Supporting Information

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1 Supporting Information Wiley-VCH Weinheim, Germany Pd Uptake and H 2 S Sensing by an Amphoteric Metal Organic Framework with a Soft Core and Rigid Side Arms** Jieshun Cui, Yan-Lung Wong, Matthias Zeller, Allen D. Hunter, and Zhengtao Xu* anie_ _sm_miscellaneous_information.pdf

2 Supporting information General Procedure. Starting materials, reagents, and solvents were purchased from commercial sources (Aldrich, Merck and Acros) and used without further purification. Elemental analysis was performed with a Vario Micro CUBE CHN elemental analyzer. FT-IR spectra were obtained using a Nicolet Avatar 360 FT-IR spectrophotometer. The ratios of the metal ions were determined by using a PerkinElmer Optima 2100 DV ICP optical emission spectrometer. Scanning electron microscope (SEM) was collected using Philips XL30 ESEM. Powder X- ray diffraction data for the BFMOF-1 related samples were collected in the reflection mode at room temperature on an Inel Equinox 1000 X-ray diffractometer (Inel, France) equipped with CPS 180 detector using monochromated Cu-Kα1 (λ = Å) radiation. The X-ray tube operated at a voltage of 30 kv and a current of 30 ma. Single crystal diffraction data were collected on a Bruker APEX II CCD diffractometer at 100 K using monochromatic Mo-K radiation with the omega scan technique. Data for BFMOF-1-DMF, BFMOF-1, and BFMOF-1a were collected, their unit cells determined, and the data integrated and corrected for absorption and other systematic errors using the Apex2 suite of programs. [1] The space group was assigned and the structure was solved by direct methods using the SHELXTL suite of programs [2] and refined by full matrix least squares against F 2 with all reflections using Shelxl2013. [3] H atoms attached to carbon and nitrogen atoms were positioned geometrically and constrained to ride on S1

3 their parent atoms, with carbon hydrogen bond distances of 0.95 Å for aromatic C-H, 0.99 and 0.98 Å for aliphatic CH 2 and CH 3, respectively. Methyl H atoms were allowed to rotate but not to tip to best fit the experimental electron density. U iso (H) values were set to a multiple of U eq (C) with 1.5 for CH 3 and 1.2 for C-H and CH 2 units, respectively. Complete crystallographic data, in CIF format, have been deposited with the Cambridge Crystallographic Data Centre. CCDC contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via For details on the individual structures, see the Single Crystal X-ray Crystallography section of this document. Solution 1 H and 13 C NMR spectra were recorded on a 400 MHz Bruker superconducting magnet high-field NMR spectrometer at room temperature, with tetramethylsilane (TMS) as the internal standard. Thermogravimetric analyses (TG) were carried out in a nitrogen stream using PerkinElmer Thermal analysis equipment (STA 6000) with a heating rate of 5 C/min. The porosity and surface area analysis was performed using a Quantachrome Autosorb iq gas sorption analyzer. Each sample was outgassed at 0.03 torr with a 2 C/min ramp to 110 C and held at 110 C for 12 hours. The sample was then held at vacuum until the analysis was run. CO 2 adsorption/desorption isotherms at 273 K were performed on a Quantachrome Autosorb 1MP instrument. Initial data analysis was done using the AS1Win and QuadraWin 5.05 software (both of Quantachrome instruments). NLDFT analysis of the CO 2 adsorption isotherm (273 K) was done using a commercialized model (assuming carbon-co 2 interaction parameters and slitpore morphology). High purity gases were used throughout the analysis. S2

4 FT-Raman spectra were obtained using a FT-IR, NIR-FT-Raman Perkin Elmer Spectrum 2000 instrument equipped with a diode pumped Nd:YAG laser PSU and using the standard Spectrum v2.0 software. Scheme S1. Synthesis of the backfolded L. Synthesis of 4-ethynylthioanisole. This compound was prepared by a similar procedure as reported. [4] 4-Bromothioanisole (0.9 g, 4.5 mmol), Pd(PPh 3 ) 2 Cl 2 (63 mg, 0.09 mmol), PPh 3 (39 mg, 0.45 mmol) and CuI (22.5 mg, mmol) were loaded into a 25-mL Schlenk tube charged with a magnetic stirring bar. The tube was connected to a Schlenk line, evacuated and refilled with N 2 (three times). Triethylamine (10 ml) were degassed and injected into the tube via cannula under N 2. Then trimethylsilylacetylene (0.525 g, 5.4 mmol) was added under N 2. The S3

5 tube was then sealed and stirred at 100 C for 10 hours. Upon cooling to room temperature the solvents were removed in vacuo and the residue was purified by a silica gel plug (silica gel, with 20:1 hexane/ dichloromethane as the eluent) to provide 4-(trimethylsilylethynyl)thioanisole (0.89 g, yield 90% based on 4-Bromothioanisole). 1 H NMR (400 MHz, CDCl 3 ): δ 7.36 (m, 2H), 7.11 (m, 2H), 2.44 (s, 3H), 0.23 (s, 9H). 4-(trimethylsilylethynyl)thioanisole (0.88 g, 4.0 mmol) was treated with 0.1 eq. of anhydrous K 2 CO 3 in 20 ml of methanol at room temperature for 4 hours. After removal of the solvent, the product was extracted with ether and filtered. The yellow liquid was eluted through a short column (silica gel, 20:1 hexane/dichloromethane as the eluent) to provide a light yellow liquid 4- ethynylthioanisole (0.53 g, 90% yield based on 4-(trimethylsilylethynyl)thioanisole). 1 H NMR (400 MHz, CDCl 3 ): δ 7.39 (m, 2H), 7.17 (m, 2H), 3.09 (s, 1H), 2.49 (s, 3H). Synthesis of pentaerythritol tetra-p-methyl benzoate (C1). A mixture of methyl 4- hydroxybenzoate (0.67 g, 4.4 mmol), pentaerythritol tetrabromide (388 mg, 1 mmol), and potassium carbonate (1.38 g, 10 mmol) were added to a Schlenk tube charged with a stirring bar under N 2 protection. DMF (15 ml) were degassed and injected into the tube via cannula under N 2. Then the mixture was heated at 90 C overnight. After being cooled to room temperature, the mixture was then poured into 50 ml of water and extracted with dichloromethane (3 x 30 ml). The combined organic layer was washed by water (3 x 30 ml) and dried over MgSO 4. After removal of the solvent, the residue was purified by column chromatography (silica gel, 5:1 hexane/ethyl acetate as the eluent) to provide a white powder (568 mg, yield 86% based on pentaerythritol tetrabromide). 1 H NMR (400 MHz, CDCl 3 ): δ 7.96 (d, 8 H), 6.93 (d, 8 H), 4.41 (s, S4

6 8 H), 3.87 (s, 12 H). 13 C NMR (100 MHz, CDCl 3 ): δ 44.8, 51.8, 66.5, 114.2, 123.4, 131.6, 162.1, Synthesis of pentaerythritol tetra-2-br-p-methyl benzoate (C2). Pentaerythritol tetra-pmethyl benzoate (550 mg, 0.80 mmol) was added to a 25 ml Schlenk tube charged with a stirring bar. Br 2 (1.04 g, 6.40 mmol) was dissolved in CHCl 3 (8 ml) and added to the tube. After stirring at room temperature for 12 hours, 50 ml water and 200 mg NaSO 3 were added into the reaction mixture. Then the mixture was extracted by dichloromethane (3 30 ml). The combined organic layer was washed by water (3 30 ml) and dried over MgSO 4. After removal of the solvent, the residue was purified by column chromatography (silica gel, 5:1 hexane/dichloromethane as the eluent) to provide a white powder (725 mg, yield 92% based on C1). 1 H NMR (400 MHz, CDCl 3 ): δ 7.96 (d, 1H), 7.74 (t, 1H), 7.26 (s, CDCl 3 ), 7.25 (d, 1H), 3.88 (s, 3H), 3.35 (s, 2H). 13 C NMR (100 MHz, CDCl 3 ): δ , , , , , , , 77.31, 76.99, 76.67, 52.32, 45.89, Synthesis of pentaerythritol tetra-2-(4-ethynylphenyl)methylsulfane-p-methyl benzoate (C3). Bis(triphenylphosphine)palladium(II) chloride (18 mg, mmol), triphenylphosphine (36 mg), copper(i) iodide (7.5 mg), 4-ethynylthioanisole (130 mg, 0.90 mmol), C2 (200 mg, 0.20 mmol) were loaded into a 25 ml Schlenk tube charged with a magnetic stirring bar. Triethylamine (2.5 ml) and tetrahydrofuran (THF, 2.5 ml) were degassed and injected into the tube via cannula under N 2. The mixture was then stirred and heated at 90 C overnight. Upon being cooled to room temperature, the reaction mixture was poured into 50 ml of water and extracted by dichloromethane (3 20 ml). The combined organic layer was washed by water (3 30 ml) and dried over MgSO 4. After removal of the solvent, the residue was purified by S5

7 column chromatography (silica gel, 3:1 hexane/ethyl acetate as the eluent) to provide a white powder C3 (205 mg, yield 87% based on C2). 1 H NMR (400MHz, CDCl 3 ): δ 8.13 (d, 4H, CHAr), 7.75 (t, 4H, CHAr), (m, 8H, CHAr), (m, 8H, CHAr), (d, 4H, CHAr), (s, 8H, OCH 2 ), (s, 12H, OCH 3 ), (s, 12H, SCH 3 ). 13 C NMR (100MHz, CDCl 3 ): δ , , , , , , , , , , , 94.20, 84.64, 67.47, 52.09, 46.29, Synthesis of pentaeryhritol tetra-2-(4-ethynylphenyl)methylsulfane-p-methyl benzoic acid (L). A suspension of pentaeryhritol tetra-2-(4-ethynylphenyl)methylsulfane-p-methyl benzoate (C3, 100 mg, 0.08 mmol) in 12 ml 3M methanol/water (1:1, v:v) solution of KOH was refluxed for 24 hours. Upon cooling to room temperature, the reaction mixture was poured into 30 ml of water; HCl (10%) was then added slowly to the mixture with vigorous stirring. After the ph value of the mixture became lower than 2, the precipitate was collected by suction filtration, washed extensively with water to provide a white powder L (85 mg, yield 90% based on C3). The resulting product was pure as indicated by NMR and was used for crystal growth without further purification. 1 H NMR (400 MHz, DMSO-d 6 ): (s, 4H, COOH), (d, 4H, CHAr), (q, 4H, CHAr), (q, 8H, CHAr), (q, 8H, CHAr), (s, 8H, OCH 2 ), (s, 12H, SCH 3 ). 13 C NMR (DMSO-d 6, 100MHz): δ , , , , , , , , , , , 94.31, 84.94, 67.95, 45.93, Chemical analysis of the product yielded the following: Calcd [C (68.98%), H (4.36%)]; Found [C (66.08%), H (4.18%)]. Crystallization of BFMOF-1. L (7.2 mg, 6.0 μmol) and Pb(NO 3 ) 2 (6.0 mg, 18.0 μmol) were loaded into a heavy-wall glass tube (soda lime, 10 mm OD, 6 mm ID), and then a solution of S6

8 water and N,N-dimethylacetamide (1.5 ml, 1:3, v/v) was added. The tube was then flame-sealed and heated at 100 C in a programmable oven for 48 hours, followed by slow cooling (0.1 C/min) to room temperature, during which single crystals suitable for single-crystal X-ray diffraction were formed (5.2 mg, yield 56% based on L). Chemical analysis of the product Pb 6 O 2 (C 69 H 48 O 12 S 4 ) 2 (C 4 H 9 NO) 3 (H 2 O) 2 yielded the following: calcd [C (45.41%), H (3.23%), N (1.06%), S (6.47%)], found [C (45.97%), H (3.45%), N (1.08%), S (6.52%)]. IR (ν/cm 1 ): 3447 (w), 3063 (w), 2908 (w), 2202 (w), 1633 (m), 1601 (m), 1583 (m), 1536 (m), 1495 (m), 1419 (s), 1372 (s), 1294 (w), 1265 (s), 1228 (m), 1137 (w), 1098 (m), 1084 (w), 1013 (w), 818 (m), 781 (m), 745 (w), 651 (w), 525 (w). X-ray powder diffraction of the bulk sample indicated a pure phase consistent with the single-crystal structure. Transformation of BFMOF-1 into BFMOF-1a. The crystal sample of BFMOF-1 (30 mg) was immersed in ethanol (5 ml, or solvents such as CH 3 CN, CH 2 Cl 2 ) at room temperature, the framework quickly (e.g., within half an hour) transform into a new phase (designated as BFMOF-1a), as is revealed in both single crystal and powder X-ray diffraction studies. Chemical analysis of the product Pb 6 O 2 (C 69 H 48 O 12 S 4 ) 2 yielded the following: calcd [C (45.16%), H (2.64%), S (6.99%)], found [C (44.79%), H (2.72%), S (6.68%)]. 1a-PdCl 2 from treatment of BFMOF-1a with Pd(CH 3 CN) 2 Cl 2. A desolvated crystal sample (BFMOF-1a, 3.0 mg) was placed into a saturated dichloromethane solution of Pd(CH 3 CN) 2 Cl 2 (2.0 ml, 0.24 % w/w). The crystal turned from light white into dark red within several minutes. After being stirred for about 12 hours at room temperature, the dark-red crystal (designated as 1a-PdCl 2 ) was separated by centrifugation and washed by dichloromethane (5 3 ml). ICP elemental analysis revealed a Pd/Pb ratio of 2.51:1 [1a-PdCl 2 (1.52 mg) dissolved in S7

9 H 2 SO 4 /HNO 3 (1.5 ml, 1:2, v/v), then diluted to 10 ml with H 2 O, Pd and Pb concentrations found: mg/l and mg/l, respectively]. 1a-H 2 S from treatment of BFMOF-1a with H 2 S gas. Upon exposure to H 2 S gas at room temperature for 0.5 hour, the yellowish crystals of BFMOF-1a became red (see Figure S8 for details). Chemical analysis of the product Pb 6 O 2 (C 69 H 48 O 12 S 4 ) 2 (H 2 S) 2 (H 2 O) 4 yielded the following: calcd [C (43.50%), H (2.86%), S (8.42%)], found [C (42.56%), H (2.67%), S (8.47%)]. Detection of H 2 S. A BFMOF-1 crystal sample (6.0 mg) was evenly divided into six 15-mL vials. Into each of vials was then added 10 ml of each of the following NaSH solutions: 0 ppm, 1 ppm, 2 ppm, 5 ppm, 20 ppm and 100 ppm. The resultant mixtures inside were heated at 80 C for 0.5 hour. Treatment of BFMOF-1a by AgBF 4. Crystals of BFMOF-1a (3.0 mg) were placed into a toluene solution of AgBF 4 (2.0 ml, 0.29 % w/w). After being stirred for about 12 hrs at r.t., the crystal was separated by centrifugation and washed by toluene (3 ml x 5). ICP elemental analysis revealed a Ag/Pb ratio of 1.40:1 [1a-AgBF 4 (1.62 mg) dissolved in 1.5 ml H 2 SO 4 /HNO 3 (1:2, v/v), then diluted to 10 ml with H 2 O, Ag and Pb concentrations found: mg/l and mg/l, respectively]. Treatment of BFMOF-1a by HgCl 2. Crystals of BFMOF-1a (3.0 mg) were placed into a dichloromethane solution of HgCl 2 (2.0 ml, 0.25 % w/w). After being stirred for about 12hrs at r.t., the crystals were separated by centrifugation and washed by dichloromethane (3 ml x 5). ICP elemental analysis revealed a Hg/Pb ratio of 0.37:1 [1a-HgCl 2 (2.31 mg) dissolved in 1.5 ml H 2 SO 4 /HNO 3 (1:2, v/v), then diluted to 10 ml with H 2 O, Hg and Pb concentrations found: mg/l and mg/l, respectively]. Treatment of BFMOF-1a by Pt(CH 3 CN) 2 Cl 2. Crystals of BFMOF-1a (3.0 mg) were placed into a dichloromethane solution of Pt(CH 3 CN) 2 Cl 2 (2.0 ml, 0.25 % w/w). After being stirred for about 12hrs at r.t., the crystals were separated by centrifugation and washed by dichloromethane S8

10 (3 ml x 5). ICP elemental analysis revealed a Pt/Pb ratio of 0.36:1 [1a-PtCl 2 (2.40 mg) dissolved in 1.5 ml H 2 SO 4 /HNO 3 (1:2, v/v), then diluted to 10 ml with H 2 O, Pt and Pb concentrations found: mg/l and mg/l, respectively]. Treatment of BFMOF-1a by CdCl 2. Crystals of BFMOF-1a (3.0 mg) were placed into a dichloromethane/ethanol (1:1, v/v) solution of CdCl 2 (2.0 ml, 0.25 % w/w). After being stirred for about 12 hrs at r.t., the crystals were separated by centrifugation and washed by ethanol (3 ml x 5). ICP elemental analysis revealed a Cd/Pb ratio of 0.26:1 [1a-CdCl 2 (2.18 mg) dissolved in 1.5 ml H 2 SO 4 /HNO 3 (1:2, v/v), then diluted to 10 ml with H 2 O, Cd and Pb concentrations found: mg/l and mg/l, respectively]. Figure S1. Thermogravimetric analysis (TGA) plots of as-made BFMOF-1 (solid line) and BFMOF-1a (dashed line). The weight loss (7.60%) between 100 and 300 C corresponds to the departure of the DMA and water molecules from the composition Pb 6 O 2 (C 69 H 48 O 12 S 4 ) 2 (DMA) 3 (H 2 O) 2 for BFMOF-1 (calcd DMA and water content: 7.49%). S9

11 Figure S2. Topological representations of the Pb-carboxyl net in BFMOF-1 (a) and BFMOF-1a (b) along the a axis. The two sphalerite-like (diamondoid ZnS-like) subnets are shown in grey and red connections, respectively. Purple sphere: geometric center of the Pb 6 O 2 core; green node: geometric center of L. Figure S3. The IR spectra of BFMOF-1 (a), BFMOF-1a (b) and BFMOF-1 sample after being treated with DMA at 120 C for 12 hours (c). S10

12 Figure S4. CO 2 sorption isotherm at 273 K for a desolvated sample of BFMOF-1a (left) and the corresponding pore size distribution (right). Figure S5. Photo images of the powder samples of BFMOF-1a (a); 1a-PdCl 2 (b) this sample was made from treating sample (a) by a saturated dichloromethane solution of Pd(CH 3 CN) 2 Cl 2 for 12 hrs; and 1a-Pd-H 2 (c) this sample was made from treating sample (b) by a H 2 atmosphere for 3 hrs. S11

13 Figure S6. Diffuse reflectance spectra of BFMOF-1-related systems: a desolvated sample BFMOF-1a (a); an as-made sample of BFMOF-1 (b); 1a-PdCl 2 (c); 1a-Pd-H 2 (d). Figure S7. Photo images of the BFMOF-1a crystallites under natural light (top row, scale bar: 1 mm) and under 365 nm UV radiation (bottom row, scale bar: 5 mm) after stirred for 12 hrs at rt in solution of a) CH 2 Cl 2 ; b) Pd(CH 3 CN) 2 Cl 2 in CH 2 Cl 2 ; c) AgBF 4 in toluene; d) HgCl 2 in CH 2 Cl 2 ; e) Pt(CH 3 CN) 2 Cl 2 in CH 2 Cl 2 and f) CdCl 2 in 1:1 CH 2 Cl 2 /C 2 H 5 OH. S12

14 Figure S8. Scanning electron microscopy (SEM) images of the crystal samples of: a) BFMOF-1a; b) 1a- PdCl 2 and c) 1a-Pd-H 2. Figure S9. Photo images of the powder samples of BFMOF-1a (a) and 1a-H 2 S (b). S13

15 Figure S10. UV-visible emission spectra of BFMOF-1 (a) and desolvated BFMOF-1a (b) under the excitation of 370 nm. Figure S11. X-ray photoelectron spectroscopy (XPS) peaks of the 4f 7/2 and 4f 5/2 states of the Pb(II) centers in BFMOF-1a (blue) and 1a-H 2 S (red). S14

16 Single Crystal X-ray Crystallography. Table S1. Experimental details For all structures: triclinic, P1. Crystal shape: plate. Experiments were carried out at 100 K with Mo K radiation. Refinement was carried out on F 2. H-atom parameters were constrained. Crystal data Chemical formula C 72 H 55 NO 14 Pb 3 S 4 2(C 3 H 7 NO) BFMOF-1-DMF BFMOF-1 BFMOF-1a C 138 H 96 O 26 Pb 6 S 8 H 2 O 3(C 4 H 9 NO) M r a, b, c (Å) (11), (15), (16),, ( ) (1), (1), (1) (16), (2), (2) (16), (18), (18) C 138 H 96 O 26 Pb 6 S (4), (5), (6) (6), (7), (6) V (Å 3 ) (5) (8) (19) Z F(000) D x (Mg m -3 ) No. of reflections for cell measurement range ( ) for cell measurement (mm -1 ) Colour Yellow Colourless Colourless Crystal size (mm) Data collection Diffractometer Bruker AXS SMART APEX CCD diffractometer Bruker AXS APEXII CCD diffractometer S15 Bruker AXS APEXII CCD diffractometer Radiation source fine-focus sealed tube fine focus sealed tube fine focus sealed tube Monochromator Graphite Graphite Graphite Scan method scans and phi scans and phi scans Absorption correction Multi-scan Apex2 v (Bruker, 2011) Analytical from face indices Apex2 v (Bruker, 2013) Analytical from face indices Apex2 v (Bruker, 2013) T min, T max 0.505, , , No. of measured, 43053, 21762, , 15282, , 12026, 7750

17 independent and observed [I > 2 (I)] reflections R int values ( ) max = 31.2, min = 1.3 max = 26.4, min = 2.2 max = 25.4, min = 2.4 (sin / ) max (Å -1 ) Range of h, k, l h = , k = , l = h = , k = , l = h = , k = , l = Refinement R[F 2 > 2 (F 2 )], wr(f 2 ), S 0.034, 0.079, , 0.108, , 0.167, 1.10 No. of reflections No. of parameters No. of restraints w = 1/[ 2 (F o 2 ) + (0.0278P) P] where P = (F o 2 + 2F c 2 )/3 w = 1/[ 2 (F o 2 ) + (0.0629P) P] where P = (F o 2 + 2F c 2 )/3 ( / ) max w = 1/[ 2 (F o 2 ) + (0.0888P) 2 ] where P = (F o 2 + 2F c 2 )/3 max, min (e Å -3 ) 1.64, , , Computer programs: Apex2 v (Bruker, 2011), Apex2 v (Bruker, 2013), Apex2 v , SAINT V8.30C (Bruker, 2013), SHELXTL 6.14 (Bruker, 2003; Sheldrick, 2008), SHELXS97 (Sheldrick, 2008), SHELXTL 6.14, SHELXL2013 (Sheldrick, 2013), SHELXLE Rev645 (Hübschle et al., 2011), SHELXTL (Bruker, 2003). Refinement details: BFMOF-1-DMF: Reflections and were partially obstructed by the beam stop and were omitted from the refinement. Two pairs of DMF molecules are disordered around a crystallographic inversion center with a refined occupancy ratio of 0.526(9) to 0.474(9). The two DMF molecules were restrained to have S16

18 geometries similar to that of another not disordered DMF molecule, and atoms with substantial overlap (O3 and O4, C10 and C13) were constrained to have identical ADPs. BFMOF-1: Sections of the core of the ligand show pronounced vibration and/or disorder. These sections were refined as disordered over two positions. The two moieties were restrained to have similar geometries (SAME and SADI restraints in Shelxl). One pair of disordered benzene rings were constrained to resemble ideal hexagons with C-C bond lengths of 1.39 Angstroms (AFIX 66 in Shelxl). Atoms C41 and C41B of the alkyne group directly bonded to the constrained benzene rings were constrained to have identical atom positions (thus to be not disordered, EXYZ in Shelxl). ADPs of equivalent disordered atoms were constrained to be identical (EADP in Shelxl). Atoms O4, O7, O10, O13, C65, C66, C67, C68 and C69 and their disordered counterparts were also subjected to a rigid bond restraint (RIGU in Shelxl). Atoms S3, C34 and C48 were restrained to have close to isotropic ADPs (ISOR in Shelxl). Two crystallographically distinct DMA solvate molecules are located in the crystal structure. One of the two is disordered across an inversion center and hydrogen bonded to a water molecule, and both the DMA and water molecule were refined as half occupied. The geometry of the DMA molecule was restrained to be similar to that of the not disordered DMA molecule. The ADPs of the atoms of the disordered DMA molecule were restrained using a rigid bond restraint (RIGU in Shelxl) and to be close to isotropic (ISOR in Shelxl). The structure contains additional solvent accessible voids of 262 Ang3. No substantial electron density was found in the solvent accessible voids, with all residual electron density peaks in the voids being below two electrons per cubic Angstrom and not arranged in an interpretable pattern. Treatment using the Squeeze procedure of Platon revealed only 35 electrons for each void of 262 Ang3, with no substantial improvement of refinement quality or R values. The void volume was thus left uncorrected for and no attempts were made to establish a solvent model for these regions. S17

19 Several low angle reflections were affected by the beam stop and were omitted from the refinement. The omitted reflections were , , 0 1 0, 0-1 1, 0 0 1, 0 1 1, 1 0 0, 0 0 2, 0-1 2, 1 1 0, , 1 2 0, 1-1 1, and BFMOF-1a: Several low angle reflections showed signs to be affected by the beam stop and were omitted from the refinement. The reflections in question were , 1 0 0, , 0-1 1, 0 1 0, and Two 4-thiomethylphenylene groups were refined as disordered over two positions to model large vibration. For one of the rings, C42-C48, the phenyl rings were constrained to resemble ideal hexagons with C-C distances of 1.39 Angstrom. For all disordered 4-thiomethylphenylene groups the major and minor units were restrained to have similar geometries. Equivalent disordered carbon and sulfur atoms were constrained to have identical ADPs, and all disordered atoms were subjected to a rigid bond restraint (RIGU in Shelxl). Structural irregularities arising from the single-crystal-to-single-crystal transformation manifest themselves in large residual electron density peaks. Location of the peaks with respect to each other indicate the presence of a second minor polymorph with the residual electron density peaks being associated with the lead atoms of that second phase. The structure used for this cif file features four such peaks above 3 electrons per cubic Angstrom: Q Q Q S18

20 Q Screening of large numbers of crystals prepared in different ways did reliably reproduce the pattern of the large residual densities, with only slight variations in electron density. Use of smaller crystals or cutting of larger crystals did not yield smaller residual electron densities. No electron density for carbon or oxygen atoms is resolved in the difference maps, so no attempts were made to refine the second polymorph of the disordered structure or intergrowth crystal. To avoid physically meaningless thermal displacement parameters, atoms close to the major residual electron density peaks were restrained. C49 and C33 were restrained to be approximately isotropic (ISOR 0.003). Atoms O11, O12, C49, C50, C51 and C55, and atoms O8, O9, C33, C34, C35 and C39 were subjected to a rigid bond restraint. Reference [1] Apex2 v (Bruker, 2013) Bruker Advanced X-ray Solutions, Bruker AXS Inc., Madison, Wisconsin, USA. [2] a) SHELXTL (Version 6.14) ( ) Bruker Advanced X-ray Solutions, Bruker AXS Inc., Madison, Wisconsin: USA. b) Sheldrick, G. M. (2008). Acta Cryst. A64, [3] Sheldrick, G. M. (2013). University of Göttingen, Germany. [4] a) C. Dai, Z. Yuan, J. C. Collings, T. M. Fasina, R. L. Thomas, K. P. Roscoe, L. M. Stimson, D. S. Yufit, A. S. Batsanov, J. A. K. Howard, T. B. Marder, CrystEngComm 2004, 6, ; b) W. B. Austin, N. Bilow, W. J. Kelleghan, K. S. Y. Lau, The Journal of Organic Chemistry 1981, 46, S19