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1 Electronic Supplementary Material (ESI) for Chemical Communications. This journal is The Royal Society of Chemistry 2016 Electronic Supplementary Information CO 2 capture enhancement in InOF-1 via a bottleneck effect of confined ethanol Ricardo A. Peralta, a Alberto Campos-Reales-Pineda, a Heriberto Pfeiffer, a J. Raziel Álvarez, a J. Antonio Zárate, a Jorge Balmaseda, a Eduardo González-Zamora, *,b Ana Martínez, a Diego Martínez-Otero, c Vojtech Jancik *,c and Ilich A. Ibarra *,a a Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, CU, Del. Coyoacán, 04510, Ciudad de México, Mexico. argel@unam.mx b Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, C. P , Ciudad de México, Mexico. egz@xanum.uam.mx c Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carr. Toluca- Atlacomulco Km 14.5, Toluca, Estado de México 50200, México. Personal del Instituto de Química de la UNAM. vjancik@unam.mx

2 1. Crystal Structure Determination Fig. S1: (left) View of the binuclear building block of two metal ions oxygen octahedra bridged by a μ 2 -hydroxo group, (centre) crystal structure of InOF-1 along c axis showing 7.5 Å channels and (right) the BPTC 4- ligand. Table S1. Selected crystallographic data for InOF-1A and InOF-1B. InOF-1A InOF-1B formula C 8 H 4 InO 5 C 10 H 10 InO 6 fw crystal system tetragonal tetragonal space group I I temp, K 100(2) 100(2) λ, Å a, Å (7) (2) b, Å (7) (2) c, Å (6) (3) V, Å (3) (10) Z 8 8 ρ, g cm μ, mm F(000) crystal size, mm x x x x Θ range, deg to to no. of reflns Indep. reflns (R int ) 1517 (0.0433) 1769 (0.0276) no. of data / restr. / param / 9 / / 92 / 130 GoF on F R 1, a wr b 2 (I > 2σ(I)) , , R 1, a wr b 2 (all data) , ,

3 abs. struct. par. 0.10(6) 0.15(6) Residuals, e Å / / Voids in the unit cell: Volume, Å 3 / electrons 1504 / / 188 a R 1 = F o F c / F o. b wr 2 = [ w(f o 2 F c 2 ) 2 / (F o 2 ) 2 ] 1/2. Table S2. Selected bond lengths (Å) and angles ( o ) for InOF-1A and InOF-1B. InOF-1A InOF-1B In(1) O(3) 2.108(8) 2.097(6) In(1) O(1) 2.128(2) 2.137(2) In(1) O(2A) 2.160(2) 2.172(3) O(1) C(5) 1.271(4) 1.271(5) O(2) C(5) 1.260(5) 1.254(5) C(1) C(2) 1.386(5) 1.401(4) C(1) C(1B) 1.513(10) 1.483(9) C(2) C(3) 1.408(5) 1.404(5) C(3) C(4) 1.391(5) 1.395(4) C(3) C(5) 1.482(5) 1.479(5) In(1C)-O(3)-In(1) 119.8(3) 119.1(2) O(3)-In(1)-O(1D) 94.8(7) 97.0(2) O(3)-In(1)-O(1E) 178.1(8) 177.8(2) O(1F)-In(1)-O(1) 83.4(1) 82.9 (1) O(3)-In(1)-O(2A) 87.6(5) 86.3(2) O(1)-In(1)-O(2A) 92.0(1) 91.2(1) O(1)-In(1)-O(2G) 92.7(1) 91.4(1) O(2A)-In(1)-O(2C) 173.7(2) 176.5(2) O(2)-C(5)-O(1) 127.3(4) 126.5(4) O(2)-C(5)-C(3) 117.4(3) 118.0(3) O(1)-C(5)-C(3) 115.3(4) 115.4(3) Symmetry operators used to generate equivalent atoms: InOF-1A: A x+ 3 / 2,y, z+ 3 / 4 ; B y,x, z; C,G y, x+ 3 / 2,z+ 1 / 4 ; D,F y,x, z+1; E x,y,z. InOF-1B: A,G y+1,x+ 1 / 2,z+ 1 / 4 ; B y,x, z; C x+ 1 / 2,y, z+ 3 / 4 ; D x,y,z; E,F y+1, x+1, z Experimental All reagents and solvents were used as received from commercial suppliers without further purification. Powder X-ray diffraction (PXRD) data were collected under ambient conditions on a Bruker AXD D8 Advance diffractometer operated at 1600 W (40 kv, 40 ma) for Cu Kα 1 (λ= Å). Thermal gravimetric analysis (TGA) was performed under N 2 at a scan rate of 2 C/min using a TA Instruments Q500HR analyser. Chemicals. Indium nitrate (In(NO 3 ) 3 ), biphenyl-3,3,5,5 -tetracarboxylic acid (H 4 BPTC), N,N-dimethylformamide (DMF), acetonitrile (CH 3 CN), nitric acid (65%, HNO 3 ), anhydrous ethanol (<0.005% water) and ethanol (reagent grade alcohol, 95%) were purchased from Sigma-Aldrich and used as received.

4 Material Synthesis. InOF-1 was synthesised according to previously reported procedures: 1 In(NO 3 ) 3 (156 mg, 0.40 mmol) and H 4 BPTC, (33 mg, 0.10 mmol) were dissolved in CH 3 CN (5 ml), DMF (5 ml) and HNO 3 (65 %, 0.2 ml) and sealed in a pressure tube. The clear solution was heated at 85 o C in an oil bath for 72 h. The tube was cooled to room temperature over a period of 12 h and the colourless crystalline product was separated by filtration, washed with DMF (5 ml) and dried in air. Yield: 72 % (based on ligand). Desolvation of InOF-1. Samples of as-synthesised solvated InOF-1 were placed in acetone for four days followed by degassing at 180 o C and bar (or under a flow of N 2 ) for two h to afford the fully desolvated materials. Adsorption Isotherms for N 2, CO 2 and EtOH. N 2 isotherms (up to 1 bar and 77 K) were recorded on a Belsorp mini II analyser under high vacuum in a clean system with a diaphragm pumping system. CO 2 isotherms up to 16 bar and 30 o C, were recorded on a Belsorp HP (High Pressure) analyser. EtOH isotherms (at 20 and 30 o C) were recorded in a DVS Advantage 1 instrument from Surface Measurement System. Ultra-pure grade ( %) N 2 and CO 2 gases were purchased from PRAXAIR. Adsorption Microcalorimetry for EtOH. Ethanol adsorption microcalorimetry experiments were carried out at 30 o C using approximately 400 mg of sample (InOF-1). The evolved heat was measures using a Tian-Calvet microcalorimeter (CA-100, ITI). This instrument measures the ethanol isotherm and the enthalpy of adsorption for ethanol simultaneously using a point by point introduction of vapour to the sample. Previous any adsorption experiment, the sample of InOF-1 was activated at 180 o C under vacuum (10-5 bar). Kinetic CO 2 Uptake Experiments. Kinetic experiments were performed by using a thermobalance (Q500 HR, from TA) at 30 o C with a constant CO 2 flow (60 ml min 1 ). Single Crystal X-ray Diffraction Experiments. Single crystals of InOF-1 were obtained by slowly cooling of the reaction mixture after its synthesis. These crystals were first washed with acetone to remove most of the uncoordinated DMF and water from the channels. However, it was not possible to remove all DMF in this way. Therefore, several crystals were selected and placed inside a vial into a Büchi drying tube and exposed to a high vacuum at 170 o C for three hours to assure a total elimination of any solvent from the voids. During this time, the vacuum rose from to bar. One of such dried crystals was submerged in Paratone oil to protect it from moisture and used for the data collection. The rest of the crystals were soaked in ethanol (anhydrous ethanol, <0.005% water) that was freshly dried over potassium and distilled under reduced pressure in a sealed system to exclude any possible contamination with water. One of these crystals was used for data collection. Selected crystals were mounted on a Bruker APEX DUO diffractometer equipped with an Apex II CCD detector at 100 K. Frames were collected using omega scans 2 and integrated with SAINT. 2 Multi-scan absorption correction (SADABS) 2 was applied. The structures were solved by intrinsic phasing (SHELXT) 3 and refined using full-matrix least-squares on F 2 with SHELXL 4 within the ShelXle GUI. 5 Weighted R factors, R w, and all goodness-of-fit indicators, are based on F 2. All non-hydrogen atoms were refined anisotropically. The hydrogen atoms of the C H bonds were placed in idealized positions, whereas the hydrogen atom from the OH moiety was localized from the difference electron density map and its position was refined with U iso tied to the parent atom with distance restraint (DFIX). The

5 disordered ethanol molecule in InOF-1B was refined using geometry (DFIX, SAME) and U ij restraints (SIMU, RIGU) implemented in SHELXL. 4 The molecular graphics were prepared using Mercury and GIMP. 6 To prepare the model without a disorder, the structure was expanded to a P4 1 space group. The surface of the channels was calculated with probe radius 1.2 Å, grid spacing 0.2 Å within Mercury. 6a,7 CCDC and contain the supplementary crystallographic data for this paper. Copies of the data can be obtained free of charge via or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) ; deposit@ccdc.cam.ac.uk). Computational Details. Geometric optimisations and single point calculations were performed using Gaussian 09 implementation. 8 The geometry of the model was fully optimised with B3LYP functional 9 using LANL2DZ for metal atoms and D5DV basis sets for light atoms. 10 In order to verify optimised minima, harmonic analyses were performed identifying local minima (zero imaginary frequencies). The Molecular Electrostatic Potential (MEP) of a molecule is a good reference to assess the reactivity of the molecules towards positively or negatively charged reactants. MEP is obtained using the total electron density to analyse the force acting on a positive test charge located in the vicinity of a molecule. It is important to note that no polarisation of the molecule occurs and therefore, the molecular charge distribution remains undisturbed through the external test charge. CO 2 Separation Experiments. A catalytic reactor system (BEL-REA, BEL Japan) coupled to a Bruker TENSOR 27 FTIR was employed to measure the CO 2 column separation at 30 o C. 3. TGA Plot Fig. S2: TGA analysis of acetone-exchanged InOF-1 (blue line).

6 4. Powder X-ray Diffraction Patterns Fig. S3: PXRD patters of calculated (black), as-synthesised (red) and desolvated (blue) of InOF CO 2 Capture Studies (a) (b) Fig S4: (a) Kinetic CO 2 uptake experiments performed at 30 o C with a CO 2 flow of 60 ml min 1 in InOF-1 (red curve), impregnated InOF-1 (10% of the pore volume filled with EtOH, blue curve) and saturated InOF-1 (85% of the pore volume filled with EtOH, green curve); (b) reproducibility of the CO 2 experiments of impregnated InOF-1. Six different samples were impregnated with EtOH (300 mg of an activated InOF-1 sample were carefully impregnated with ml of EtOH, with the help of a micropipette) and kinetic CO 2 experiments were carried out. The average of the total CO 2 capture of the six experiments is wt%.

7 6. Solvent Wet Impregnation Method Acetone-exchanged samples of InOF-1 were activated at 180 o C for 2 h and under a flow of N 2 using a thermobalance (Q500 HR, from TA). When the activation was completed, the temperature was cooled down to 30 o C (always under a flow of N 2 ) and then, these samples were partially filled, their pore volume, with ethanol as follows: Impregnated InOF-1 (10% EtOH loaded InOF-1): The pore volume of the material InOF-1 is cm 3 g 1, thus the 10% of that pore volume is equal to cm 3 g 1. Then, 300 mg of an activated InOF-1 sample were carefully impregnated with ml of EtOH (with the help of a micropipette). Saturated InOF-1 (85% EtOH loaded InOF-1): The pore volume of the material InOF-1 is cm 3 g 1, thus the 85% of that pore volume is equal to cm 3 g 1. Then, 300 mg of an activated InOF-1 sample were carefully impregnated with ml of EtOH (with the help of a micropipette). 7. PXRD after CO 2 Experiments Fig. S5: Calculated PXRD pattern of InOF-1 and PXRD patterns of each InOF-1 samples after the kinetic and static CO 2 experiments.

8 8. Ethanol Adsorption Experiments Fig. S6: Ethanol adsorption isotherm at 30 o C of InOF-1 from %P/P 0 = 0 to 90. Solid circles represent adsorption, and open circles show desorption. The inset shows the ethanol sorption isotherm at 30 o C from %P/P 0 = 0 to 20. Fig. S7: Ethanol adsorption isotherm at 20 o C of InOF-1 from %P/P 0 = 0 to 90. Solid circles represent adsorption, and open circles show desorption. The inset shows the ethanol sorption isotherm at 20 o C from %P/P 0 = 0 to 20.

9 9. Adsorption Microcalorimetry for EtOH Fig. S8: EtOH adsorption isotherm of InOF-1 generated during the microcalorimetric experiment at 30 o C. Fig. S9: Differential enthalpy of adsorption of EtOh vs. loading determined by microcalorimetry on InOF-1 at approximately 30 o C.

10 10. Molar Enthalpy of Adsorption for Ethanol (Fowler-Guggenheim type Adsorption Isotherm, FGAI)

11

12

13 Ethanol adsorption isotherms analysis The model fitted is shown in Fig. S11 and Fig. S12: Fig. S10: Experimental adsorption isotherms in the low covering region. Natural cubic splines connect points for easy viewing.

14 Fig. S11: Experimental adsorption isotherm at 20 o C (black circles) and equation (2) fitted (red pointed line). Fig. S12: Experimental adsorption isotherm at 30 o C (black circles) and equation (2) fitted (red pointed line).

15 Nonlinear regression to estimate the parameters K(T) and b(t) of the equation (2) were performed using the fit command implemented in GNUPLOT version 4.6. The isosteric heat of adsorption was calculated for a series of coverage using the isotherms collected at 20 o C and 30 o C, and the algorithm implemented in the DVS Advanced Analysis Suite version provided by from Surface Measurement Systems Ltd UK. Fig. S13: Molar enthalpy of adsorption (ΔH) vs volume filling (ϑ).

16 11. Ethanol adsorption-desorption recyclability Fig. S14: Ethanol readsorption-desorption uptake on InOF-1 at 30 0 C. 12. Cycle Stability Fig. S15: Calculated PXRD pattern of InOF-1 and PXRD pattern of InOF-1 after the 4 cycles of EtOH adsorption-desorption.

17 13. Computational Studies Scheme S1: Schematic representation of the model that was used. In order to investigate the relationship between the presence of ethanol (confined into InOF- 1) and its affinity towards CO 2, a model of the binuclear [In 2 (μ 2 -OH)] building block (reactive section) was taken and the geometry was optimised (see experimental, computational details). In Scheme S1, the schematic representation of the molecular section (binuclear building block) under study is presented. Since the most representative section of the model is related to the μ 2 -OH group, this is emphasised in the scheme (Scheme 1) in red. In the proposed model, each In(III) metal centre is coordinated by six oxygen atoms. Fig. S16 shows the optimised molecular section and its corresponding Molecular Electrostatic Potential (MEP). The red colour of the MEP is the negative section of the molecular model (high electron density) and the blue colour represents the positive section (low electron density). As it can be seen in the MEP of Fig.S16, the H atom from the μ 2 -OH group is positive (blue), so it is expected a hydrogen bond between this H atom and the oxygen atom coming from the ethanol molecule (OH-CH 2 -CH 3 ) as previously demonstrated by single crystal X-ray diffraction.

18 Fig. S16: (left); Optimised model structure and (right;) Molecular Electrostatic Potential (MEP) representation of the model. Following the information that the MEP provided and by taking into consideration the bond length of O H =1.95 Å, derived from the X-ray single crystal diffraction information, we then localised an ethanol molecule close to the μ 2 -OH group. Fig. S17 (left) shows the structure of the model with the ethanol molecule. A single point calculation of this system was performed in order to obtain the total electron density and with this, we obtained its corresponding MEP that is shown in Fig. S17 (right). Fig. S17: (left); Optimised model structure and (right); MEP of the model with one ethanol molecule located at the X-ray single crystal diffraction bond distance. According to the MEP model (Fig. S17, right), the hydrogen atom from the functional group OH from the HO CH 2 CH 3 molecule, is positive. Interestingly, the MEP of the rest of the molecular model with or without the ethanol molecule is similar. Thus, if a CO 2 molecule is added into the system, this should be hydrogen-bonded to the positive section of the ethanol molecule. To verify this hypothesis, two more molecular systems were calculated (single

19 point energy calculations). One system with a CO 2 molecule hydrogen-bonded to one H atom from the aliphatic chain (CH 2 CH 3 ) of the ethanol molecule and the other where the MEP model proposes is most suitable (positive section of the molecular model). These two structures are shown in Fig. S18 (MEPs are also included). The structure with a CO 2 molecule that forms an O H O bond (Fig. S18a) is more stable than the structure with a CO 2 molecule forming an O H C bond (Fig. S18b) by almost 10 kcal mol 1. Therefore, we can conclude that a CO 2 molecule should be linked, via a hydrogen bond, to the OH group of the ethanol molecule. Fig. S18: Optimised model structures and MEPs with one ethanol molecule located at the X- ray single crystal diffraction bond distance and one CO 2 molecule. Two geometries were tested: (A) is more stable than (B) by almost 10 kcal mol 1.

20 14. Catalytic Reactor System (BEL-REA) for the CO 2 Separation Experiments Finally, in order to show the potential of confining EtOH (within the micropores of InOF-1) for a more realistic industrial application, we decided to carry out some CO 2 column separation studies. For this purpose, a catalytic reactor system (BEL-REA, Fig. S19) was used, which allowed each sample of acetone-exchanged InOF-1 to be activated (180 o C for two h) under a flow of N 2 gas and then directly exposed to a constant flow of CO 2 (in situ) and analysed by FTIR spectroscopy over many cycles. Thus, an acetone-exchanged sample of InOF-1 (200 mg) was packed into a quartz cell of the BEL-REA system (see Fig. S20) and activated as described before. Then, the system was cooled down to 30 o C and the activated sample was exposed to a CO 2 flow (0.13 mmol min 1 ). Subsequently, after stabilisation of the gas flow within the micropores of the sample, the resulting exhaust gas (outlet, see Fig. S19) was analysed by FTIR spectroscopy. Thus, a FTIR spectrum was recorded every 40 seconds (approximately 0.66 min), until the detector was saturated, to make a total of 6 FTIR spectra. The most characteristic FTIR band for CO 2 is at 2349 cm 1, Fig. S21. Clearly in Fig. S21 (left), it is possible to observe a continuous increase in the intensity of the band with time. In other words, from spectrum 1 to spectrum 6 the intensity of the characteristic FTIR band is increasing while the transmittance is decreasing. Fig. S19: Catalytic reactor system (BEL-REA) system.

21 Fig. S20: Picture of an acetone-exchanged sample of InOF-1 (200 mg) packed into a quartz cell of the BEL-REA system. Fig. S21: FTIR spectra (characteristic CO 2 band) of the resulting exit exhaust CO 2 gas: (left); InOF-1 sample and (right); impregnated InOF-1 sample.

22 Later, an acetone-exchanged sample of InOF-1 was activated (as previously described), cooled down to 30 o C (under N 2 ) and the pore volume (of InOF-1) was partially filled with ethanol (EtOH) via a solvent wet impregnation method (10% EtOH). Then, the impregnated InOF-1 sample (200 mg) was packed into a quartz cell of the BEL-REA system (Fig. S20) and gently N 2 purged to remove any absorbed moisture, the temperature set to 30 o C and exposed to a CO 2 flow (0.13 mmol min 1 ). Fig. S21 (right) exhibits the FTIR spectra (6) recorded every 40 seconds. Although the intensity of the characteristic FTIR band increases as the transmittance decreases, the increase-rate is clearly different to that of the unimpregnated InOF-1 sample (Fig. S21, left). In order to visualise these differences, by normalising the characteristic FTIR intensities it was possible to simultaneously plot the normalised intensity of each CO 2 scan for InOF-1 and impregnated InOF-1, respectively (Fig. S22). This suggests that the CO 2 molecules that go through the materials, InOF-1 or impregnated InOF-1, finally reach the FTIR detector at different times. Fig. S22: Normalised characteristic FTIR intensities from a resulting exit exhaust of CO 2 gas as a function of the number of scans. (green) InOF-1 and (blue) impregnated InOF-1. Thus, by taking the area under each transmittance spectrum (curve), it is possible to compare the increase in the area under the curve of each CO 2 scan for samples InOF-1 and impregnated InOF-1, respectively (Fig. S23). For each scan, the area under the curve of sample InOF-1 is higher than impregnated InOF-1. This suggests that the CO 2 molecules passing through the micropores of the InOF-1 sample, they effectively reach the FTIR detector before then the CO 2 molecules that travel within the micropores of the impregnated InOF-1 sample. We then rationalise these results as follows; when CO 2 gas flows through the impregnated InOF-1 sample, this material retains CO 2 stronger than the fully activated

23 material (InOF-1), and therefore, the CO 2 gas molecules flow faster inside the InOF-1 sample and these are detected earlier. Fig. S23: Area under each transmittance spectrum (curve), from a resulting exit exhaust of CO 2, as a function of the number of scans. Fig. S24: Polynomial regressions of the area under each transmittance spectrum (curve) on Fig. S23.

24 By taking the derivative of both functions for InOf-1 and Impregnated InOf-1, respectively: f(x) = x x 3 4E+06x 2 + 3E+07x + 7E+09 g(x) = x x 3 + 2E+07x 2 2E+09x + 5E+10 it is possible to plot both derivative functions (df(x)/dx and dg(x)/dx) and find the maximum of both derivates. The difference of these maximums is equal to ~ 40.7 s. Fig. S25: Derivate functions (df(x)/dx and dg(x)/dx) coming from polynomial regressions of the area under each transmittance spectrum (curve) on Fig. S24. These results corroborate that the impregnated InOF-1 material showed a much higher affinity towards CO 2 than the fully activated InOF-1 material. We interpreted this affinity as a CO 2 separation which can be seen in the time delay of the CO 2 molecules in reaching the FTIR detector. By polynomial regressions of the area under each transmittance spectrum (curve) on Fig. S25, we estimated this delay to be approximately 41 s (see Fig. S24 and Fig. S25).

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