A Third Generation Breathing MOF with Selective, Stepwise, Reversible and Hysteretic Adsorption properties

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1 Supporting information for A Third Generation Breathing MOF with Selective, Stepwise, Reversible and Hysteretic Adsorption properties Suresh Sanda, Srinivasulu Parshamoni and SanjitKonar* Department of Chemistry, IISER Bhopal, Bhopal , India. Fax: ; Tel: ; skonar@iiserb.ac.in Experimental section: Materials. All the reagents and solvents for synthesis were purchased from commercial sources and used as supplied without further purification. All the Metal Salts, 2,3,5,6- Benzene tetracarboxylic acid (Pyromellitic acid) and Aldrithiol were obtained from the Sigma-Aldrich Chemical Co. India. Synthesis of {[Zn(C 10 H 2 O 8 ) 0.5 (C 10 S 2 N 2 H 8 ).5H 2 O)]} n (1). An aqueous solution of (5mL) Na salt of pyromellitate (0.05mmol, 17.1mg) was mixed with acetonitrile solution (5mL) of aldrithiol (0.1mmol, 22mg) and the resulting solution was stirred for 1 hour to mix well. Zn(NO 3 ) 2.6H 2 O (0.1mmol,29.7mg) was dissolved in 10 ml of water. 2 ml of the above mixed ligand solution was slowly and carefully layered on 2 ml of this metal solution by using 1 ml of 1:1 (H 2 O:CH 3 CN) solution as a buffer. X-ray quality colorless, rectangular shaped single crystals were obtained after 15 days. The crystals were separated and washed with acetonitrile and air-dried (Yield 40% based on metal). Elemental analysis: Anal. Cald.C-35.97%, N-5.59%, S-12.80%, H-3.82%, Found: C, 36.08%, N, 5.62%, S, 12.50%, H, 3.34%. FT-IR(KBr pellet, cm -1 ) (br), (s), (s), (s), (w), (w), (m), (m). Sorption measurements: Gas adsorption measurements were performed by using BelSorpmax(BEL Japan) automatic volumetric adsorption instrument. All the gases used were of Ultra-pure research grade (99.999%). HPLC grade solvents were used for vapor adsorption studies. Before every measurement sample was pretreated for 12hrs at 373 K under 10-2 KPa continuous vacuum using BelPrepvac II and purged with N 2 on cooling. CO 2, CH 4 isotherms were measured at 195 K (Dry ice-meoh cold bath). CO 2 isotherms also

2 recorded at 230 K (Dry ice-ethylene glycol(60%)-ethanol(40%) mixture), 259 K, 265 K & 273 K (Julabo chiller with Ethylene glycol-water mixture as a coolant). Physical measurements: Thermo gravimetric analysis was recorded on Perkin-Elmer TGA 4000 instrument in the temperature range of C under N 2 atmosphere with heating rate of 10 C/min. IR spectrum of the compound 1 was recorded on Perkin-Elmer FT-IR Spectrum BX using the KBr pellets in the region cm -1. Elemental analysis was carried out on Elementar Micro vario Cube Elemental Analyzer. PXRD patterns were measured on PAnalytical EMPYRIAN instrument by using Cu-K radiation. X-ray Single-Crystal structure Determination: Single crystal data for compound 1 was collected on a Bruker APEX II diffractometer equipped with a graphite monochromator and Mo-K ( = Å, 296 K) radiation. Data collection was performed using and scan. The structure was solved using direct method followed by full matrix least square refinements against F 2 (all data HKLF 4 format) using SHELXTL. Subsequent difference Fourier synthesis and least-square refinement revealed the positions of the remaining nonhydrogen atoms. Determinations of the crystal system, orientation matrix, and cell dimensions were performed according to the established procedures. Lorentz polarization and multi-scan absorption correction were applied. Non-hydrogen atoms were refined with independent anisotropic displacement parameters and hydrogen atoms were placed geometrically and refined using the riding model.

3 Summary of crystallographic data for compound 1 Empirical Formula C15H19 N2 O9 S2 Zn Chemical formula weight Crystal shape block Color white Size Crystal system Triclinic Space group P-1 Cell length a 9.042(2) Å Cell length b (3) Å Cell length c (3) Å Cell angle alpha (10) Cell angle beta (9) Cell angle gamma (9) Cell volume V (4) Å 3 Cell formula units Z 2 Wave length Å Temperature (K) 296(2) Theta range for data collection 2.45 to Index ranges -11<=h<=11, -14<=k<=14, -14<=l<=14 Goodness-of-fit R factor all WR crystal_f_

4 Figure S1: TGA Plot of compound 1. Figure S2: PXRD patterns of 1 (a) Simulated (green) (b) As synthesized (red).

5 De-solvated As Syn Figure S3: PXRD patterns of (a) As synthesized (black) (b) De-solvated compound 1(red). Figure S4: H 2 (77K) and CH 4 (195K) isotherms of compound 1.

6 Figure S5: Isosteric heat of adsorption for compound 1 obtained from CO 2 sorption data at 273K and 298K. Figure S6: Isosteric heat of adsorption for compound 1 obtained from H 2 sorption data at 77 K and 87 K.

7 Figure S7: Isosteric heat of adsorption for compound 1 obtained from CH 4 adsorption data at 298 K and 273 K. Figure S8: CO 2 adsorption isotherms in the temperature region of 195 K to 298 K. 230 K (red), 259 K(blue), 265 K(black), 273 K(green), 298 K(magneta). At 265 K and 0.20 bar the isotherm shows a distinct adsorption step and the uptake amount is 4.0 wt%. Interestingly, the corresponding desorption curve followed nearly the same pathway and is completely closed to rejoin the adsorption isotherm, revealing all of the adsorbed CO 2

8 molecules can be removed from the host framework at this temperature. However, from the adsorption isotherm at 259 K it is difficult to judge a true step in the isotherm because it shows slight deviation in the shape of the curve compared to the one at 265 K and the uptake amount increased to 4.5 wt%. The isotherm at 230 K exhibits the steps similar to the isotherm at 195 K, but the first step is less distitinct and the P/P 0 values for the respective steps are slightly lower (0.17 & 0.4 bar) compared to 195 K and the uptake amount increased to 10 wt% in this case. Figure S9: Isosteric heat of adsorption for compound 1 obtained from CO 2 sorption data at 265 K and 273 K.

9 Figure S10: PXRD patterns of different organic solvent exposed samples after complete adsorption steps.

10 Figure S11: View of the (010) crystallographic plane.