Supporting Information

Structural Effects in Visible-Light-Responsive Metal Organic Frameworks Incorporating ortho-fluoroazobenzenes Sonia Castellanos,* [a] Alexis Goulet-Hanssens, [b] Fangli Zhao, [b] Alla Dikhtiarenko, [a] Alexey Pustovarenko, [a] Stefan Hecht, [b] Jorge Gascon, [a] Freek Kapteijn, [a] and David BlØger* [b] chem_201503503_sm_miscellaneous_information.pdf

Supporting Information Structural effects in visible-light-responsive metal-organic frameworks incorporating ortho-fluoroazobenzenes Sonia Castellanos, a, * Alexis Goulet-Hanssens, b Fangli Zhao, b Alla Dikhtiarenko, a Alexey Pustovarenko, a Stefan Hecht, b Jorge Gascon, a Freek Kapteijn, a and David Bléger b, * a Catalysis Engineering-Chemical Engineering Department, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands. E-mail: s.castellanosortega@tudelft.nl b Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany. E-mail: david.bleger@chemie.hu-berlin.de Table of Contents 1. Synthetic and Analytical General Methods S2 2. Synthetic Procedures S2 3. Characterization of the F-azo-MOFs S4 4. Photoisomerization studies S9 5. Gas uptake experiments S15 1 of 18

1. Synthetic and Analytical General Methods The commercial starting materials were used as supplied. The solvents were either used as received or dried employing an Innovative Technologies solvent purification system. Silica gel (Merck 60, particle size 0.040 0.063 mm) was used for column chromatography. NMR spectra were recorded on a Bruker 300 MHz (75 MHz for 13 C, 282 MHz for 19 F) spectrometer using residual protonated solvent signals as internal standards for 1 H- and 13 C-spectra ( 1 H-NMR: δ (CDCl 3) = 7.26 ppm, δ (DMSO-d 6) = 2.50 ppm and 13 C-NMR: δ (CDCl 3) = 77.16 ppm, δ (DMSO-d 6) = 39.52 ppm) or CFCl 3 as external standards for 19 F-spectra. Multiplicities are abbreviated as follows: singlet (s), doublet (d), triplet (t), quadruplet (q), quintet (quint), multiplet (m), and broad (br). Ultraperformance liquid chromatography coupled to mass spectrometry detection (UPLC-MS) was performed with a Waters Alliance system (gradient mixtures of acetonitrile/water) equipped with Acquity UPLC columns. The Waters system consisted of a Waters Separations Module 2695, a Waters Diode Array detector 996, a LCT Premier XE mass spectrometer, and a Waters Mass Detector ZQ 2000. DRIFT spectra were recorded in a Bruker model IFS66 spectrometer, equipped with a high temperature cell with CaF 2. The MOF samples were pretreated in a He flow (10 ml/min) at 323 K until removal of adsorbed water and the flow was maintained during the measurements. Diffuse reflectance (BaSO 4 as a white standard) and absorption UV-Vis spectra were collected using a Perkin Elmer Lambda 900 spectrophotometer equipped with an integrating sphere ( Labsphere ). CO 2 isotherms were measured in a Micromeritics Tristar II 3020 equipment at 273 K in a range of partial pressures from 0.0005 to 0.035. Before every measurement the samples were activated at 403 K under vacuum (0.05 atm) for 16 h. 2 of 18

2. Synthetic Procedures Scheme S1. Synthetic route to ligand L. MeL: To a solution of 2,6-difluoroaniline (11.1 g, 86 mmol) in DCM (220 ml) was added a solution of Oxone (52.8 g, 172 mmol) in H 2O (275 ml), the mixture was stirred overnight at room temperature. The two phases were separated and the organic phase was concentrated under vacuum to get the nitroso compound as a brown solid, which was used without further purification. The nitroso derivative was dissolved in AcOH (240 ml), then dimethyl 2-aminoterephthalate (18.0 g, 86 mmol) was added, and the solution was stirred for 5 days at 40 C. The resulting solution was extracted with DCM, the organic phases were dried over MgSO 4, filtered and concentrated under vacuum. The residue was purified by column chromatography (DCM/PE : 1/5 to 1/2) to give MeL as a dark orange solid (9.3 g, 32%). 1 H NMR (300 MHz, CDCl 3) (E-isomer) δ ppm 8.27 (d, J = 1.6 Hz, 1 H), 8.18 (dd, J = 8.0, 1.6 Hz, 1 H), 7.84 (d, J = 8.0 Hz, 1 H), 7.43 7.33 (m, 1 H), 7.06 (t, J = 9.4 Hz, 2 H), 3.96 (s, 3 H), 3.92 (s, 3 H). 13 C NMR (75 MHz, CDCl 3) (E-isomer) δ ppm 167.38, 165.65, 157.87, 151.80, 133.29, 133.17, 131.73, 131.32, 129.62, 120.01, 112.84, 112.56, 52.74, 52.64. 19 F NMR (282 MHz, CDCl 3) (Eisomer) δ ppm -119.8 (s). HRMS-ESI: m/z = 335.0825 (calcd for [M + H] +, 335.0843). L: To a solution of MeL (5.5 g, 16 mmol) in THF/H 2O: 2/1 (150 ml) was added LiOH (1.2 g, 49 mmol), and the reaction mixture was stirred for 1.5 h at room temperature. The THF was then removed under vacuum and the aqueous phase acidified to ph 3 with HCl (1 M). The precipitate was filtered and dried to obtain the product (5.7 g, 85%) as an orange solid. 1 H NMR (300 MHz, DMSO-d 6) (Eisomer) δ ppm 13.56 (br s, 2 H), 8.17 (dd, J = 8.0, 1.3 Hz, 1 H), 8.03 (d, J = 1.5 Hz, 1 H), 7.91 (d, J = 8.0 Hz, 1H), 7.67 7.61 (m, 1 H), 7.37 (t, J = 9.5 Hz, 2 H). 13 C NMR (75 MHz, D MSO-d 6) (E-isomer) δ ppm 168.08, 166.46, 157.25, 153.83, 150.95, 135.56, 133.96, 133.48, 132.21, 129.93, 118.45, 19 113.76, 113.51. F NMR (282 MHz, DMSO-d 6) (E-isomer) δ ppm -120.46 (m). HRMS-ESI: 3 of 18

m/z = 307.0194 (calcd for [M + H] +, 307.0167). Elemental analysis: C, 54.57; H, 2.72; N, 9.01 (calcd: C, 54.51; H, 3.52; N, 8.56). L decomposes at 265 C (no melting point). F-azo-UiO-66(Zr): ZrCl 4 (82 mg, 0.35 mmol) was introduced into a Teflon inset containing DMF (3.5 ml) and HCl (0.7 ml) and dissolved by sonicating for 10 min. DMF (7 ml) and L (150 mg, 0.49 mmol) were then added to the solution. The inset was placed in a stainless steel autoclave and the system heated up in the oven at 80 C for 8 h. Once cooled down to RT, the orange powder was filtered and washed with abundant DMF until the washing solvent remained colourless. The resulting MOF (109 mg, 54 %) was then washed with MeOH and dried at low pressure. F-azo-MIL-53(Al): To a solution of AlCl 3.6H 2O (118 mg, 0.49 mmol) in DMF (8.5 ml) prepared in a Teflon inset, L (150 mg, 0.49 mmol) and DMF (1.5 ml) were added. The Teflon inset was placed in a stainless steel autoclave and the systems heated up to 120 C for 8 h. Once cooled down to RT, the orange powder was filtered, washed with abundant DMF. Residual linker molecules in the pores were removed by heating the MOF in the autoclave with DMF (8 ml) at 120 C for 8 h. Once cooled down to RT, the powder was filtered, and DMF was exchanged with MeOH (8 ml), in the Teflon inset at 70 C for 5 h. Activation of the resulting MOF (100 mg. 60 %) was performed by filtering and drying at 80 C overnight. 3. Characterization of the F-azo-MOFs Powder X-ray diffraction studies and refinement procedures The powder X-ray diffraction measurements were performed on a Bruker D8-Advance diffractometer operated in Bragg-Brentano geometry, equipped with a Co-Kα source ( = 1.78897 Å). All diffraction data were collected over an angle range from 5 to 80 with a step width of 0.02 and scan speed of 0.2 /s. Indexation, Le Bail extraction and unit cell parameter refinement of F-azo-UiO-66(Zr) and F- azo-mil-53(al) have been performed with EXPO2014. [1] In the first refinement step, zero offset, the scale factor, six background terms and profile parameters as a pseudo-voigt function were refined. Additionally, for F-azo-MIL-53(Al) MOF, the rigid body/torsion angle simulated annealing was performed to determine the orientation and conformation of F-azo-groups within the network. The three internal degrees of freedom for F-azo-group were set on torsional angles, while all covalent bond lengths were constrained to their theoretically relevant values. 4 of 18

Figure S1. The Le Bail fitting plot for F-azo-UiO-66(Zr) presented with corresponding R-factors. The experimental data are presented as black solid line, the calculated data by red crosses and difference as blue solid line. The Bragg positions of the peaks are represented as green sticks. Figure S2. PXRD patterns of UiO-66(Zr) (black) and of F-azo-UiO-66(Zr) (orange). 5 of 18

Figure S3. The refinement plot for F-azo-MIL-53(Al) MOF presented with corresponding R-factors. The experimental data are presented as black solid line, the calculated data by red crosses and difference as blue solid line. The Bragg positions of the peaks are represented as green sticks. Figure S4. SEM pictures of F-azo-MIL-53(Al) (left) and of F-azo-UiO-66(Zr) (right). 6 of 18

Figure S5. Left: Thermo-gravimetric analysis (TGA) profiles of F-azo-MIL-53(Al) (black line) and linker L (orange line) in air at 5 K/min heating rate. Right: TGA profiles of as synthesized F-azo-UiO-66(Zr) (F-azo-UiO-66(Zr)as, black), after removing DMF by thermal treatment at 280 o C under He flow (F-azo-UiOact, green) and of the dicarboxylic linker L (orange), all in air at a heating rate of 5 K/min. Horizontal dotted-lines indicate the used values to calculate the % weight loss due to linker combustion. (Dashed lines display the registered temperature changes (right axis) indicating exothermic ( T > 0) or endothermic ( T < 0) processes associated to the mass loss.) Table S1. Experimental (grey shaded) and calculated values for F-azo-MIL-53(Al) and F-azo-UiO-66(Zr) of % weigh loss due to combustion of organic linker. Material % Weight loss a Al(OH)L 85 F-azo-MIL-53(Al) 83 Zr 6O 4(OH) 4L 6 70 Zr 6O 4(OH) 4L 5 66 Zr 6O 4(OH) 4L 4 61 F-azo-UiO-66(Zr) 63 a SEM-EDX analyses revealed that the residues contain no F, thus % weight loss is calculated assuming Al 2O 3 and ZrO 2 as the only residues. 7 of 18

Inductively coupled plasma (ICP) analysis: approximately 50 mg of MOF sample were destructed in 4.5 ml of 30% HCl + 1.5 ml of 65% HNO 3 + 1.0 ml of 40% HF using microwaves. After destruction the samples were diluted to 50 ml with Milli-Q. Experiments were performed on a PerkinElmer Optima 5300 at the Section Radiation and Isotopes in Health (RIH, TU Delft). Tables S2. Calculated and experimental elemental composition of F-azo-MIL-53(Al) and F-Azo-UiO-66(Zr) in their activated or hydrated forms. MOF/H2O molar ratios as well as Zr6O4(OH)4/L ratios were estimated from TGA experiments. Al C H F N O Al(OH)L 7.74 48.29 2.01 10.91 8.05 22.98 Al(OH) H 2O 7.37 45.91 2.46 10.38 7.65 26.23 EA/ICP 8.04 a 45.8±0.2 b 2.52±0.04 b 7.54±0.04 b 22.7±0.8 a From ICP analysis. b From elemental analysis (EA). L= C 14H 6F 2N 2O 4. Zr C H F N O Zr 6O 4(OH) 4L 4.5 26.72 36.94 1.66 9.28 6.83 21.87 Zr 6O 4(OH) 4L 4.5 20H 2O 22.72 31.42 2.95 7.10 5.23 30.56 EA/ICP 25.5 a 30.50±0.03 b 2.65±0.05 b 5.2±0.2 b a From ICP analysis. b From EA. L= C 14H 6F 2N 2O 4. Figure S6. Homogeneous texture detected for F-azo-MIL-53(Al) (left) and for F-azo-UiO-66(Zr) (right) by SEM in back scattering composition (BEC) mode. 8 of 18

4. Photoisomerization studies Irradiation conditions: experiments were performed using either a LOT-Oriel 1000 W mediumpressure Xenon lamp equipped with band-pass filters (for the following experiments: UV-Vis absorbance spectroscopy of L in solution, diffuse reflectance UV-Vis spectroscopy, and composition at the photostationary states (PSSs) of the F-azo-MOFs), or with a Newport arc Xe lamp (150 W, model 71225) equipped with an optical fiber and cut-off filters (for the following experiments: DRIFT spectroscopy and gas uptake photomodulation of the F-azo-MOFs). For the latter, the light power was measured (see Figure S7) with an Avantes high-resolution spectrometer AvaSpec-USL3648. Figure S7. Newport arc Xe lamp emission spectrum with no filter (black line) and equipped with a 500 nm cutoff filter measured at 1 cm distance from the optical fiber end (green line). Figure S8. PXRD of F-azo-UiO-66(Zr) before irradiation (black line) and after 3 h of > 500 nm light followed by 3 h of 405 nm light (red line), demonstrating full retention of crystallinity through a switching cycle. 9 of 18

Figure S9. PXRD of F-azo-MIL-53(Al) before irradiation (black line) and after > 500 nm irradiation for 6 h (green line). Figure S10. PXRD of F-azo-MIL-53(Al) before irradiation (black line) and after > 300 nm irradiation for 7 h (blue line). 10 of 18

Figure S11. Diffuse reflectance UV-Vis spectra converted to Kubelka-Munk function of F-azo-MIL-53(Al) before and after 80 min > 500 nm irradiation (black line and green line, respectively) and subsequent thermal treatment at 60 C overnight (dashed red line). Figure S12. Diffuse reflectance UV-Vis spectra converted to Kubelka-Munk function of F-azo-UiO-66(Zr) before and after 40 min > 500 nm irradiation (black line and green line, respectively) and subsequent thermal treatment at 60 C overnight (dashed red line). 11 of 18

Figure S13. Diffuse reflectance UV-Vis spectra converted to Kubelka-Munk function of as-synthesized F-azo- UiO-66 diluted in BaSO4 (grey line), and upon alternating 10 min irradiation with green, blue, 310 nm, and 365 nm light (see also Figure 3c in the manuscript). Figure S14. Evolution of the Diffuse reflectance UV-Vis spectra converted to Kubelka-Munk function of F-azo- UiO-66(Zr), first irradiated with green light for 30 min to reach the PSS (green line), and then kept in the dark for 20 h (grey line), highlighting the good thermal stability of the Z isomers. 12 of 18

Figure S15. Photochromic change from orange to yellow (characteristic of azobenzenes' E Z isomerization) on the illuminated spot of F-azo-UiO-66(Zr) in a reflectance powder holder. Digestion of the MOFs: 5 mg of F-azo-UiO-66(Zr) were suspended in 0.8 ml of d6-dmso and irradiated upon gentle stirring. The samples were digested by adding 15 drops of D2SO4 followed by sonication for 20 min. as synthesized green light blue light heblduio-310nm.010.001.1r.esp -121.12 heblduio-365nm.010.001.1r.esp 310 nm 365 nm -121.55-121.57 2.5 2.5 Normalized Intensity 2.0 1.5 Normalized Intensity 2.0 1.5 1.0 0.5 0-119.10 0.5 13 % Z 14 % Z 0 14.85 100.00 1.0-119.55 16.74 100.00 0-20 -40-60 -80-100 -120-140 -160-180 -200-220 Chemical Shift (ppm) 0-20 -40-60 -80-100 -120-140 -160-180 -200-220 Chemical Shift (ppm) Figure S16. 19 F NMR in d6-dmso of a D2SO4 digestion of ca. 3 mg of F-azo UiO-66(Zr) as synthesized (top left), and after irradiating the suspensions at different wavelengths. The irradiation time was set to 3 h to ensure that the PSSs were reached. 13 of 18

Figure S17. Kinetic experiment comparing the thermal half-life of (Z)-L at 50 C with (τ 1/2 = 9.0 h) or without (τ 1/2 = 9.1 h) sulfuric acid. Figure S18. DRIFT spectra of MeL (blue) and L (black). 14 of 18

Figure S19. DRIFT spectra of activated F-azo-MIL-53(Al) (left) and F-azo-UiO-66(Zr) (right), before (black line) and after (green line) green light (> 500 nm) irradiation (40 min for F-azo-MIL-53(Al), 10 min for F-azo-UiO- 66(Zr). 5. CO2 uptake experiments A home-made adsorption cell composed of a quartz bulb and an extra tube to accommodate the optical fiber (Figure S20) was used for the in-situ irradiation during CO 2 adsorption experiments. Figure S20. Home-made gas adsorption cell (left) and detail of the setup for the in-situ irradiation during CO2 adsorption experiments (right). 15 of 18

Figure S21. CO2 adsorption isotherms (mmol CO2 per gram sample) of NH2-MIL-53(Al) (left, circles) vs F-azo-MIL- 53(Al) (left, triangles), and of UiO-66(Zr) (right, circles) vs F-azo-UiO-66(Zr) (right, triangles). Blue lines display the gas uptake per g of metal calculated according to their molecular formula. Figure S22. CO2 adsorption isotherms (273 K) of F-azo-UiO-66(Zr) before (black line) and during in-situ > 500 nm irradiation (green line). 16 of 18

Figure S23. Ex-situ CO2 adsorption isotherms (273 K) of F-azo-MIL-53(Al) (left) and F-azo-UiO-66(Zr) (right). Black line: before irradiation, green-line: after (ex-situ) green light irradiation (3 h for F-azo-MIL-53(Al), 1.5 h for F-azo-UiO-66 (Zr)). Figure S24. CO2 adsorption isotherms of F-azo-MIL-53(Al) at 0 C before irradiation (black) and during in-situ irradiation with > 500 nm light (green) and at 10 C in the dark (red). Filled and empty symbols represent adsorption and desorption data, respectively. 17 of 18

Figure S25. CO2 adsorption isotherms of F-azo-MIL-53(Al) at 0 C before irradiation (black), during in-situ > 400 nm irradiation (blue), and back in the dark (grey). Filled and empty symbols represent the adsorption and desorption data, respectively. [1] A. Altomare, C. Cuocci, C. Giacovazzo, A. Moliterni, R. Rizzi, N. Corriero and A. Falcicchio, J. Appl. Cryst., 2013, 46, 1231-1235. 18 of 18