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1 Electronic Supplementary Information Fluorite isoreticular series of porous framework complexes with tetrahedral ligands: new opportunities for azolate PCPs Ishtvan Boldog, *a,b Konstantin Domasevitch, a Jana K. Maclaren, c Christian Heering, b Gamall Makhloufi b and Christoph Janiak *b a Inorganic Chemistry Department, Taras Shevchenko National University of Kyiv, Vladimirskaya Street 64, Kyiv b Institut für Anorganische Chemie und Strukturchemie, Universität Düsseldorf, Universitätsstr. 1, D Düsseldorf, Germany c Institut für Anorganische und Analytische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, D-79104, Freiburg i. Br., Germany p. 1

2 Contents Chemicals and materials used...3 Syntheses of the ligands...3 1,3,5,7-tetrakis-(4-tetrazol-5-ylphenyl)-adamantane trihydrate, Ad(TtH) 4 3H 2 O...3 1,3,5,7-tetrakis-(4-tetrazol-5-ylphenyl)-adamantane hydrate, Ad(PhTtH) 4 6.5H 2 O...5 1,3,5,7-tetrakis-(4-cyanophenyl)-adamantane, Ad(PhCN) ,3,5,7-tetrakis-(4-tetrazol-5-ylphenyl)-adamantane hydrate, Ad(PhTtH) 4 6.5H 2 O...6 Syntheses of coordination polymers...7 {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF, [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6 DMA 2H 2 O 4MeOH, [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, Single crystal XRD structure determination...11 Structure solution and refinement of {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF, Structure solution and refinement of [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6DMA 2H 2 O 4MeOH, Structure solution and refinement of [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, Porosity estimation based on crystallographic data...18 Analytical measurements...21 General information on methods and devices...21 PXRD...22 [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6 DMA 2H 2 O 4MeOH, 2 and a stability test...22 [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, TGA...25 Ad(TtH) 4 3H 2 O...25 Ad(PhTtH) 4 6.5H 2 O...26 [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6 DMA 2H 2 O 4MeOH, Sorption measurements on degassed samples of Attempted solvent exchange and IR spectroscopy monitoring...29 p. 2

3 Chemicals and materials The chemicals used for the synthesis of organic compounds were of reagent grade and used as delivered by commercial suppliers. CuCl 2 (Aldrich, 99%), CuCl 2 2H 2 O (Alfa Aesar, 99%), CdCl 2 (Aldrich, 99%), N,N-dimethylformamide (VWR, ACS), N,Ndimethylacetamide (Aldrich, p.a., 99.8% anhydrous) and methanol (Acros, spectroscopic grade), were used for crystallizations without additional purification (care was taken to minimize the contact of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA) and methanol (MeOH) with air). Syntheses of the ligands 1,3,5,7-tetrakis-(4-tetrazol-5-ylphenyl)-adamantane trihydrate, Ad(TtH) 4 3H 2 O Br Br 2, Cat: AlCl 3 S: Br 2, refl. Br Br Br AdBr 4 NaCN, hν N N N NH S: DMSO CN N N N NH HN N N N N N HN N NaN 3, Cat: ZnCl 2 S: DMF, reflux NC CN CN Ad(CN) 4 Ad(TtH) 4 SFig. 1. Synthesis of Ad(TtH) 4 starting from adamantane. To a mixture of 1,3,5,7-tetracyanoadamantane (8.6 g, 36.4 mmol) [1] and sodium azide (28.4 g, 437 mol) in 500 ml of DMF anhydrous ZnCl 2 (39.6g, 291 mmol) was added under stirring. The formed mixture was refluxed for 48 h maintaining anhydrous conditions. Then, 350 ml of DMF was evaporated under reduced pressure and the residue was poured in 800 ml of cold 10% HCl (caution (!): efficient fumehood is required due to evolution of highly toxic and volatile HN 3 ). After ageing for a few hours, the formed precipitate was filtered-off and dried on air. p. 3

4 The obtained 9.9 g of the slightly yellowish crude product was recrystallized from 30 ml of DMSO (the mother liquor was additionally treated with 10 volumes of water and the formed residue was subjected to a repeated recrystallization). The formed stable crystalline adduct Ad(TtH) 4 4DMSO was dissolved in 250 ml of diluted NaOH solution and the product was reprecipitated by addition of 50 ml of conc. HCl. The yield of the white flossy product after drying at r.t. in air until constant weight was 9.1 g (the relatively low achieved yield in the generally high yielding click chemistry cycloaddition is explained by impurity of the starting tetranitrile and losses during recrystallization). According to elemental analysis, the obtained product is a trihydrate, Ad(TetH) 4 3H 2 O (54 % yield), which is satisfactorily corresponds to the water content registered by TGA (see p. 25). 1 H NMR (DMSO-D 6, 400MHz): δ= (s, 12H); 13 C NMR (DMSO-d 6, 500MHz): δ= 42.1 (C Ad H 2 ), 34.3 (C Ad Tt); m.p.:, instant decomposition was observed at 269 C (20 K/min heating rate), IR (KBr): ν = 3421 (s), 3130 (m), 3011 (s, br), 2867 (s, br), 2729 (s, br), 2634 (s, br), 1633 (m), 1554 (s), 1456 (w), 1417 (w), 1358 (w), 1254 (s), 1204 (w), 1204 (w), 1108 (w), 1058 (s), 987 (w), 891 (w), 733 (w), 583 (w, br). Elemental analysis, calcd (%) for C 14 H 22 N 16 O 3 : C 36.36, H4.80, N 48.46, found: C 36.61, H5.12, N Note: The structure of the highly crystalline Ad(TtH) 4 4DMSO adduct was determined by single crystal XRD (cell parameters and symmetry: tetragonal, I4 1 /a, a = Å, c = (24) Å). p. 4

5 1,3,5,7-tetrakis-(4-tetrazol-5-ylphenyl)-adamantane hydrate, Ad(PhTtH) 4 6.5H 2 O I OOCCF 3 I, I OOCCF 2 3 I S: CHCl 3, r.t. I AdPh 4 I Ad(PhI) 4 CuCN, DMF N N N NH CN S:DMF, reflux N NH ZnCl 2, NaN 3 NC N N N N HN N S: DMF, reflux CN HN N N N CN Ad(PhCN) 4 Ad(PhTtH) 4 SFig. 2. Synthesis of Ad(PhTtH) 4 starting from tetraphenyladamantane 1,3,5,7-tetrakis-(4-cyanophenyl)-adamantane, Ad(PhCN)4 A mixture of 47.2 g (50 mmol) of 1,3,5,7-tetrakis-(4-iodophenyl)-adamantane [2], 21.5 g (240 mmol) of copper cyanide in 470 ml of anhydrous DMF distilled over CaH 2 was mildly refluxed with stirring in a 1L round bottom flask under argon for 7h. The formed copper iodide precipitate was removed by filtration after cooling the contents of the flask to r.t. The filtrate was concentrated to 200 ml under reduced pressure and poured while hot in 600 ml of water containing 30 ml of ethylenediamine. The formed precipitate was separated by filtration and washed by copious amount of water. It was redissolved in 200 ml of hot DMF and poured while hot in 600 ml of 10% HCl. The ensued precipitate was separated as described above, dried on air, dissolved in 100 ml of hot DMF and precipitated by addition of 100 ml of iproh. After cooling the mother liquour in the fridge (~4 C), the resulted precipitate was collected by filtration and dried at 80 C to give g (82%) of the product as a white powder. 1 H NMR (DMSO-d 6, 500MHz): δ= 2.12 (s, 12H); 7.80 (broad s, 16H). 13 C NMR (DMSO-d 6, 500MHz): δ= 44.5 (C Ad H 2 ), 109, 119, 127 (C Ar H), 132 (C Ar H), 154. m.p. (in open capillary): C with oxidation / decomposition. p. 5

6 FT-IR (neat) ν, cm -1 : (w, br), 2928 (w, sh), 2854 (w), 1645 (vs), 1496 (w), 1450 (m), 1418 (m), 1384(s, sh), 1253 (w), 1105 (m), 1060 (w), 1008 (m), 841 (m), 788 (w), 761 (s), 729(w), 678 (m), 662 (m). 1,3,5,7-tetrakis-(4-tetrazol-5-ylphenyl)-adamantane hydrate, Ad(PhTtH) 4 6.5H 2 O A mixture of Ad(PhCN) 4 (7.03 g, 13 mmol), sodium azide (8.45 g, 130 mmol) and anhydrous ZnCl 2 (10.61 g, 78 mmol) was mildly refluxed in 500 ml of DMF for 7 h under inert atmosphere and stirring. After cooling, the slightly yellow solution with minor amount of white precipitate was poured in 500 ml of cold (~0 C) 10% HCl under stirring. The formed precipitate collected by filtration after 1h of staying was washed by 2x50 ml of 10% HCl solution and 3x50 ml of distilled water. The crude product containing DMF as a primary impurity was suspended in 300 ml of H 2 O and concentrated ammonia was added dropwise to the stirred slurry heated at 60 C until formation of a clear solution. It was acidified by addition of small portions of 5% HCl solution until ph = 2. The formed precipitate was collected by filtration after cooling to r.t., washed by 5 50 ml of distilled water and dried at 80 C until constant weight to afford 9.25g of white powder. The actual water content immediately after drying is less then 2 molecules of water (see TGA), and accordingly the yield is more than 95% (as standing in air causes slow rehydration, the water content was ascribed using the elemental analysis data for a freshly precipitated and air dried sample). 1 H NMR (DMSO-d 6, 400MHz): δ= 8.05 (d, 8H, J = 8.4 Hz), 7.89 (d, 8H, J = 8.4 Hz), (s, 12H). m.p. (in open capillary): no melting, gradual decomposition starts at >250 C (20 K/min heating rate). FT-IR (neat) ν, cm -1 : (m, wb), 2933 (m), 2857 (m), 2740 (m), 1617 (s), 1565 (m), 1499 (s), 1434 (m), 1359 (m), 1247 (w), 1180 (w), 1155 (w), 1067 (m), 1025 (m), 996 (s), 896 (w), 840 (s), 785 (m), 751 (s), 727 (m), 703 (m), 574 (s). Elemental analysis on an freshly precipitated and air dried (r.t.) sample, calcd (%) for: C 38 H 45 N 16 O 6.5 : C 55.00, H 5.47, N 27.01, found: C 54.92, H 5.08, N p. 6

7 Syntheses of coordination polymers {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF, 1 Synthesis / crystallization 5.1 mg (30 µmol) of CuCl 2 2H 2 O and 5 mg (10 µmol) of Ad(TtH) 4 3H 2 O were dissolved in a mixture of 1.2 ml of DMF and 0.3 ml of MeOH and sealed hermetically in a 2ml screw capped glass vial. The formed solution was placed in an oven at 70 C, which resulted in rapid precipitation of a light blue crystalline deposit. After 2 days the temperature was raised to 100 C and the mixture was aged for at least 3 days. The crystals underwent a slow conversion to small cubic monocrystals of deeper blue colour (yield:< 2 mg) and to a second phase consisted of colourless Cu(I) species. Optimization study Only a partial conversion of the initial light blue precipitate to the product was reached under any attempted conditions (temperature, excess of copper chloride and water concentration were varied). Complete conversion under the described condition didn t occur completely even after 7 days of heating at 100 C. Longer heating times or, especially, use of higher temperatures, cause slow decolorization of the precipitate indicating the formation of Cu(I) species. If large excess of copper is used, a visibly less pure precipitate is formed and contamination by Cu 2 O was also observed (especially at temperatures higher than 100 C). Addition of small amounts of water (50µL to 1.5 ml of reaction mixture) seems to speed up the process, but decrease somewhat the quality of the crystals. The ratio of DMF:MeOH was subjected to optimization and the ratios 3:1-4:1 were found to be optimal for single crystal growth. p. 7

8 [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6 DMA 2H 2 O 4MeOH, 2 SFig. 3. Large scale preparation of 2 (left) and an image of the aggregated crystals (the largest globular aggregate is slightly more than 1mm in size). Solid CuCl 2 2H 2 O (460 mg, 2.7 mmol) and Ad(PhTtH) 4 6.5H 2 O (160 mg, mmol) were dissolved in 32ml of DMA inside a 50 ml glass vial. To the formed yellowish-brown solution 8 ml of MeOH was added, which caused an immediate formation of a light-green precipitate. The mixture was heated at 70 C for 10 days. Deposition of large green octahedral crystals started after a few hours and was accompanied by gradual dissolution of the initial precipitate and formation of white flocky precipitate as a byproduct. The crystals were separated shortly after the vial had been taken out from the oven. The supernatant with the flocky by-product was separated by repeated decantations using minimal amount of fresh DMA/MeOH (4:1) mixture. During filtration the product was double washed (2 3 ml) with the same solvent mixture and then quickly with MeOH (2x5 ml). After drying at RT under 5 Torr vacuum for few minutes, 242 mg of product was isolated (yield: 48%). The product has some solubility in pure DMA. All work-up operations were performed allowing minimal (< 1 min in total) air contact, and the obtained material was stored under argon. IR (neat): 2928(w). 2898(w), 2852(w), 1602(vs), 1501(m), 1456(s), 1418 (s), 1400 (s), 1357 (s), 1262(m), 1009 (s), 841 (m), 760 (s), 590 (m). Elemental analysis, calcd (%) for C 104 H 130 Cl 4 Cu 6 N 38 O 12 C 47.54, H 4.99, N 20.26; found C 47.68(47.32), H 5.02(5.16), N 20.57(20.57) (the numbers in the bracket correspond to a repeated assay). p. 8

9 Optimization study. A number of conditions (including temperature, concentration, addition of water, excess of copper chloride) were scanned in order to optimize the quality of the single crystals. In all cases the crystals tended to form large globular aggregates with small monocrystalline components, often with a rhomboid shape. Though the optimization experiments, didn t lead to dramatic improvement in quality of the crystals, it allowed to improve significantly the yield and obtain a quite phase pure sample. The reported large scale experiment yielded the best quality single crystals. It is worth to note the result of some optimization attempts. The use of excess of anhydrous CuCl 2 and DMF as a solvent yields a product with the same framework structure (confirmed by single crystal XRD). It is significantly darker compared to the product obtained starting from CuCl 2 2H 2 O in DMA/MeOH and consists of good quality cube crystals, but the yield is very small (144 mg with ~15% yield of product was obtained from 1130 mg of CuCl 2 and 600 mg of the ligand in 40ml of DMF). Curiously, if the product is left in the mother solution it slowly redissolves thus demonstrating a high reversibility of crystallization under these conditions and the importance of hydrated copper chloride use. Combined use of hydrated CuCl 2 2H 2 O and DMF / MeOH mixture allowed to increase the yield and the further change of DMF to DMA (which caused slight crystallization slow-down), allowed to improve slightly the size and quality of the crystals and achieve slightly better scalability. [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, 3 Crystallization: 18.3 mg of anhydrous CdCl 2 (0.1 mmol), 5 mg of Ad(PhTtH) 4 6.5H 2 O (3.2 µmol) and 1 ml of DMF were placed in a 2 ml vial and sealed with a Teflon-lined screw cap. The mixture was homogenized via prolonged shaking and heated at 70 C for 1 week. A few large transparent block crystals were formed along with some quantity of concomitant crystalline phase in a form of small elongated blocks (CdCl 2 2DMF; crystallography: monoclinic, C2/c, a = (5) Å, b = (5) Å, c = (2) Å, β = (10)) and amorphous impurities. Yield: <5 mg, the sample was used for the single crystal XRD analysis. The quality of crystals in the mother solution is retained at least during months, but additional precipitation of CdCl 2 2DMF were observed. Preparative: p. 9

10 770 mg (4.2 mmol) of CdCl 2 and 500 mg of Ad(PhTtH) 4 6.5H 2 O were dissolved in 3:1 mixture of DMF and MeOH and heated in a sealed tube for 5 days. The product was filtered avoiding prolonged air contact, washed 3 times with 10 ml of DMF and dried at 10-2 mbar. The yield of the dried product was 589 mg. Elemental analysis, calcd (%) for C 94 H 102 Cd 7.15 Cl 6.3 N 38 O 8 C 38.68, H 3.52, N ([Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] 6DMF 2H 2 O CdCl 2 ); found C 38.59, H 3.48, N: The ascribed formula of the compound is [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv (Solv = ~4-6 DMF 2H 2 O nmeoh, where n = 0 in the case of crystallization from DMF and n ~ 4 in the case of crystallization from MeOH. The numbers are approximate and given in analogy with the data for 2, which was obtained in a phase pure form) Optimization study. The use of anhydrous CdCl 2 in DMF/MeOH 3:1 mixture is superior in terms of yield and product purity (though the product is still a mixture). The presence of minute amounts of water could be regarded important as in the copper analogue, though the use of CdCl 2 5/2H 2 O was not productive as it has low solubility in DMF. Its preparation in situ (dissolution of anhydrous CdCl 2 followed by addition of H 2 O (~10% mol excess)) decreased the amount of byproducts, but affected negatively the crystallinity. A small amount of water might be essential for the formation of the product, but its excess might lead to partial substitution of the weakly coordinated DMF molecules and, seemingly, to decrease of crystallinity. p. 10

11 Single crystal XRD structure determination A common feature of all crystalline samples is twinning of optically acceptable monocrystals, which correlates with near-merohedral twinning opportunities provided by high crystallographic symmetry. The crystallinity of large specimen was generally low as evidenced also by powder XRD patterns (see below). The crystals were measured in oil or in a drop of epoxid glue. Particular details concerning the instrument and experimental details are given in the compound-specific sections below. The structures were solved using SIR-92 [3] or SHELXS-97 [4] programs and refined using SHELXL-97 [5]. The crystal data and refinement details are summarized in STab. 1. In the case of 1 solvent molecules were modeled, but for 2, 3 they were excluded by SQUEEZE [6] (PLATON [7]) procedure with the exception of the immediately coordinated oxygen atoms. The hydrogen atoms, if other information is not given below, were placed geometrically and refined using a riding model with the U iso isotropic thermal displacement parameter set equal to 1.2 U eq, where U eq is the thermal displacement parameter of the parent heavy atom. p. 11

12 Structure solution and refinement of {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF, 1 SFig. 4. An octahedral crystal of {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF, 1 used for single crystal XRD experiment. The compound crystallizes in a form of small deep blue blocks, with most symmetric ones having an octahedral habitus. The crystals were generally of low quality (a probable result of slow conversion of the light blue phase to the final deep blue one, an obviously non-uniform growth process). The selected crystal was measured on a Super Nova diffractometer from Oxford Diffraction equipped with an Atlas CCD detector using copper X-ray microfocused source. SFig. 5. An ORTEP style representation (50% probability elipsoids) of the asymetric unit of {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF, 1 with atom numbering. The bonds to symmetry equivalents and their designations are given in gray. p. 12

13 Automated space group determination (XPREP [8]) suggested Fm 3m space group, high symmetry of which implied structural disorder with a high probability. Accordingly, the structure was solved and refined both in Fm 3m and C2/m groups in order to eliminate the possibility of structural information loss due to enforcement of higher symmetry. Both solutions contained essentially the same disorder and the lower symmetry solution didn t provide any additional information concerning the disordered components in the voids. The refined structure manifests a disorder of copper as well as of nitrogen atoms belonging to the tetrazolate moieties (the thermal displacement parameters were isotropically restrained for the N2 atom). The scheme of the disorder is shown on SFig. 5, SFig. 6 and a representative fragment of the framework with non-disordered (reduced) SBUs is shown on SFig. 7 (the disorder on the level of SBU doesn t alter the bonding directions towards its neighbours and hence the overall connectivity). Refinement with unrestrained occupation factors gave absolute occupancy for Cu1 (0.661 relative occupancy at 24e Wickoff position), for N1 (0.587 at 96k), for N2 (0.603 at 96k) and (0.724 at 24e). The values found correspond very well to the triple disorder model prescribing 2/3 disorder occupancy factors for a [Cu 4 Cl(AdTt 4 ) 2 ] - single charged anionic moiety. An important question, not entirely clarified by the crystallographic data is the nature of the charge compensating cation for the charged framework structure. Unfortunately it was not possible to locate the position of the cation, which is seemingly disordered in the center of the cavity. Instead a simplified structural model was used accordingly to which one Cu 2+ cation per two [Cu 4 Cl(AdTt 4 ) 2 ] - is disordered on the same positions as the other copper atoms, which increases the previously given disorder occupation factor from 2/3 to 3/4. The occupancy factors of the copper atom and the DMF molecule coordinated to it was fixed in accordance with the latter value during subsequent refinement. Accordingly, the simplified formula was postulated to be {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF as a special case of [Cu 4 Cl(AdTt 4 ) 2 (DMF) 4 ] (Cation) Solv general formula. It is necessary to stress that the postulated formula is only a simplification. Its realization is highly improbable as as an additional copper atoms would disrupt the stable [Cu 4 (Tetrazolate) 8 ] double-crown arrangement. The hydrogen atom of the adamantane moiety was refined with a distance restraint (d(c-h) = 0.96 Å). p. 13

14 SFig. 6. The {Cu 4 (µ 4 -Cl)(tetrazolate) 8 } coordination bonded cluster serving the role of 8- connected secondary building unit (SBU) in 1. (a) The representation of the actual structural disorder. Four copper atoms are disordered over six vertices of the light-blue octahedron, which symbolizes the three orthogonally intersecting {Cu 4 } planes of non-disordered components, shown on (b) and (c) The tetrazolate groups are disordered over three positions, which are depicted as capped blue prisms with vertices corresponding to partially occupied positions. (b), (c) a non-disordered SBU. The coordinated solvent molecules are not shown for clarity. SFig. 7. The framework structure of 1 (a) and metrically faithful representation of the fluorite underlying net (b). The oxygen molecules on (a) corresponds to coordinated DMF molecules (are not shown for clarity). The disordered {Cu 4 (µ 4 -Cl)} cluster is reduced to one component and on (b) figure the cluster is symbolically represented by a {Cu} 4 square. p. 14

15 Structure solution and refinement of [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6 DMA 2H 2 O 4MeOH, 2 SFig. 8. An ORTEP style representation (50% probability elipsoids) of the asymetric unit of [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6 DMA 2H 2 O 4MeOH, 2 with atom numbering. The bonds to symmetry equivalents and their designations are given in gray. Crystals of 2 demonstrated a tendency towards quality deterioration with time even if stored under mother liquor. A number of crystals (mounted in a drop of perfluorinated oil) were tested until a satisfactory specimen was found as most of the optically suitable specimens were of poor crystallinity. The measurement was performed on a Bruker Apex2 diffractometer with a microfocused Mo source and equipped with an area detector. A temperature scan aiming optimal diffraction experiment was also performed. At a temperature slightly below 220K a possible phase-transition was detected. The experiment was performed at 220K (a = , b = , c = cell dimensions, Å) and 100K (a = , b = , c = ) with better result in the second case. Interestingly, a similar behaviour was found for the cadmium analog 3, but in the latter case higher temperatures assured dramatically better diffraction quality. The main complication of the structure refinement was the treatment of the disordered external copper and chloride atoms (Cu2 and Cl2, see atom numbering scheme on SFig. 8) as the structure allows variable amounts of them. Refinement with unrestrained site occupation factors (SOFs) were used to access the composition. For 'Cu2' and 'Cl2' atoms , SOF values were found, which were rounded in subsequent refinement to and , corresponding to a Cu 2 Cl 3 supplement in the p. 15

16 [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] Solv formula, ensuring also the electroneutrality of the latter. Concerning the nature of the solvent molecules and their quantity, the structural data provides only rather limited information (the final composition was determined with a help of TGA and elemental analysis). As it is known that DMF is a more potent ligand compared to water [9] under comparable synthetic conditions, the O1 O2 atoms should belong mainly to DMA (4 per formula unit), but appreciable site sharing with water or MeOH is not excluded either. The SOFs of the latter two atoms were set equal to the value of their parent metal atom to maintain a consistent model. The hydrogen atoms were placed geometrically and refined using a riding model. SFig. 9. The {Cu 4 (µ 4 -Cl)(Tt) 8 ) Cu 2 Cl 3 (O Solv ) 4 } SBU representing the eight-connected node of the fluorite net. A top view (a) and an partial side view (b) are given for clarity. The disordered components are semitransparent (faded colours) and the atom numbering scheme is shown in gray. The connections of the {Cu 4 (µ 4 -Cl)} unit with the disordered part are given in thinner dashed lines. The oxygen atoms belong to coordinated DMA molecules. p. 16

17 SFig. 10. a The framework structure of 2 with the cell edges given in orange. The disordered components are not shown for clarity. b The underlying fluorite net of 2 with cubic and tetrahedral nodes corresponding to the coordination bonded SBU and the ligand respectively (given in blue and orange). Structure solution and refinement of [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, 3 SFig. 11. An ORTEP style representation (50% probability ellipsoids) of the asymetric unit of [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, 3 with atom numbering. The bonds to symmetry equivalents and their designations are given in gray. The crystals of 3 demonstrated better diffraction at comparable size compared to 2 copper analog, also retaining good quality in mother liquor during at least 3 months p. 17

18 after the synthesis. A relatively large crystal (0.080 mm x mm x 0.210) of a rhomboid form was measured using an Bruker Apex Quazar diffractometer. Measumerents were carried out at 220K and 100K, but only the higher temperature measurement was of satisfactory quality. Interestingly, the diffraction quality decrease upon cooling is reversible. Such behaviour suggests a possibly incomplete low temperature phase transition, which seemingly also takes place in the case of 2. The refinement was performed analogously to those described for the copper analog, 2. The SOF-unrestrained refinement gave the occupancies for Cd2 and Cl2 atoms at and The values were fixed at and respectively, which correspond to Cd 2 Cl 3 supplement to the [Cd 4 (µ 4 -Cl)L 2 ] core formula, ensuing overall electroneutrality. In both cases the SOF-unconstrained refinement gives consistent results, which supports the verity of the chosen model. It is also interesting to compare the electronic counts given by the SQUEEZE procedure for the isostructural compounds 2 and 3 at 1602 and 1069 per formula unit respectively. The found absolute values are physically non reasonable (the electron count of a DMF or DMA molecule refers to the range of giving an impossible estimate of molecules per formula unit), which could be explained by disorder. On the same time the ratio is of the two numbers obtained for the two isostructural compounds seemingly reflects correctly the different density of guests in the voids. The use of a DMA/MeOH solvent mixture at the synthesis of 2 allows the incorporation of smaller MeOH molecules assuring denser packing in comparison with 3, the sample of which was synthesized from a DMF solution without co-solvent. Porosity estimation based on crystallographic data The volume of solvent accessible voids were computed by CALC SOLV (Platon) procedure [7]. It was applied to a reduced structural input consists of {[M 4 L 2 ]} framework based on an idealized SBU shown on SFig. 12. The disorder of the ligand or metal atoms were reduced to one component for correct interpretation by the CALC SOLV procedure. As the disorder of the ligand in 1 is inherent in Fm 3 m symmetry, the input model in this case was given in C2/m symmetry. The central chloride ion was also removed to fulfill the electroneutrality condition. The {[M 4 L 2 ]} minimalistic framework could indeed be obtained by solvent exchange and degassing as it was shown for the case of H 4 L = 1,3,5,7-tetrakistetrazol-5- ylmethane [13]. Thus the reported numbers assess the maximal possible porosity for the reported compounds. The next values for the relative volume of solvent accessible voids were found: - 1: 57.0% (calc. in C2/m symmetry). - 2: 77.0% - 3: 77.3% p. 18

19 SFig. 12. The minimal {M 4 (Tetrazolate) 8 } SBU sustaining the idealized [M 4 L 2 ] frameworks. p. 19

20 STab. 1 Crystal data and structure refinement for {[Cu 4 (µ 4 -Cl)(Ad(Tt) 4 ) 2 ] 2 Cu} 9DMF, 1; [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6DMA 2H 2 O 4MeOH, 2; [Cd 4 (µ 4 - Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, Empirical formula C 83 H 111 Cl 2 Cu 9 N 73 O 9 C 76 H 56 Cl 4 Cu 6 N 32 Solv C 76 H 56 Cd 6 Cl 4 N 32 Solv FW /g mol T /K (2) 220(2) Wavelength / Å Crystal system Cubic Tetragonal Tetragonal Space group Fm 3 m I4/mmm I4/mmm a /Å (19) (3) (5) b /Å (19) (3) (5) c /Å (19) (12) (7) α, β, γ / V /Å (11) (5) (5) Z Calc. density / g cm µ / mm F(000) Crystal size / mm x 0.09 x θ range / 4.11 to to to Index ranges / hkl [-22;23], [-19;23], [23;20] [-23;23], [-21;23], [-38;39] [-19;23], [-19;23], [-37;30] Reflections collected Independent reflections 391 [R(int) = ] 3259 [R int = ] 3094 [R(int) = ] Completeness /%, θ max / 98.5 %, , , Max. and min. transmission and and and Refinement method Data / restraints / parameters Full-matrix least-squares on F 2 Full-matrix least-squares on F 2 Full-matrix least-squares on F / 8 / / 12 / / 0 / 111 Goodness-of-fit on F Final R indices [I>2σ(I)] R1 = , wr2 = R1 = , wr2 = R1 = , wr2 = R indices (all data) R1 = , wr2 = R1 = , wr2 = R1 = , wr2 = Largest diff. peak and hole, e Å -3 Electron count in the voids per cell (by SQUEEZE) and e.å and e.å and e.å * 2138* * - the electron count doesn t include a small accounted part associated with the oxygen atoms of the coordinated solvent molecules (4 per formula unit in 2 and 6 per formula unit in 3). p. 20

21 Analytical measurements General information on methods and devices 1 H and 13 C spectra were recorded on Bruker Avance DRX-200 and Bruker Avance DRX-500 instruments respectively. FT-IR spectra were recorded using a Bruker Tensor 37 system equipped with an ATR unit (Platinum ATR-QL, Diamond) in the cm -1 region with 2 cm -1 resolution. The PXRD measurements were performed on a finely ground sample equally distributed on a low background silicon sampleholder by a Bruker AXS D2 PHASER instrument equipped with a Lynxeye 1D detector and using Ni-filtered copper Kα radiation (30kV, 10mA generator parameters; restricted by a 0.6 mm divergence slit and a 1 Soller collimator) at 0.02 measurement step width. The simulated PXRD patterns were generated using Mercury 2.3 program [10], with 0.02 step and FWHM(2θ) = 0.1 further scaled by an adapting exponential function aiming better correspondence to the experimental data. Hydrogen and nitrogen absorption / desorption isotherms were measured at 77K using a Micromeritics ASAP 2020 automatic gas sorption analyzer. Ultra high purity (UHP, grade 5.0, %) nitrogen and helium gases were used (the former for cold and warm free space correction measurements). The thermogravimetric (TG-DTA) analyses were performed on a Netzsch STA 449 C Jupiter instrument coupled with a Pfeiffer Thermostar GSD 300 mass spectrometer at 10 C/min heating rate in a protecting flow of nitrogen using corundum sample holders. p. 21

22 PXRD [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6DMA 2H 2 O 4MeOH, 2 and a stability test SFig. 13. Comparison of experimental and simulated PXRD pattern for 2. The simulated pattern is scaled by an exponential function in order to show better the high-angle peaks of low intensity. Distinct line broadening and large amorphous area observed on the PXRD spectrum witnesses the relatively low crystallinity of 2, which is at least partially could be explained by decrease of structural integrity even under mild evacuation at app. 5 Torr and room temperature. In the same time some relative peak intensities are retained at 2θ = 40, which indicates partially preserved long-rang order. The line broadening could be interpreted, at least partially, as caused by strong mosaicing rather then by complete structural collapse. Despite the loss of fine pattern details there is an exact correspondence between the experimental and simulated spectra with the exception of two lines (at ~9 and 11 ), which are masked by broad adjacent peaks. A simple stability test was also performed. A freshly isolated sample was measured after 4h of initial short contact with air and then repeatedly after ~20h of staying in air. No significant changes are visible on background corrected samples, except that of the relative intensity of the large peak s shoulder at ~6. Though the amorphous region on the uncorrected spectra did somewhat differ, the difference was not p. 22

23 exactly quantifiable without more precise experiments. Seemingly there was some quality deterioration, but it is not significant during less then 1 day of observation. SFig. 14. Stability-on-air test for 2. The patterns are baseline corrected and smoothed. p. 23

24 [Cd 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cd 2 Cl 3 ] Solv, 3 SFig. 15. Comparison of experimental and simulated PXRD pattern for 3 (with CdCl 2 2DMF as one of the identified impurities). The experimental pattern is smoothed and partially baseline corrected, while the simulated pattern is scaled by an exponential function in order to show better the high-angle peaks of low intensity. The PXRD pattern (SFig. 15) witnesses that though 3 is the major product, the mixture contains other crystalline phases as well. At least one of them (CdCl 2 2DMF) was identified by single crystal XRD analysis (see the cell parameters on p. 9). Interestingly, the peak broadening is less in the case of 3 compared to its copper analog, 2, which might suggest higher overall crystallinity. p. 24

25 TGA Ad(TtH) 4 3H 2 O SFig. 16. TG-DTA curves for Ad(TtH) 4 3H 2 O. Ad(TtH) 4 3H 2 O loses water in two steps: the first step finishes near 100 C and corresponds to a loss of approx. 1 molecule of water (SFig. 16.). Further dehydration starts only at temperatures exceeding 150 C indicating strong binding of residual water to tetrazole groups. The process finishes abruptly at approx. 180 C indicating a loss of 11.5%, which correspond to 2.96 molecules of water. The abrupt finish of the dehydration accompanied by a considerable endothermic effect suggests a possible structure transformation. After ~220 C a progressing decomposition of the ligand starts. The measurement was finished before 250 C as an instrument-protective measure since an attempted melting point determination demonstrated a rapid, almost explosive decomposition at 269 C. p. 25

26 Ad(PhTtH) 4 6.5H 2 O SFig. 17. TG-DTA curves for Ad(PhTtH) 4 6.5H 2 O Ad(PhTtH) 4 is practically dehydrated at ~140 C (SFig. 17), thus demonstrating an expectedly less hydrophilicity compared to Ad(TtH) % weight loss corresponds to 3.5 molecules of water of crystallization. The obtained value somewhat contradicts with the elemental analysis, which gave 6.5 molecules. The probable reason of discrepancy is the relatively prolonged (30 min) additional drying of the compound in the TGA measurement chamber in a flow of inert gas. It is clearly visible that a part of the water is already lost at temperatures below 50 C, when the second dehydration stage starts. Complete dehydration take place at approximately 160 C, indicating strong binding of water and presumably slow re-hydration in air. Gradual decomposition of the substance starts at app. 220 C. As no explosive conversion were registered during the attempted m.p. determination, which demonstrated a protracted decomposition starting at > ~250 C (20K / min heating rate), the TGA experiment were done until complete decomposition at app. 650 C. The first decomposition wave (~220 C 300 C) corresponds to a weight loss of 21.3% or ~12 nitrogen atoms. The carbonification is not complete and continues further, accompanied with pyrolysis and sublimation of unidentified products. p. 26

27 [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] 6DMA 2H 2 O 4MeOH, 2 SFig. 18. TG-DTA curves for 2 (the bottom image generated by the instrument s software contains some additional information). The TGA experiment on 2 is given on SFig. 18. The first, well separated weight-loss stage (<100 C, 10%) is associated mainly with the removal of MeOH and p. 27

28 partially water. The subsequent stage (~100 - ~200 C, 17.4%) is associated mainly with the loss of DMA, which continues slightly further, but partially overlaps with the ongoing exothermic steps of ligand s decomposition (peaking at 224 C and 334 C), which finishes at app. 370 C. Ascribing the [Cu 4 (µ 4 -Cl)(Ad(PhTt) 4 ) 2 Cu 2 Cl 3 ] formula to the residue at 200 C it is possible to estimate roughly the content of methanol ( 8 molecules) and DMA (< 6 molecules). A second TGA experiment was done for a sample dried overnight at 10-2 Torr. The comparison of two experiments (SFig. 19) allows to conclude that the overnight evacuation removes most of methanol leaving the DMA practically intact. The difference between the curves in the interval of C suggests a presence of small amount of water. However, reasonable estimation of water from TGA data is not feasible. The assignment of the final formula was done as a compromise between TGA and elemental analysis data with the latter also suggesting a presence of a minute amount of water. SFig. 19. Comparison of TGA curves for a freshly prepared 2 (red) and a sample after drying at 10-2 Torr, r.t. (black). p. 28

29 Sorption measurements on degassed samples of 2 All sorption experiments except one case of hydrogen sorption by a partially degassed sample demonstrated no significant gas adsorption (i.e. sorption capacities typical for a non-porous material were found). Low stability of framework against structural collapse was observed, which doesn t preclude the possibility of successful structure-preserving degassing methods more mild than described below (e.g. by supercritical drying). It is also possible that the removal of the external CuCl 2 during attempted solvent exchange experiments is a contributing factor, which decreases the stability of the framework to the extent that its stability is challenged even by presence of such mild ligands as methanol or water. Attempted solvent exchange and IR spectroscopy monitoring Solvent exchange was attempted by Soxhlet extraction of 2 by MeOH (spectroscopic grade) during 5 days. The process was performed under nitrogen and the average temperature of the contacting phases was around ~50 ). Comparative IR spectra of the obtained sample, as-synthesized and dried in air are shown on SFig. 20. The MeOH exchanged sample demonstrated a strong decrease of band intensities associated with DMA (see also SFig. 21 for comparison), but there is a small residual peak at 1618 cm -1 as well as faint residual peaks at 1263 cm -1 and 1188 cm -1, i.e. the exchange was not truly complete. The reached degree of solvent exchange is obviously high, but it is hard to quantify it due to possible peak overlap. The larger residual peaks at 1618 cm -1 and 1008 cm -1 could be partially attributed to tetrazolate complexes in general [11]. For example, the published IR spectrum for Cu(5-PhTet) 2 H 2 O [12] contains medium strong bands at 1650, 1623 and 1014 cm -1. Presence of medium strong bands at 1614 cm -1 and 1008 cm -1 were reported for Cu(ttpm) 2 0.7CuCl 2 (H 4 ttpm = tetrakis-(5- phenyltetrazolyl)methane) analogue complex to 2, obtained by removal of DMF from the structure [13] (though, the removal might have been not complete either). Interestingly, long air drying also caused significant decrease of DMA content. In this regard air-drying was next only technique to the extraction with methanol and better than a single soaking in THF or CH 2 Cl 2. Though, in all the described cases the crystallinity was not retained according to PXRD. In the case of Soxhlet extraction the the shape of the crystals remained externally intact, but their optical quality significantly decreased either. p. 29

30 SFig. 20. IR spectra of the freshly prepared 2 (green), the same material subjected to air drying during two weeks (black) and MeOH exchange by Soxhlet extraction during 5 days (red). SFig. 21. IR spectra of DMA and methanol given for comparison with the spectra of the solvent exchanged material. p. 30

31 SFig. 22. IR spectra of the sample extracted by MeOH prior degassing and after the adsorption experiment. No visible chages, except the decrease of the peak at 1008 cm -1 partially attributed to the strongest band in the spectrum of MeOH (the remaining peak is attributed to DMA, which is responsible for some absorbance in this region either ). Very mild degassing conditions (30 C, 10-8 Torr vacuum) of the methanol exchanged sample were enough to remove not only the more volatile methanol, but even decrease the amount of the residual DMA to some extent (SFig. 22). Though, the degassed sample demonstrated practically no sorption, which is in accordance with its low crystallinity. Other solvent exchange attempts (soaking in MeOH, THF, CH 2 Cl 2 at room temperature) were not successful as well. Measurable sorption capacities were achieved only with an as synthesized sample and only with hydrogen, obviously because the porosity achieved by partial degassing was not enough to allow an effective passage of larger molecules. H 2 sorption measurements An as synthesized sample of 2 was degassed at 60 C (until < 1µTorr / min pressure rise rate) in 10-8 Torr vacuum (during repeated experiments degassing at 100 C didn t provide advantages, while the use of temperatures higher than 100 C caused decreasing of sorption capacity accompanied with colour change of the sample to dirty brown, probably indicating rather decomposition than mere desolvation). The hydrogen sorption isotherm is shown on SFig. 23. The amount of adsorbed hydrogen at 1 bar and 77K is small (~52 ml for a 53.4 mg sample, 0.46 wt%) in accordance with pores, partially occupied with DMA molecules. A well defined p. 31

32 hysteresis, not usual for sorption of hydrogen, is present and could be explained by very narrow pores (and consequently kinetic trapping [14, 15]) and gate effects in the partially evacuated sample. The effect is probably analogous in nature, albeit less pronounced, to kinetic trapping in narrow pores. SFig. 23. Sorption of hydrogen (left) and nitrogen (right) in the degassed sample of 2a. The adsorption of nitrogen is so low that the error in void volume estimation causes the effect of seemingly negative adsorption. p. 32

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