A highly permeable benzotriptycene-based. Polymer of Intrinsic Microporosity.

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1 Supporting Information for A highly permeable benzotriptycene-based Polymer of Intrinsic Microporosity. Ian Rose, Mariolino Carta, Richard Malpass-Evans, Maria-Chiara Ferrari, Paola Bernardo, Gabriele Clarizia, Johannes C. Jansen, Neil B. McKeown * School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ, UK Institute for Materials and Processes, School of Engineering, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JL, UK Institute on Membrane Technology, ITM-CNR, c/o University of Calabria, Via P. Bucci 17/C, Rende (CS), Italy General methods and equipment Commercially available reagents were used without further purification. Anhydrous dichloromethane was obtained by distillation over calcium hydride under nitrogen atmosphere. Anhydrous N,N-dimethylformamide was bought from Aldrich. All reactions using air/moisture sensitive reagents were performed in oven-dried or flame-dried apparatus, under a nitrogen atmosphere. TLC analysis refers to analytical thin layer chromatography, using aluminium-backed plates coated with Merck Kieselgel 60 GF 254. Product spots were viewed either by the quenching of UV fluorescence, or by staining with a solution of Cerium Sulfate in aqueous H2SO4. Flash chromatography was performed on silica gel 60A (35-70 micron) chromatography grade (Fisher Scientific). Microwaved irradiation synthesis was performed with a CEM Discover microwave reactor. Melting points were recorded using a Gallenkamp Melting Point Apparatus and are uncorrected. 1 H NMR spectra were recorded in the solvent stated using an Avance Bruker DPX 400 (400 MHz) or DPX 500 (500 MHz) instruments, with 13 C NMR spectra recorded at 100 MHz or 125 MHz respectively. Lowresolution mass spectrometric data were determined using a Fisons VG Platform II quadrupole instrument using electron impact ionization (EI) unless otherwise stated. High- 1

2 resolution mass spectrometric data were obtained in electron impact ionization (EI) mode unless otherwise reported, on a Waters Q-TOF micromass spectrometer. Low-temperature (77 K) N 2 adsorption/desorption measurements of PIM powders were made using a Coulter SA3100. Samples were degassed for 800 min at 120 C under high vacuum prior to analysis. The TGA was performed using the device Thermal Analysis SDT Q600 at a heating rate of 10 C/min from room temperature to 1000 C. Elemental analysis was carried out with a Carlo Erba EA1101 elemental analyser. Gel Permeation Chromatography was carried out using a Viscotek GPC Max1000 system which includes a refractive index detector and two 2 columns (KF-805L Shodex). The analysis used a dilute solution of polymer in chloroform (1 ml min -1 ). Viscosity measurement were carried out with an Ubbelhode capillary (Nr /0, Schott Germany) on a SCHOTT Instruments GmbH: AVS 370, maintaining 25 C, using CHCl 3 as solvent with g cm -3 concentration. Tensile tests were carried out at room temperature on methanol treated membrane samples, with a Zwick/Roell single column Universal Testing Machine, model Z2.5, equipped with a 50N load cell and flat grinded steel pneumatic clamps. Specimens with an effective length of mm (distance between the clamps) and a width of 5 mm were tested at a deformation rate of 10 % min -1 ( mm min -1 ). The average value and the standard deviation of the Young s modulus, the tensile strength and the maximum deformation were determined on a series of 4-6 samples. Background Gas permeation The rate of gas permeation through a membrane is expressed by a permeability coefficient, Pi. It is obtained as the observed steady-state flux Ni divided by the driving partial pressure (Δpi) across the membrane, normalized by the membrane thickness l N P = i i Δpi (1) l Gas permeation in dense polymeric films occurs via a so-called solution-diffusion mechanism. The penetrant first sorbs at the high pressure side of the film, diffuses through the membrane, driven by a concentration, gradient and desorbs at the low pressure side of the membrane. Therefore, the permeability can be expressed as the product of two factors: the diffusion coefficient, D and the solubility S. P = D S (2) The first is a kinetic term that characterizes the mobility of the penetrant molecule in the membrane, while the latter is a thermodynamic factor that characterizes uptake concentration of the penetrant at a given fugacity or partial pressure 2

3 S i = C i /p i (3) where C i is the concentration of sorbed gas in the unit volume of polymer matrix and p i is the external gas partial pressure, or fugacity for non-ideal feeds. The ideal selectivity, or Permselectivity, between two gases provides a useful measure of the separation performance of a membrane. It is defined as the ratio of the single gas permeabilities, when the downstream pressure is negligible relative to the upstream pressure, as in this study. It can be decoupled into a solubility-selectivity and a diffusivity-selectivity: α A/B = P A /P B = (D A /D B ) (S A /S B ) Gas Permeation Measurements Gas permeabilities of the PIM-BTrip-TB membranes were measured in a constant volume/varying pressure apparatus at 25 C. The gases used for the tests were He, H 2, O 2, N 2, CH 4 and CO 2 (purity of %, SAPIO, Italy). The samples were carefully evacuated and degassed completely before the measurements. The increase of the pressure in the permeate side as a function of time was recorded as soon as the membrane was exposed to the feed gas at a pressure in the range of bar. The whole permeation curve takes the following form 1 : (4) n 2 2 RT A l D t 1 2 ( 1) D n π t pt = p0 + ( dp / dt) t + p exp 0 f S VP V (5) m l 6 π 1 n l in which p t is the permeate pressure at time t and p 0 is the starting pressure, typically less than mbar. The baseline slope (dp/dt) 0 is usually negligible for a defect-free membrane. R is the universal gas constant, T is the absolute temperature, A is the exposed membrane area, V P is the permeate volume, V m is the molar volume of a gas in standard conditions (0 C and 1 atm), p f is the feed pressure, S is the gas solubility, D is the gas diffusion coefficient and l the membrane thickness. The Time Lag method 2 was applied to the recorded data to determine the gas diffusion coefficient. The permeability coefficient, P, is calculated from the following equation, describing the steady state permeation: 3

4 2 RT A pf P l pt = p0 + ( dp / dt) t + t 0 VP Vm l 6D (6) The last term in Eq. (6) corrects for the so-called permeation time lag, Θ, which is inversely proportional to the diffusion coefficient of the gas: 2 l Θ= (7) 6 D The gas solubility coefficient, S, was obtained indirectly as the ratio of the permeability to the diffusion coefficient by assuming the solution-diffusion transport mechanism: S = P / D (8) The exposed membrane area in the permeation tests was of 2.14 cm 2. Permeabilities are reported in units of Barrer (1 Barrer = cm 3 (STP) cm cm -2 s -1 cmhg -1 ). Measurements were carried out on freshly prepared samples, MeOH treated samples just after the treatment and after 5 months. 4

5 Table S1. Physical characterisation of the PIM-BTrip-TB compared with PIM-EA-TB and PIM-Trip-TB. Polymer BET surface area (m 2 g 1 ) Total pore volume (cm 3 g 1 ) at p/p 0 = 0.98 M w 10 3 (g mol 1 ) PDI (-) Inherent Viscosity (cm 3 g 1 ) TGA Decomposition Temperature ( C) PIM-BTrip-TB PIM-Trip-TB PIM-EA-TB Table S2. Gas permeabilities P x, diffusivity D x, solubility coefficient S x and ideal selectivities α (P x /P y ) for a methanol treated film of PIM-BTrip-TB, PIM-Trip-TB 12 and PIM- EA-TB. 13 Sample Transport parameters N 2 O 2 CO 2 CH 4 H 2 He Selectivity α (P x/p N2) [-] H 2/N 2 H 2/CH 4 CO 2/CH 4 O 2/N 2 PIM-BTrip-TB P x [Barrer] PIM-BTrip-TB Aged 166 days D x [10-12 m 2 /s] D x/d N2 [-] S x [cm 3 cm -3 bar -1 ] S x/s N2 [-] P x [Barrer] D x [10-12 m 2 /s] D x/d N2 [-] S x [cm 3 cm -3 bar -1 ] S x/s N2 [-] PIM-Trip-TB P x [Barrer] D x [10-12 m 2 /s] >10000 a D x/d N2 [-] >74 a S x [cm 3 cm -3 bar -1 ] S x/s N2 [-] PIM-EA-TB P x [Barrer] D x [10-12 m 2 /s] >7000 a >10000 a D x/d N2 [-] >90 a 116 S x [cm 3 cm -3 bar -1 ] <0.8 a <0.8 a S x/s N2 [-] <0.06 a <0.02 a a Minimum approximation for D and maximum approximation for S due to slight overestimation of the very short time lag. 5

6 Materials 2,6-Diaminoanthranone 2,6-Diaminoanthranone was prepared according to the procedure reported by Revell et al. 5. 2,6-Diaminoanthraquinone (20.0 g, 84.0 mmol), tin powder (59.8 g, mmol), 2.5 M aqueous NaOH (350 ml) and ethanol (400 ml) were combined and heated to reflux for 24 h under N 2 atmosphere. The hot mixture was then poured into water (2 L) and stirred for 20 min. The resulting solid was filtered, washed with water and dried at 100 C to give 2,6- Diaminoanthranone (16.0 g, 71.3 mmol, 85 %) as a light brown solid. Mp: 280 ºC (dec); vmax (cm -1 ): 3421, 3331, 3196, 1645, 1564, 1322; 1 H NMR (500 MHz, (CD 3 ) 2 SO): δh (ppm) = 7.87 (d, J = 8.6 Hz, 1H, Ar H), 7.32 (d, J = 2.6 Hz, 1H, Ar H), 7.16 (d, J = 8.2 Hz, 1H, Ar H), 6.85 (dd, J = 8.2, 2.6 Hz, 1H, Ar H), 6.62 (d, J = 6.4 Hz, 1H, Ar H), 6.54 (s, 1H, Ar H), 6.04 (s, 2H, CH), 5.19 (s, 2H, NH), 4.05 (s, 2H, NH); 13 C NMR (101 MHz, (CD 3 ) 2 SO): δc (ppm) = , , , , , , , , , , , , , 31.46; LRMS (EI, m/z): calculated: found: ,6-Diaminoanthracene (1) 2,6-Diaminoanthracene was prepared according to the procedure reported by Revell et al. 5. 2,6-Diaminoanthranone (16.0 g, 71.0 mmol), NaBH 4 (21.59 g, 571 mmol), ethanol (300 ml) and 2.5 M aq NaOH (300 ml) were combined and heated to reflux for 6 h. The hot mixture was poured into water (1 L) and stirred for 20 min. The resulting solid was filtered and extracted with acetone. The solvent was removed under vacuum. Resulting solid was washed with small amount of cold acetone, filtered and dried to give 2,6-Diaminoanthracene (8.0 g, 38.4 mmol, 54 %) as a yellow solid. Mp: ºC (Lit C); vmax (cm -1 ): 3403, 3326, 3204, 3009, 2957, 1635, 1475; 1 H NMR (400 MHz, (CD 3 ) 2 SO): δh (ppm) = 7.88 (s, 2H, Ar H), 7.64 (d, J = 8.9 Hz, 2H, Ar H), 6.93 (d, J = 8.9 Hz, 2H, Ar H), 6.80 (s, 2H, Ar H), 5.24 (bs, 4H, NH); 13 C NMR (101 MHz, (CD 3 ) 2 SO): δc (ppm) = , , , , , , ; LRMS (EI, m/z): calculated: found: ,4-Dihydro-1,4-epoxynaphthalene (2) 6

7 1,4-Dihydro-1,4-epoxynaphthalene was prepared according to the procedure reported by Luo et al. 7. 1,2-Dibromobenzene (30.0 g, mmol) in anhydrous THF (40 ml) and Furan (64.73 ml, mmol) was treated drop wise with 2.5 M BuLi in hexane (66.12 ml, mmol) in anhydrous THF (20 ml) at -78 C. The solution was stirred at -78 C for 1.5 h. Distilled water (30 ml) was added to the reaction mixture and left to warm to room temperature. DCM was added, separated, extracted and dried over anhydrous MgSO 4. Solvent removed under vacuum and purified by recrystallisation to give 1,4-Dihydro-1,4- epoxynaphthalene (7.34 g, 51.0 mmol, 40 %) as a white solid. Mp: 56-57ºC (Lit 8 56ºC); vmax (CH 2 Cl 2 /cm -1 ): 3021, 1450, 1279, 987, 871, 845; 1 H NMR (500 MHz, CDCl 3 ): δh (ppm) = 7.27 (dd, J = 4.07, 1.70, 2H, Ar H), 7.05 (t, J = 1.03, 2H, CH), 6.99 (dd, J = 5.11, 2.97, 2H, Ar H) 5.73 (m, 2H, CH); 13 C NMR (101 MHz, CDCl 3 ) δc (ppm) = 149.0, 143.0, 125.0, 120.3, 82.4; LRMS (EI, m/z): Calculated: found: Adduct (3) Adduct 3 was prepared according to a modified procedure reported by T. M. Swager 9. 2,6- Diaminoanthracene (3.00 g, 14.4 mmol) and 1,4-dihydro-1,4-epoxynaphthalene (2.08 g, 14.4 mmol) were dissolved in DMF (15.0 ml) and heated in microwave reactor at 250ºC for 2.5 h at 7 bar pressure. Solvent was removed under vacuum and the residue was purified by column chromatography with CHCl 3 / ethyl acetate (1:1, v/v) to yield IR29 (4.55 g, 12.9 mmol, 90 %) as a yellow/brown solid. Mp: 250ºC (dec); vmax (CH 2 Cl 2 /cm -1 ): 3350, 3008, 2933, 1625, 1483, 1266; 1 H NMR (500 MHz, CDCl 3 ): δh (ppm) = 7.14 (dd, J = 5.25, 3.05 Hz, 2H, Ar H), 7.05 (dd, J = 5.5, 3.0 Hz, 2H, Ar H), 7.03 (d, J = 8.5 Hz, 1H, Ar H), 6.98 (d, J = 7.77 Hz, 1H, Ar H), 6.69 (d, J = 2.27 Hz, 1H, Ar H), 6.62 (d, J = 2.29 Hz, 1H, Ar H), 6.46 (dd, J = 7.68, 2.29 Hz, 1H, Ar H), 6.33 (dd, J = 7.77, 2.30 Hz, 1H, Ar H) 4.93 (s, 1H), 4.92 (s, 1H), 4.20 (dd, J = 6.12, 2.61 Hz, 2H, CH), 3.51 (s, 4H), (m, 2H); 13 C NMR (101 MHz, CDCl 3 ) δc (ppm) = , , , , , , , , , , , , , , , , 81.40, 81.26, 49.45, 48.63, 46.93, 46.80; LRMS (EI, m/z): Calculated: found: ,12[1',2']-Benzenonaphthacene-2,16-diamine, 5,12-dihydro (4) 2,6-Diaminobenzotriptycene was prepared according to the procedure reported by T. M. Swager 9. Adduct (3.03 g, 8.60 mmol), ethanol (120 ml) and perchloric acid (70 %, 40.0 ml) 7

8 were combined and heated to reflux for 24 h. The resulting mixture was cooled and poured into ice-water (300 ml) and neutralised with aqueous NaOH solution. This was then extracted using CHCl 3, dried over MgSO 4 and solvent removed under vacuum. Crude product was purified by column chromatography with CHCl 3 / ethyl acetate (7:3, v/v), washed with cold DCM and dried to yield 2,6-Diaminobenzotriptycene (1.31 g, 3.93 mmol, 46 %) as an off white solid. Mp: 235 ºC (Lit ºC); vmax (CH 2 Cl 2 /cm -1 ): 3350, 3009, 1622, 1479; 1 H NMR (500 MHz, CDCl 3 ): δh (ppm) = 7.72 (s, 2H, Ar H), 7.70 (dd, J = 6.15, 3.16 Hz, 2H, Ar H), 7.37 (dd, J = 6.17, 3.07 Hz, 2H, Ar H), 7.17 (d, J = 7.81 Hz, 2h, Ar H), 6.81 (d, J = 2.27 Hz, 2H, Ar H), 6.32 (dd, J = 7.80, 2.29 Hz, 2H, Ar H), 5.30 (s, 2H), 3.53 (bs, 4H); 13 C NMR (101 MHz, CDCl 3 ) δc (ppm) = , , , , , , , , , , , 53.01; LRMS (EI, m/z): Calculated: found: PIM-BTrip-TB Under a nitrogen atmosphere, 2,6-Diaminobenzotriptycene (1.31 g, 3.92 mmol) was dissolved in dichloromethane (2.0 ml) and dimethoxymethane (1.73 ml, 19.6 mmol) and the solution was cooled in an ice bath. Trifluoroacetetic acid (10 ml) was added drop-wise over 30 min and stirred for 24 h at room temperature. The viscous yellow mixture was poured into aqueous ammonium hydroxide solution and stirred vigorously for 2 h. Solid collected by filtration, washed with water and then acetone until the washings were clear. The resulting powder was dissolved in chloroform and methanol was added drop-wise until the solution became turbid. The solution was stirred for a further 30 min to precipitate a gel. The reprecipitation from chloroform was repeated twice. The crude polymer was dissolved in chloroform (50 ml) and added drop-wise to n-hexane with vigorous stirring and the precipitated fine powder was filtered. The cream powder was refluxed in methanol for 24 h, filtered and then dried in a vacuum oven at 120 C for 9 h to afford the desired polymer (1.18 g, 81%) as cream powder. vmax (CHCl 3 /cm -1 ): 3414, 2953, 1680, 1464, 1420, 937, 747; 1 H NMR (500 MHz, CDCl 3 ): δh (ppm) = (bm, 10H, Ar H), 5.11 (bs, 2H, CH), 4.47 (bs, 2H, CH), 3.92 (bs, 2H, CH); δc (ppm) = , , , , , , , , , , 66.88, 58.43, 52.61; Gel Permeation Chromatography, eluent = chloroform, calibrated against polystyrene standards: M n = 29,208, M w = 103,499. BET surface area = 868 m 2 /g; total pore volume = cm 3 /g at (p/p o = ), TGA analysis (nitrogen): 465 C 8

9 Figure S1. GPC trace for PIM-BTrip-TB Figure S2. Nitrogen adsorption isotherm (77 K) of PIM-TBs 9

10 Uptake (cm3(stp)/g Pressure (bar) Figure S3. Carbon dioxide adsorption isotherm (273 K) of PIM-BTrip-TB. Figure S4. Gravimetric Thermal Analysis of PIM-TBs 10

11 A B C Figure S5. Young s modulus (A), tensile strength (B) and maximum strain (C) of PIM-BTrip-TB and other TB-based PIM membranes in comparison with PIM-1. Note that the tensile strength and strain at break of PIM-BTrip-TB are slightly underestimated because for three out of five specimens the maximum of the load cell was reached before breakage. References for ESI 1. Jansen, J. C.; Friess, K.; Drioli, E., Organic vapour transport in glassy perfluoropolymer membranes: A simple semi- quantitative approach to analyze clustering phenomena by time lag measurements. Journal of Membrane Science 2011, 367 (1-2), Crank, J., The Mathematics of Diffusion. 2d Ed. 1975; p 414 pp. 3. Carta, M.; Croad, M.; Malpass- Evans, R.; Jansen, J. C.; Bernardo, P.; Clarizia, G.; Friess, K.; Lanc, M.; McKeown, N. B., Triptycene Induced Enhancement of Membrane Gas Selectivity for Microporous Troeger's Base Polymers. Advanced Materials 2014, 26 (21), Carta, M.; Malpass- Evans, R.; Croad, M.; Rogan, Y.; Jansen, J. C.; Bernardo, P.; Bazzarelli, F.; McKeown, N. B., An Efficient Polymer Molecular Sieve for Membrane Gas Separations. Science) 2013, 339 (6117), Kantam, R.; Holland, R.; Khanna, B. P.; Revell, K. D., An optimized method for the synthesis of 2,6- diaminoanthracene. Tetrahedron Letters 2011, 52 (39), Rabjohns, M. A.; Hodge, P.; Lovell, P. A., Synthesis of aromatic polyamides containing anthracene units via a precursor polymer approach. Polymer 1997, 38 (13), Luo, R.; Liao, J.; Xie, L.; Tang, W.; Chan, A. S. C., Asymmetric ring- opening of oxabenzonorbornadiene with amines promoted by a chiral iridium- monophosphine catalyst. Chemical Communications 2013, 49 (85), Wolthuis, E., Synthesis of Some Methyl- Substituted Anthracenes. The Journal of Organic Chemistry 1961, 26 (7), Sydlik, S. A.; Chen, Z.; Swager, T. M., Triptycene Polyimides: Soluble Polymers with High Thermal Stability and Low Refractive Indices. Macromolecules 2011, 44 (4),