spectrum of MOP-0 (black curve). The dashed red lines mark the baseline and the tangents of the curve.
Figure S11. UPS spectrum of MOP-1 (black curve). The dashed red lines mark the baseline and the tangents of the curve.
S11
Figure S12. EPR spectra of MOP-0 taken in dark and under light irradiation.
Figure S13. EPR spectra of MOP-1 taken in dark and under light irradiation.
S12
Figure S14. Thermogravimetric analysis of the MOPs.
S13
Figure S15. (a) UV-Vis absorption spectra of pure water and reaction system with or without catalyst after adding DPD and POD for H2O2 determination. (b) Standard curve of H2O2 concentration based on its absorption maximum at 551 nm. This method is based on the POD-catalyzed oxidation reaction of DPD by H2O2, which gives the radical cation DPD•+. The radical cation can be easily determined by its two typical absorption peaks at ca. 510 and 551 nm.
S14
Figure S16. Monitoring experiment of the photocatalytic bromination reaction of TMB.
Figure S17. Repeating experiment of the photocatalytic bromination of TMB using MOP-1 as photocatalyst.
S15
Figure S18. FTIR spectra of MOP-1 before (black) and after (red) 5 repeating cycles of the photocatalytic bromination of TMB.
S16
Figure S19. SEM and TEM images of MOP-1 after 5 repeating cycles of the photocatalytic bromination of TMB.
S17
Figure S20. Suggested mechanism for the formation of benzaldehyde instead of p-bromotoluene with toluene being as reactive substrate due to the high oxidation potential of toluene (1.98 V vs. SCE). The VB of MOP-1 lay at ca. 1.75 V vs. SCE, which was not sufficient to be able to oxidize the phenyl ring of toluene. The formation of the cationic radical of toluene could not occur. The desired brominated product could therefore not be obtained.
S18
1
H-NMR and 13C-NMR spectra of monomers
Figure S21. 1H and 13C NMR spectra of BT-Ph2.
S19
1
H-NMR and 13C-NMR spectra of products obtained by photocatalysis bromination with MOP-1 as photocatalyst
S20
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