SUPPORTING INFORMATION Reticular Chemistry at its Best: Directed Assembly of Hexagonal Building Units into the Awaited MOF with the Intricate Polybenzene Topology, pbz-mof Dalal Alezi, Ioannis Spanopoulos, Constantinos Tsangarakis, Aleksander Shkurenko, Karim Adil, Youssef Belmabkhout, Michael O Keeffe, Mohamed Eddaoudi *, and Pantelis N. Trikalitis *, Department of Chemistry, University of Crete, Voutes 71003 Heraklion, Greece; Functional Materials Design, Discovery & Development (FMD 3 ), Advanced Membranes & Porous Materials Center, Division of Physical Sciences and Engineering, 4700 King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia; School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States. Email: ptrikal@uoc.gr, mohamed.eddaoudi@kaust.edu.sa Table of Contents Methods and instrumentation Synthesis of the H 6 L ligand and NMR spectra Synthesis of pbz-mof-1 Single crystal X-ray crystallography Powder X-ray Diffraction (PXRD) Patterns Thermal Gravimetric Measurements (TGA) Structural Figures NMR measurements of acid-digested sample Additional CH 4 sorption data S2 S3 S7 S8 S10 S10 S11 S13 S14 S1
Methods and Instrumentation Starting Materials. All chemicals were purchased and used without further purification. 4- carboxyphenylboronic acid, tetrahydrofuran (THF), methanol, absolute ethanol, H 2 SO 4 (98 %), HCl (37 %), and NaOH pellets were purchased from Aldrich. Neat bromine was purchased from Merck. Hexaphenyl benzene and Pd(PPh 3 ) 4 was purchased from Alfa Aesar. Na 2 CO 3 was purchased from RDH chemical company. Single-crystal X-ray diffraction data were collected using a Bruker X8 PROSPECTOR APEX2 CCD diffractometer (Cu Kα, λ = 1.54178 Å). Indexing was performed using APEX2 (Difference Vectors method). 1 Data integration and reduction were performed using SaintPlus 6.01. 2 Absorption correction was performed by multi-scan method implemented in SADABS. 3 Space groups were determined using XPREP implemented in APEX2. 1 Structure was solved using SHELXS-97 (direct methods) and refined using SHELXL-97 (full-matrix least-squares on F 2 ) contained in APEX2. 1 Crystal data and refinement conditions are shown in Table S1. S2
Synthesis of the H 6 L ligand Figure S1. Synthesis of the hexacarboxylic acid H 6 L. Synthesis of 2. To a stirring mixture of 3.670 g (20 mmol) of 4-carboxyphenylboronic acid (1), in 30 ml of methanol, 0.15 ml of H 2 SO 4 (98 %) was added and the mixture was refluxed for 30 h. The resulting solution was evaporated to dryness; the white solid was collected by filtration, washed with water and dried in an oven. Yield = 3.379 g (99 %). 1 H-NMR (500 MHz, DMSO-d 6 ): 8.28 (br.s, 2H), 7.90 (s, 4H), 3.85 (s, 3H). S3
Figure S2. 1 H NMR spectrum of compound 2 in DMSO-d 6 (500 MHz). Synthesis of 4. In a 25 ml round bottom flask 1.0 g (2 mmol) of hexaphenylbenzene (3) was treated with 4 ml of neat Br 2, and the mixture was stirred at room temperature for 50 min. Then, chilled ethanol (-20 0 C) was added and the flask was kept at -20 0 C for 16 h. The mixture was filtered and washed with chilled ethanol. Yield = 1.836 g (96 %). 1 H NMR (500 MHz, CDCl 3 ): 7.05 (d, J = 8, 12H), 6.63 (d, J = 8, 12H). S4
Figure S3. 1 H NMR spectrum of compound 4 in CDCl 3 (500 MHz). Synthesis of 5. To a mixture of 0.950 g (0.9 mmol) of 4 in 35 ml THF and 10 ml Na 2 CO 3 2 M, 1.2 g (6.7 mmol) of 2 was added and the mixture was degassed with N 2 for 50 min. Then, 50 mg of Pd(PPh 3 ) 4 were added and the mixture was heated at 85 C under nitrogen atmosphere for 5 days. The product precipitated from the reaction mixture and isolated by filtration. The solid was washed with THF (40 ml) and water (40 ml) to afford pure 5 as a grey solid. Yield = 950 mg (76 %). 1 H NMR (500 MHz, CDCl 3 ): 7.99 (d, J = 8Hz, 12H), 7.49 (d, J = 8Hz, 12H), 7.24 (d, J = 8Hz, 12H), 7.00 (d, J = 8Hz, 12H), 3.91 (s, 18H). S5
Figure S4. 1 H NMR spectrum of compound 5 in CDCl 3 (500 MHz). Synthesis of 6. An amount of 950 mg (0.9 mmol) of compound 5, 10 ml NaOH 5 N, 11 ml THF and 11 ml MeOH were mixed in a 50 ml round bottom flask equipped with a magnetic stirring bar, and the mixture was refluxed for 16 h. The mixture was evaporated under vacuum and the residue was acidified with 3 M HCl. The grey solid was collected by filtration, washed with water and dried in an oven overnight. Yield = 889 mg (99 %). 1 H NMR (500 MHz, DMSO-d 6 ): 12.87 (br.s 6H), 7.13 (d, J = 8Hz, 12H), 7.32 (d, J = 8Hz, 12H), 7.53 (d, J = 8Hz, 12H), 7.81 (d, J = 8Hz, 12H). 13 C NMR (DMSO-d 6 ): 126.2, 127.2, 130.4, 130.8, 132.9, 136.6, 140.9, 141.2, 144.2, 168.0. SSI-MS m/z [M-H] - : 1254.1. S6
Figure S5. 1 H NMR spectrum of compound 6 in DMSO-d 6 (500 MHz). Synthesis of pbz-mof-1 A solution of 3 ml DMF, 1 ml acetic acid, 6 mg of H 6 L and 8 mg of ZrCl 4 was placed in a 20 ml glass scintillation vial. The vial was sealed and placed in an isothermal oven at 120 C for 36 hours. During this period, large colorless octahedral crystals of pbz-mof-1 were formed (see optical images below). Elemental analysis: C%: 46.06 (theo: 50.03), H%: 3.5 (theo: 3.04). C 94 H 68 O 32 Zr 6 Successful activation of the pbz-mof-1 was achieved by performing a straightforward activation procedure, using first acetone as a volatile solvent to remove the original guest molecules then followed by overnight drying under vacuum at room temperature. S7
Figure S6. Optical images of pbz-mof-1 single crystals. Single crystal X-ray crystallography The first solution of pbz-mof-1 crystal structure suggests a 6 connected Zr-hexanuclear cluster [Zr 6 (μ 3 -Ο) 6 (μ 3 -ΟΗ) 2 (O 2 C ) 6 (OH) 6 (H 2 O) 6 ]. Newertheless, 1H solid state NMR revealed presence of 5 acetate anions per cluster in the crystal. Two electron density peaks of 0.80 and 0.79 ē Å -3 were found in the expected positions and assigned as acetate carbon atoms. The atoms were refined with fixed occupancy (5/6) and bond distance was restrained to 1.50(1) Å. Finally, the pbz-mof-1 formula was assumed as [Zr 6 (μ 3 -Ο) 6 (μ 3 -ΟΗ) 2 (O 2 C ) 6 (Ac) 5 (OH)(H 2 O)]. H- atoms at the cluster (one H 2 O and three OH) were not localized but the reported formula includes them. Thermal parameters of acetate atoms O4, C11 and C12 were restrained to be the same with the standard deviation 0.01. Zr O2 distances were constrained to be the same with strong standard deviation 0.001 since they are chemically equivalent. U ij components of atoms O1 and C1 along O1 C1 bond were restrained to be the same with the standard deviation 0.01.Geometry of the benzene rings was constrained by set of DFIX, SADI and FLAT commands with strong standard deviation 0.001. ISOR 0.004 and ISOR 0.02 commands were used to made anisotrpoic thermal parameters of O3 and C10, respectively, reasonable. Thermal parameters of carbon atoms C3 and C4 were restrained to be the same with the standard deviation 0.01. Strongly delocalized electron density was found in voids and ommited from the refinement using the PLATON's SQUEEZE procedure. The pore volume equals to 63284.0 Å 3 (70.1% of the unit cell volume). S8
Table S1: Crystal data and structure refinement of pbz-mof-1. Identification code pbz-mof-1 Empirical formula C 94 H 68 O 32 Zr 6 Formula weight 2256.80 Crystal system, space group Unit cell dimensions Cubic, Fd-3m a = 44.856(2) Å Volume 90252(9) Å 3 Z, calculated density 16, 0.664 Mg m -3 F(000) 18048 Temperature (K) 100.0(1) Radiation type Cu K Absorption coefficient 2.48 mm -1 Absorption correction Multi-scan Max and min transmission 0.265 and 0.171 Crystal size Shape, color θ range for data collection 4.3 56.0 0.06 0.06 0.08 mm Octahedron, colorless Limiting indices -33 h 47, -36 k 48, -48 l 48 Reflection collected / unique / observed with I > 2 (I) Completeness to max = 56.0 99.1 % 30106 / 2761 (R int = 0.079) / 1755 Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 2761 / 47 / 112 Final R indices [I > 2 (I)] R 1 = 0.080, wr 2 = 0.248 Final R indices (all data) R 1 = 0.101, wr 2 = 0.270 Weighting scheme [ 2 (F o 2 ) + (0.2P) 2 ] -1* Goodness-of-fit 1.00 Largest diff. peak and hole 1.20 and -0.53 e Å -3 * P = (F o 2 + 2F c 2 )/3 CCDC number: 1497835 S9
Powder X-ray Diffraction (PXRD) Patterns: Figure S7. Powder X-ray diffraction pattern of the as-made pbz-mof-1 (blue line), acetone exchanged sample (green line), evacuated solid (orange line) and the corresponding pattern calculated from the single crystal structure (red line). Thermal Gravimetric Measurements (TGA): Figure S8. TGA curve for the as-made pbz-mof-1 and the corresponding exchanged solid, recorded under nitrogen flow with a heating rate of 5 deg/min. S10
Structural Figures Figure S9. The dihedral angles between adjacent phenyl rings in the hypotherical structure of polybenzene (a) and those found in pbz-mof-1 (b). In the later, for clarity purposes, the Zr-core atoms are shown in line representation, while the hexatopic linker and the carboxylates coordinated to the Zr-clusters, are shown in ball and stick. The small hexagon is defined by the carbon atoms of the coordinated carboxylate groups. Figure S10. Description of window and tetrahedral cage size found in pbz-mof-1. S11
Figure S11. Representation of the triangle widow found in pbz-mof-1. S12
NMR measurements of acid-digested sample Figure S12. 1 H NMR spectrum of evacuated pbz-mof-1 after digesting the sample in NaOH, DCl/DMSO-d 6 solution (600 MHz). S13
Additional CH 4 sorption data Figure S13. CH 4 sorption isotherm of pbz-mof-1, recorded at 112 K. S14
Table S2. Comparison of pbz-mof-1 with selected MOFs in terms of surface area, pore size, total CH 4 uptake and working capacity between 5-35 bar and 5-80 bar at 298 K. BET area, m 2 g -1 Total uptake at 35 bar, cm 3 cm -3 Total uptake at 80 bar, cm 3 cm -3 Total uptake at 80 bar, g g -1 Working capacity at 35 bar, cm 3 cm -3 Working capacity at 80 bar, cm 3 cm -3 Working capacity at 80 bar, g g -1 Langmuir, Pore Material m 2 g -1 size, Å MOF-519 2400 2660 7.6 200 279 0.209 151 230 0.172 MOF-905 3490 3770 18 145 228 0.297 120 203 0.264 Al-soc-MOF-1 5585 6530 14.3 127 221 0.464 106 201 0.422 HKUST-1-1977 11 225 272 0.221 153 200 0.162 MOF-520 3290 3930 16.2x9.9 162 231 0.282 125 194 0.237 pbz-mof-1 2415 2556 13 140 210 0.227 110 180 0.195 PCN-14-2360 14.3 200 250 0.218 128 178 0.155 AX-21-4880 n/a 153 222 0.326 103 172 0.252 Ni-MOF-74-1438 13.6 230 267 0.16 115 152 0.091 Table S3. Total CH 4 uptake of representative MOFs at 35 and 65 bar and the corresponding adsorbed phase density data. % increase in adsorbed Gravimetric CH 4 Experimental Adsorbed phase Gravimetric CH 4 Adsorbed phase phase density, uptake at 65 bar pore volume, density at 65 bar uptake at 35 bar, density at 35 bar between 35 Material g g -1 cm 3 g -1 g cm -3 g g -1 g cm -3 and 65 bar Al-soc-MOF 0.420 2.300 0.183 0.258 0.112 62.8 NU-111 0.360 2.090 0.172 0.241 0.115 49.4 MOF-905 0.279 1.340 0.208 0.193 0.144 44.6 MOF-520 0.274 1.280 0.214 0.198 0.154 38.7 pbz-mof-1 0.210 1.000 0.210 0.152 0.152 38.3 NU-125 0.287 1.290 0.222 0.225 0.174 27.6 MOF-519 0.195 0.940 0.207 0.153 0.163 27.4 UTSA-20 0.181 0.660 0.274 0.145 0.220 24.8 HKUST-1 0.216 0.780 0.277 0.184 0.236 17.4 PCN-14 0.197 0.850 0.232 0.169 0.199 16.6 Ni-MOF-74 0.148 0.510 0.290 0.135 0.265 9.6 a The adsorbed phase density is defined as the gravimetric uptake divided by the pore volume. S15
Figure S14. Volumetric CH 4 working capacity, between 5-80 bar at 298 K, of pbz-mof-1 and representative, top performing MOFs (see also Table S2). Figure S15. Percent increase of adsorbed phase density for representative MOFs, based on the data shown in Table S3. S16