Supporting Information

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1 This journal is The Royal Society of Chemistry Supporting Information Probing the adsorption performance of the hybrid porous MIL-68(Al): A synergic combination of experimental and modelling tools Qingyuan Yang, a,b Sébastien Vaesen, c Muthusamy Vishnuvarthan, d Florence Ragon, e Christian Serre, e Alexandre Vimont, d Marco Daturi, d Guy De Weireld,* c Guillaume Maurin* b a State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 9, China b Institut Charles Gerhardt Montpellier, UMR CNRS 55, UM, ENSCM, Place E. Bataillon, 95 Montpellier cedex 5, France. guillaume.maurin@univ-montp.fr c Faculté Polytechnique de Mons, Université de Mons, Place du Parc, 7 Mons, Belgium guy.deweireld@umons.ac.be d Laboratoire Catalyse et Spectrochimie, ENSICAEN, Université de Caen, CNRS, 6 Bd Maréchal Juin, 5 Caen cedex, France e Institut Lavoisier, UMR CNRS 88-Université de Versailles St Quentin en Yvelines, 5 avenue des Etats-Unis, 785 Versailles, France S

2 This journal is The Royal Society of Chemistry. Characterization of the synthesized MIL-68(Al) sample. X-Ray diffraction (XRD) Phase identification and crystallinity check up of the phase were performed using a Siemens diffractometer D5, it is a theta/theta diffraction instrument operating in reflection geometry using Cu Kalpha radiation ( =.556Å). Fig. S shows the corresponding XRD powder pattern of the activated MIL-68(Al) product. Intensity (a.u.) Theta Fig. S Experimental XRD powder pattern of the activated MIL-68(Al) sample.. Infra-Red (IR) Spectroscopy Fig. S shows the IR spectra, performed using a Nicollet spectrometer, of the activated product. The Infrared spectra clearly shows the presence of the vibrational bands characteristic of the carboxylates groups (ν C=O ) at around and 55cm - confirming the presence of the dicarboxylate within MIL- 68(Al). No bands corresponding to the DMF (~65cm - ) are observed but a band around 7cm - indicates there is still the presence of free acid in the material. S

3 This journal is The Royal Society of Chemistry Transmittance (%) Wavenumber (cm - ) Fig. S IR spectra of the activated MIL-68(Al) sample.. Thermo gravimetric analysis (TGA) Two weight-loss steps were observed on the TGA curve, performed using a Perkin Elmer, STA 6 instrument: first the departure of the guest molecules (H O, MeOH and DMF) in the range 98 6 K (8.5%); the second one around 77 K is due to the decomposition of the framework to produce Al O and associated with the departure of the organic linker (experimental: 67.8%; calculated: 69.5%). Fig. S TGA curve of activated MIL-68(Al) product under O (heating rate of K per minute) (5mg of solid). S

4 This journal is The Royal Society of Chemistry. Nitrogen porosimetry Typical nitrogen sorption isotherm at 77K has been performed on the material after a treatment under primary vacuum at K overnight (BEL Japan, BELSORP Prep). A BET specific surface area of () m.g - is obtained. 6 V a /cm (STP) g p/p Fig. S Nitrogen adsorption isotherm of the MIL-68(Al) at T = 77 K (p = atmosphere). S

5 This journal is The Royal Society of Chemistry. Atomic partial charges obtained by DFT calculations. Model Cluster and atomic partial charges of MIL-68(Al) Al O H O C C C H Fig. S5. Cluster used for calculating the partial charges on MIL-68(Al) atoms. To minimize the boundary effects, the terminal Al atoms were saturated with two methoxyl and one hydroxyl groups, while other terminations were saturated by methyl groups. Table S. Atomic partial charges for the MIL-68(Al) structure derived on DFT/PBE Level. Atomic types Al O O C C C H H Charge (e) S5

6 This journal is The Royal Society of Chemistry. Model cluster and atomic partial charges of MIL-68(Al)-NH H5 H Al O O C8 H C5 N C6 H6 C7 C O C C C H H Fig. S6. Cluster used for calculating the partial charges on MIL-68(Al)-NH atoms. To minimize the boundary effects, the terminal Al atoms were saturated with two methoxyl and one hydroxyl groups, while other terminations were saturated by methyl groups. Table S. Atomic partial charges for the MIL-68(Al)-NH structure derived on DFT/PBE Level. Atomic types Al O O O C C C C C5 C6 Charge (e) Atomic types C7 C8 H H H H H5 H6 N Charge (e) S6

7 This journal is The Royal Society of Chemistry. Mulliken partial charges for the MIL-68(Al) obtained by periodic DFT calculation Table S. Mulliken partial charges for the MIL-68(Al) structure derived on DFT/PW9 Level. Atomic types Al O O C C C H H Charge (e) Adsorption isotherms. Experimental adsorption isotherms at K CH uptake (mmol/g) Outgassed at K Outgassed at 5 K Activated at 6 K under air flow Pressure (bar) a) CO uptake (mmol/g) 8 6 b) Outgassed at K Outgassed at 5 K Activated at 6 K under air flow 5 6 Pressure (bar) S7

8 This journal is The Royal Society of Chemistry H S uptake (mmol/g) 8 6 Outgassed at K Outgassed at 5 K c) 6 8 Pressure (bar) Fig. S7. Influence of the activation temperature on the absolute adsorption isotherms in the MIL-68(Al) at K: (a) CH, (b) CO and (c) H S.. Simulated adsorption isotherms of N in the MIL-68(Al) at K 8 f) N uptake (mmol/g) 6 Without Blocking Blocking 5 6 Pressure (bar) Fig. S8 Effect of blocking the triangular pores on the simulated absolute adsorption isotherms of N in the MIL-68(Al) solid at K. These results were obtained using ESP charges combined with DREIDING forcefield. S8

9 This journal is The Royal Society of Chemistry. Microscopic adsorption mechanism of CO in the MIL-68(Al) at K a) P =. bar b) P =. bar c) P =. bar d) P = 5. bar Fig. S9. Contour plots of the probability density distributions of the COM of CO in MIL-68(Al) at different pressures, viewed along the direction of the channels. S9

10 This journal is The Royal Society of Chemistry 5. Radial Distribution Functions (RDFs) and snapshots in the MIL-68(Al) with the triangular channels blocked 5. RDFs and snapshot for CO molecules 5 O CO -H OH. bar. bar. bar 5. bar a) b) 6 8 c) Fig. S. (a) RDFs of CO molecules around the H atoms of the OH groups (denoted as H OH ) in the hexagonal channels in the MIL-68(Al) at different pressures, (b) One typical snapshot for the CO molecules adsorbed at. bar, where a close-up view of the part marked with the yellow circle is shown in (c). These results were obtained from the simulations with blocking the triangular channels. S

11 This journal is The Royal Society of Chemistry 5. RDFs and snapshot for H S molecules 6 5. bar. bar. bar. bar a) S H S -H OH 6 5. bar. bar. bar. bar H H S -O OH b) d) c) Fig. S. RDFs of the (a) S atoms in the H S molecules around the H atoms (denoted as H OH ) and (b) H atoms in the H S molecules around the O atoms (denoted as O OH ) of the OH groups in the hexagonal channels in the MIL-68(Al) at different pressures; (c) One typical snapshot for the H S molecules adsorbed at. bar, where a close-up view of the part marked with the yellow circle is shown in (d). These results were obtained from the simulations by blocking the triangular channels. S

12 This journal is The Royal Society of Chemistry 6. RDFs calculated in the MIL-68(Al) without blocking the triangular channels. bar. bar. bar 5. bar CH -H OH a). bar. bar. bar 5. bar b) CH -H OH 6 8. bar. bar. bar 5. bar N N -H OH c) 6 8. bar. bar. bar 5. bar N N -H OH d) Fig. S. RDFs of the CH (a, b) and N (c, d) molecules around the H atoms of the OH groups in the triangular (denoted as H OH ) and hexagonal (denoted as H OH ) channels in the MIL-68(Al) at different pressures. These results were obtained from the simulations without blocking the triangular channels. S