Supple. KBr. C N) cm (s, p-phenenylene

Transcription

1 Supple ementary Information Supplementary Figures Supplementary Figure S1. FTIR spectra of azo-cops. The spectra were recorded as KBr pellets (s, free N H), (s, hydrogen bonded N H), 1610 (s, C=C aromatic), 1447 and 1403 (s, N=N), 1520 and 1340 (s, N O) ), 1280 (s, C N) cm 1. 55, 56 TNPM: Tetrakis (4- nitrophenyl)methane, TAPM: 4,4',4'',4'''-methane-tetrayltetraaniline, PDA: p-phenenylene diamine and BD: Benzidine S1

2 Supplementary Figure S2. CP/ /MAS 13 C NMR spectraa of azo-cops and assignments of each chemical shift. δ = 150.2, 144.7, , 123.4, 54.9 ppm. 5 57, 19 TNPM: Tetrakis (4- nitrophenyl)methane, TAPM: 4,4',4'',4'''-methane-tetrayltetraaniline. *Terminal C NH 2, 115 ppm. S2

3 Supplementary Figure S3. UV-visible spectra of azo-cops were collected before and after UV (365 nm) irradiation by using hand-held UV-lamp for different time intervals. Switching (trans cis) of azobenzene units within azo-cop-2 is evidenced clearly by the decrease in the trans-azobenzene absorbtion band located at 360 nm and also by the formation of a broad cis- azobenzene band located at 440 nm. S3

4 Supplementary Figure S4. Diffuse reflectance spectraa of azo-cops obtained from solid-state UV-visible spectroscopy in orderr to evaluatee energy band gap, E g (ev). S4

5 Supplementary Figure S5. Powder X-ray diffraction patterns of azo-cops indicate clearly the formation of amorphous porous polymers. S5

6 Supplementary Figure S6. Small angle X-ray scatteringg (SAXS) of azo-cops. Azo-COP-1 indicate the and azo-cop-2 show low angle reflection at [151] and [146], respectively. These results presence of mesoporous networks formed in azo-cop-1 and -2. S6

7 Supplementary Figure S7. Thermogravimetric analysis (TGA) of azo-cops under air and N 2 atmosphere up to 8000 C at a rate of 10 C min 1. S7

8 Supplementary Figure S8. Water stability of azo-cops mg of azo-cops were dispersedd in distilledd H 2 O (15 ml) and kept at 100 C for a week. Afterwards, the solids were removed by filtration and dried at 100 C under vacuum for 24 h. Their respective (a) surface areas (m 2 g 1 ) from N 2 adsorption desorptionn at 77 K and (b) CO 2 adsorptions (mg g 1 ) at 273 K and 1 bar were measured. Azo-COP-1, azo-cop-2 and azo-cop-3 showed no significant loss of surface areas or CO 2 capacities, thus proving their robustt nature. S8

9 Supplem mentary Figu ure S9. Fielld Emission Scanning Ellectron Micrroscopy (FE-SEM) imagges of azo-cop Ps. S9

10 Supplem mentary Figu ure S10. Traansmission Electron E Miccroscopy (TE EM) images of azo-cop Ps. S10

11 Supplementary Figure S11. Differential scanning calorimetry (DSC) analysis of azo-cops. Samples were first heated to 280 C to remove any thermal history. Thermal transitions were measured at a second heating scan on a NETZSCH DSC 204 F1 instrument at a scan rate of 10 C min 1 in N 2 flow in the range of 60 to +280 C. The glass transition temperature (T g ) was observed at C for all azo-cops. S11

12 Supplementary Figure S12. BET plot (P/Po = ) of azo-cops from Ar isotherms at 87 K. S12

13 Supplementary Figure S13. Nitrogen adsorption-desorption isotherms at 77 K of azo-cop-1, - 2 and -3. Filled and empty symbols represent adsorptionn and desorption, respectively. Inset: pore volume versus pore size. S13

14 Supplementary Figure S14. BET plot (P/Po = ) of azo-cops from N 2 isotherms at 77 K. S14

15 Supplementary Figure S15. BET linear plot and surface area of azo-cops calculated from CO 2 isotherms at 273 K. S15

16 263 K CO 2 adsorption / mmol g CO 2 q sat b A azo-cop azo-cop azo-cop azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted Pressure / bar N 2 adsorption / mmol g azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted Pressure / bar 263 K N 2 q sat b A azo-cop azo-cop azo-cop Supplementary Figure S16. Langmuir model fits for CO 2 and N 2 adsorption of azo COPs 1, 2, 3 at 263 K. S16

17 K CO 2 adsorption / mmol g CO 2 q sat b A azo-cop azo-cop azo-cop azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted Pressure / bar N 2 adsorption / mmol g azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted N 2 q sat b A azo-cop azo-cop azo-cop Pressure / bar 273 K Supplementary Figure S17. Langmuir model fits for CO 2 and N 2 adsorption of azo COPs 1, 2, 3 at 273 K. S17

18 CO 2 adsorption / mmol g K CO 2 q sat b A azo-cop azo-cop azo-cop azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted Pressure / bar N 2 adsorption / mmol g azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted N 2 q sat b A azo-cop azo-cop azo-cop K Pressure / bar Supplementary Figure S18. Langmuir model fits for CO 2 and N 2 adsorption of azo COPs 1, 2, 3 at 298 K. S18

19 323 K CO 2 adsorption / mmol g CO 2 q sat b A azo-cop azo-cop azo-cop azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted Pressure / bar N 2 adsorption / mmol g azo-cop-1 azo-cop-1-fitted azo-cop-2 azo-cop-2-fitted azo-cop-3 azo-cop-3-fitted Pressure / bar 323 K N 2 q sat b A azo-cop azo-cop azo-cop Supplementary Figure S19. Langmuir model fits for CO 2 and N 2 adsorption of azo COPs 1, 2, 3 at 323 K. S19

20 K K Selectivity 40 Selectivity azo-cop-1 azo-cop-2 azo-cop-3 50 azo-cop-1 azo-cop-2 azo-cop Pressure / bar Pressure / bar K K Selectivity Selectivity azo-cop-1 azo-cop-2 azo-cop azo-cop-1 azo-cop-2 azo-cop Pressure / bar Pressure / bar Supplementary Figure S20. IAST selectivity of azo COPs 1, 2, 3 at 263, 273, 298 and 323 K with respect to pressure (0 to 1.0 bar) for CO 2 :N 2 (15:85) gas mixture. S20

21 Supplementary Figure S21. CO 2 /N 2 selectivities for azo-cop-1 calculated using the Henry`s Law constants in the linear low pressure (<0.1 bar) range. CO 2 /N 2 = (263 K), (273 K), (298 K), (323 K). S21

22 Supplementary Figure S22. CO 2 /N 2 selectivities for azo-cop-2 calculated using the Henry`s Law constants in the linear low pressure (<0.1 bar) range. CO 2 /N 2 = (263 K), (273 K), (298 K), (323 K). S22

23 Supplementary Figure S23. CO 2 /N 2 selectivities for azo-cop-3 calculated using the Henry`s Law constants in the linear low pressure (<0.1 bar) range. CO 2 /N 2 = (263 K), (273 K), (298 K), (323 K). S23

24 Supplementary Figure S24. Interaction energy distribution at different temperatures and pressures. S24

25 Supplementary Figure S25. Schematic diagram for thee adsorption entropy for CO 2 and N 2 that is responsible for the temperaturee dependence of the selectivity increase. S25

26 Energy distribution CO2 N2 Probability Energy / kj mol -1 Supplementary Figure S26. The gas-framework interaction energy distribution for CO 2 (red) and N 2 (blue) at 263 K and 1.0 bar. S26

27 Spatial distribution CO2 N2 Probability Distance / Å Supplementary Figure S27. The distance distribution between the center of mass of the gas molecule and the azo group. S27

28 Supplementary Tables Supplementary Table S1. Surface area and average pore size of azo-cops. All the measurements are carried out using 1 g of each azo-cop. Samples BET Surface area / m 2 g -1 Langmuir Micropore (NLDFT) Pore size / nm Pore volume / cm 3 g -1 azo-cop-1 azo-cop-2 azo-cop-3 Argon Nitrogen Argon Nitrogen Argon Nitrogen The Pore Size Distribution of azo-cops was calculated from the Ar and N 2 adsorption isotherms by the Non-Local Density Functional Theory (NLDFT) method using a cylindrical pore model. Pore volume of azo-cops was calculated at P/Po = S28

29 Supplementary Table S2. Comparison of CO 2 and N 2 capture and CO 2 /N 2 selectivity of selected porous polymers reported in the literature and present work. CO 2 adsorption at 1 bar N 2 adsorption at 1 bar Selectivity Ref. mg g -1 mg g -1 CO 2 /N K 273 K 298 K 323 K 263 K 273 K 298 K 323 K Method 263 K 273 K 298 K 323 K CTFs IAST PECONF Henry BILP Henry OCF b a - Henry a - 58 azo-cop- 1 azo-cop- 2 azo-cop Henry Present work IAST Henry Present work IAST Henry Present work IAST a Porous polymers reported in this table are selected based their performances, see Ref 2 for a more comprehensive data set. b Measured at 295 K. Henry s selectivity measured below 0.1 bar. IAST measured from simulated CO 2 /N 2 (0.15/0.85) mixture S29

30 Supplementary Table S3. Decomposition of the total binding energy into the SCF and correlation energy components for the CO 2 /trans-azobenzene and N 2 /trans-azobenzene model complexes. N 2 /azo and N 2 /ben stand for the binding configuration of N 2 either on top of azogroup or benzene ring, respectively. Note that the adsorption energy become negative only after including correlation effects (dispersion interactions). CO 2 N 2 /azo N 2 /ben SCF Energy RIMP2 Correlation Energy Total adsorption energy S30

31 Supplementary Table S4. The SCF energy decomposition analysis for CO 2 /trans-azobenzene and N 2 /trans-azobenzene. FRZ, POL and SCF-CT denote frozen density energy, polarization energy of the relaxation of charge density onto its own molecular orbitals, and charge transfer energy by mixing the molecular orbitals on both sides, respectively. Energy Decomposition CO 2 N 2 /azo % difference (N 2 /azo CO 2 ) N 2,ben % difference (N 2,ben CO 2 ) FRZ HF POL SCF-CT Total S31

32 Supplementary Table S5. The distance and energy distributions for the CO 2 and N 2 adsorption configurations using grand canonical Monte Carlo (GCMC) simulations at different temperatures. Due to a difficulty in structure prediction for the amorphous polymers, CPL-4 is used as a model crystalline system that contains azo and aromatic rings. Distance (Å) Binding Site Azo (-N=N-) Benzene 298 K 1.0 bar 263 K 1.0 bar Gas CO 2 N 2 CO 2 N 2 Mean STD Mean STD S32

33 Supplementary Methods 1. Materials All reagents and solvents were purchased from commercial sources and were used without further purification, unless indicated otherwise. Tetrakis(4-nitrophenyl)methane 43 and 4,4',4'',4'''- Methanetetrayltetraaniline 43 were prepared following procedures reported in the literature. All reactions were performed under N 2 atmosphere and in dry solvents unless otherwise noted. 2. Synthesis of azo-linked Covalent Organic Polymers (azo-cops-1, -2, -3) Note: Structural formulae of azo-cops are provided solely for the clear understanding of the reaction. The final structures of azo-cops-1, -2, -3 drawn in the reaction schemes of the respective synthesis may not resemble the actual experimental product. The azo-cops obtained in this study, are amorphous and do not have ordered structures (as confirmed from X-ray diffraction patterns, Supplementary Figure S5) Synthesis of azo-cop-1 Azo-COP-1: Tetrakis(4-nitrophenyl)methane (0.197 g, 0.39 mmol) and 4,4',4'',4'''-methanetetrayltetraaniline (0.15 g, 0.39 mmol) were dissolved in DMF (25 ml) in a three-necked round bottom flask equipped with a condenser, thermocouple and magnetic stirrer. KOH (0.22 g, 3.94 S33

34 mmol) was added to this solution while stirring. The temperature of the reaction mixture was increased slowly up to 150 C with vigorous stirring under N 2 atmosphere and stirred at this temperature for 24 h. The colour of the solution was changed from light yellow to orange, which was followed by the formation of orange precipitates. The reaction mixture was cooled to room temperature, added to 150 ml of distilled H 2 O and stirred for 1 h. Orange precipitate was filtered off and washed with warm distilled H 2 O (x4), Me 2 CO (x3) and THF (x3). Subsequently, orange precipitates were dried at 110 C under vacuum for 4 h to yield azo-cop-1 (0.2 g) in 57 % yield. Elemental Analysis (CHNO): %C (80.63), 3.86 %H (4.33), %N (15.04), 4.91 %O. CP/MAS 13 C NMR: δ = 150.2, 144.7, 129.5, 123.4, 54.9 ppm. FTIR: 3200 (s, hydrogen bonded N H), 1610 (s, C=C aromatic), 1447 and 1403 (s, N=N), 1520 and 1340 (s, N O), 1280 (s, C N) cm Synthesis of azo-cop-2 Azo-COP-2: Tetrakis(4-nitrophenyl)methane (0.2 g, 0.4 mmol) and p-phenylenediamine (0.086 g, 0.4 mmol) were dissolved in DMF (25 ml) in a three-necked round bottom flask equipped S34

35 with a condenser, thermocouple and a magnetic stirrer. KOH (0.22 g, 3.94 mmol) was added to this solution while stirring. The temperature of the reaction mixture was increased slowly up to 150 C with vigorous stirring under N 2 atmosphere and stirred at this temperature for 24 h. The colour of the solution was changed from light yellow to orange, which was followed by the formation of orange precipitates. The reaction mixture was cooled to room temperature, added to 150 ml of distilled H 2 O and stirred for 1 h. Orange precipitate was filtered off and washed with warm distilled H 2 O (x4), Me 2 CO (x3) and THF (x3). Subsequently, orange precipitates were dried at 110 C under vacuum for 4 h to yield azo-cop-1 (0.15 g) in 53 % yield. Elemental Analysis (CHNO): %C (76.54), 3.78 %H (4.17), %N (19.30), 5.75 %O. CP/MAS 13 C NMR: δ = 150.2, 144.7, 129.5, 123.4, 54.9 ppm. FTIR: 3200 (s, hydrogen bonded N H), 1610 (s, C=C aromatic), 1447 and 1403 (s, N=N), 1520 and 1340 (s, N O), 1280 (s, C N) cm Synthesis of azo-cop-3 Azo-COP-3: Tetrakis(4-nitrophenyl)methane (0.2 g, 0.4 mmol) and benzidine (0.147 g, 0.4 mmol) were dissolved DMF (25 ml) in a three-necked round bottom flask equipped with a S35

36 condenser, thermocouple and a magnetic stirrer. KOH (0.22 g, 3.94 mmol) was added to this solution while stirring. The temperature of the reaction mixture was increased slowly up to 150 C with vigorous stirring under N 2 atmosphere and stirred at this temperature for 24 h. The colour of the solution was changed from light yellow to orange, which was followed by the formation of orange precipitates. The reaction mixture was cooled to room temperature, added to 150 ml distilled H 2 O and stirred for 1 h. Orange precipitate was filtered off and washed with warm distilled H 2 O (x4), Me 2 CO (x3) and THF (x3). Subsequently, orange precipitates were dried at 110 C under vacuum for 4 h to yield azo-cop-1 (0.14 g) in 40 % yield. Elemental Analysis (CHNO): %C (80.42), 4.31 %H (4.38), %N (15.21), 3.89 %O. CP/MAS 13 C NMR: δ = 150.2, 144.7, 129.5, 123.4, 54.9 ppm. FTIR: 3200 (s, hydrogen bonded N H), 1610 (s, C=C aromatic), 1447 and 1403 (s, N=N), 1520 and 1340 (s, N O), 1280 (s, C N) cm Isosteric heats of adsorption Isosteric heats of adsorption were calculated from the adsorption data using Clausius-Clapeyron equation, Δ = R ln P H o ad 1 ( ) T θ (1) Where, R is the universal gas constant, θ is the fraction of the adsorbed sites at a pressure P and temperature T. 4. Ideal Adsorbed Solution Theory (IAST) 59,60 The calculations for IAST can be derived from the fitting adsorption isotherms with a proper Langmuir model (Myers and Prausnitz, 1965) 60. The absolute component loadings were fitted with either a single site Langmuir model or a dual site Langmuir model. Single site Langmuir S36

37 model was applied when there were no noticeable isotherm inflections. These models were fitted purely on the basis of giving the best fit with adjusted R 2 values exceeding The OriginPro v8.5 was used to solve and calculate the following equations. The single site Langmuir model can be defined as, q = q sat bp 1 + bp (2) The dual site Langmuir model can be defined as, q = q A + q B = q sat,ab A p 1 + b A p + q sat,bb B p 1 + b B p (3) where, q is molar loading of adsorbate; q sat is saturation loading; b is parameter in the pure component Langmuir adsorption isotherm, A and B is referring to two different sites. The IAST selectivities for the CO 2 :N 2 (15:85) gas mixtures were calculated using following equation, S = q 1 /q 2 p 1 /p 2 (4) Where, S is the selectivity factor, q 1 and q 2 represent the quantity adsorbed of component 1 and 2, and p 1 and p 2 represents the partial pressure of component 1 and 2. S37

38 Supplementary References: 55. Saiz, L. M., Oyanguren, P. A. & Galante, M. J. Polyurethane-epoxy based azopolymers: influence of chemical structure over photoinduced birefringence. React. Funct. Polym. 72, (2012). 56. García, T. et al. Synthesis and characterization of novel amphiphilic azo-polymers bearing well-defined oligo(ethylene glycol) spacers. Desig. Monom. Polym. 15, (2012). 57. Xie, S. A., Natansohn, A. & Rochon, P. Compatibility studies of some azo polymer blends. Macromolecules 27, (1994). 58. Jin, Y. H. et al. Microwave-assisted syntheses of highly CO 2 -selective organic cage frameworks (OCFs). Chem. Sci. 3, (2012). 59. Lu, W. et al., Polyamine-Tethered Porous Polymer Networks for Carbon Dioxide Capture from Flue Gas. Angew. Chem. Int. Ed. 51, (2012). 60. Myers, A. L. & Prausnitz, J. M., Thermodynamics of mixed-gas adsorption. A.I.Ch.E. J. 11, (1965). S38