Supporting Information

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1 Supporting Information For the manuscript Catalyst-free Preparation of Melamine-based Microporous Polymer Networks through Schiff Base Chemistry by Matthias Georg Schwab, + Birgit Faßbender, + Hans Wolfgang Spiess, + Arne Thomas, #,* Xinliang Feng +,* and Klaus Müllen +,* + Max Planck Institute for Polymer Research Ackermannweg 1, D Mainz, Germany feng@mpip-mainz.mpg.de muellen@mpip-mainz.mpg.de # Max Planck Institute of Colloids and Interfaces Research Campus Golm, D Potsdam, Germany arne.thomas@mpikg.mpg.de S1

2 Materials and methods Melamine, terephthalaldeyde and isophthalaldehyde were received from Sigma-Adrich. 4,4'- biphenyldicarboxaldehyde was received from Acros Organics. Anhydrous dimethyl sulfoxide was purchased from Riedel-de Haën Chemicals. All chemicals were used without further purification. Tris(4-formylphenyl)benzene was synthesized in 76 % yield according to a literature procedure 1. Elemental composition was determined with a Foss Heraeus Vario EL instrument. Fourier transform infrared (FTIR) spectra were collected with a Nicolet 73 spectrometer, equipped with an attenuated total reflection (ATR) setup. The 13 C {1H} cross-polarization magic angle spinning (CP-MAS) NMR spectrum was obtained on a Bruker ASX 5 MHz at MHz and a MAS frequency of 25 khz. The 15 N { 1 H} CP-MAS spectrum was obtained on a Bruker DSX 3 MHz at 21.7 MHz employing a MAS frequency of 1 khz. The 13 C and 15 N cross-polarization were performed using a contact time of 3 ms and 7 ms, respectively, and a high-power 1 H decoupling two-pulse, phasemodulation (TPPM) 2 of 1 khz. Both the 13 C and 15 N NMR spectra were referenced with respect to tetramethyl silane 3 using adamantane ( 13 C, ppm) 4 and nitromethane ( 15 N, ppm) 5 as secondary standards. All spectra were acquired at room temperature. TGA measurements were performed on a Mettler TGA/SDTA 851e thermobalance at a heating rate of 1 K/min under nitrogen. SEM measurements were performed on a LEO 153 field emission scanning electron microscope. Nitrogen sorption experiments and micropore analysis were conducted at C using an Autosorb-1 from Quantachrome Instruments. Before sorption measurements, the samples were degassed in vacuum overnight at 15 C. NLDFT pore-size distributions were determined using the carbon/slit-cylindrical pore model of the Quadrawin software. Pore volumes at p/p =.1 and p/p =.8 were converted into the corresponding liquid volumes using a nitrogen density of g/cm 3 (gaseous) and g/cm 3 (liquid). S2

3 Experimental section General considerations To ensure consistency between syntheses and to exclude concentration effects, the SNW networks were synthesized at fixed overall molar concentration of.4 M, a constant reaction temperature of 18 C as well as a molar ratio of amine to aldehyde groups of 1:1. Synthesis of SNW-1 A flame dried Schlenk flask fitted with a condenser and a magnetic stirring bar was charged with melamine (313 mg, mmol), terephthalaldehyde (5 mg, mmol) and dimethyl sulfoxide (15.5 ml). After degassing by argon bubbling the mixture was heated to 18 C for 72 h under an inert atomosphere. After cooling to room temperature the precipitated SNW network was isolated by filtration over a Büchner funnel and washed with excess acetone, tetrahydrofurane and dichloromethane. The solvent was removed under vacuum at room temperature to afford the materials as off-white powders in 61 % yield. Elemental analysis: for C36H32N24, calculated: C, 53.99; H, 4.3; N, %. Found: C, 39.5 ; H, 4.55; N, 39.39; S, 1.52 %. Synthesis of SNW-2 In a fashion similar to the preparation of SNW-1 melamine (2 mg, mmol) and 4,4'- biphenyldicarboxaldehyde (5 mg, mmol) were reacted in dimethyl sulfoxide (9.9 ml) at 18 C for 72 h to afford SNW-2 in 62 % yield. Elemental analysis: for C48H36N12, calculated: C, 63.15; H, 4.12; N, %. Found: C, 4.31; H, 4.57; N, 35.94; S, 3.44 %. Synthesis of SNW-3 In a fashion similar to the preparation of SNW-1 melamine (313 mg, mmol) and isophthalaldehyde (5 mg, mmol) were reacted in dimethyl sulfoxide (15.5 ml) at 18 C for 72 h to afford SNW-3 in 62 % yield. Elemental analysis: for C3H26N12, calculated: C, 53.99; H, 4.3; N, %. Found: C, 41.31; H, 4.77; N, 4.42; S, 3.85 %. Synthesis of SNW-4 In a fashion similar to the preparation of SNW-1 melamine (125 mg,.981 mmol) and tris(4- formylphenyl)benzene (383 mg,.981 mmol) were reacted in dimethyl sulfoxide (4.9 ml) at 18 C for 72 h to afford SNW-3 in 66 % yield. Elemental analysis: for C3H23N6, calculated: C, 67.11; H, 4.44; N, %. Found: C, 46.57; H, 4.41; N, 41.73; S,.6 %. S3

4 Pyrolysis of SNW-1 A sample of SNW-1 (6 mg) was placed in a quartz boat and heated to 45 C during 1 h under an argon flow. The sample was held at this temperature for 6 h. After cooling, the sample (29 mg) was recovered as a black powder. Elemental analysis: C, 46,96 ; H, 1,26; N, 38,28; S,,1 %. S4

5 Fourier transform infrared (FTIR) spectroscopy % transmission / a.u SNW-1 SNW-2 SNW-3 SNW wavenumber / cm -1 Figure S1. Fourier transform infrared (FTIR) spectra of SNW-1 (blue), SNW-2 (red), SNW-3 (green) and SNW-4 (purple) % Extinktion transmission Wellenzahlen (cm-1) wavenumber / cm Figure S2. Fourier transform infrared (FTIR) spectra of SNW-1. S5

6 % transmission Extinktion Wellenzahlen wavenumber /(cm-1) 2 15 Figure S3. Fourier transform infrared (FTIR) spectra of SNW % transmission Extinktion Wellenzahlen wavenumber /(cm-1) 15 Figure S4. Fourier transform infrared (FTIR) spectra of SNW-3. S6

7 % transmission Extinktion wavenumber Wellenzahlen / cm(cm-1) 15 Figure S5. Fourier transform infrared (FTIR) spectra of SNW %T Wellenzahlen (cm-1) 2 15 Figure S6. Fourier transform infrared (FTIR) spectra of SNW-1 after pyrolysis at 45 C. S7

8 Solid-state NMR spectroscopy Figure S7. Cross-polarization (CP) 13 C MAS natural abundance NMR spectrum of SNW-1. S8

9 Figure S8. Cross-polarization (CP) 15 N MAS natural abundance NMR spectrum of SNW-1. S9

10 Thermogravimetric analysis (TGA) weight / % temperature / C Figure S9. Thermogravimetric analysis of SNW-1 (blue), SNW-2 (red), SNW-3 (green) and SNW-4 (purple). S1

11 Scanning electron microscopy (SEM) Figure S1. Scanning electron micrograph of SNW-1. Figure S11. Scanning electron micrograph of SNW-2. S11

12 Figure S12. Scanning electron micrograph of SNW-3. Figure S13. Scanning electron micrograph of SNW-4. S12

13 Nitrogen sorption analysis Composition S BET [m 2 /g] PV [cm 3 /g] MPV 1 [cm 3 /g] MPV 2 [cm 3 /g] SNW SNW-1 (45 C) SNW SNW SNW Table S1. BET surface area (S BET ), pore volume (PV, calculated at p/p =.8), micropore volume (MPV 1, calculated at p/p =.1), NLDFT micropore volume (MPV 2 ) of the SNW materials. 25 adsorbed volume / cm -3 g -1, STP ,,1,2,3,4,5,6,7,8,9 1, Figure S14. Nitrogen sorption (filled symbols) and desorption (empty symbols) isotherms of SNW-1. p/p S13

14 14 12 adsorbed volume / cm 3 g -1, STP ,,1,2,3,4,5,6,7,8,9 1, Figure S15. Nitrogen sorption (filled symbols) and desorption (empty symbols) isotherms of SNW-2. p/p 3 adsorbed volume / cm 3 g -1, STP ,,1,2,3,4,5,6,7,8,9 1, p/p Figure S16. Nitrogen sorption (filled symbols) and desorption (empty symbols) isotherms of SNW-3. S14

15 16 14 adsorbed volume / cm 3 g -1, STP ,,1,2,3,4,5,6,7,8,9 1, Figure S17. Nitrogen sorption (filled symbols) and desorption (empty symbols) isotherms of SNW-4. p/p 2 18 adsorbed volume cm 3 /g, STP ,,1,2,3,4,5,6,7,8,9 1, Figure S18. Nitrogen sorption (filled symbols) and desorption (empty symbols) isotherms of SNW-1 after pyrolysis at 45 C. p/p S15

16 5 45 adsorbed volume cm 3 /g, STP ,5-4 -3,5-3 -2,5-2 -1,5-1 log(p/p ) Figure S19. Semi-logarithmic plot of the nitrogen sorption isotherms in the low pressure region of SNW-1 (blue), SNW-2 (red), SNW-3 (green), SNW-4 (purple) and SNW-1 after pyrolysis at 45 C (black).,1,9,8,7 dv(w) / cm 3 g -1 Å -1,6,5,4,3,2, pore with / Å Figure S2. NLDFT pore size distribution of SNW-1 (blue), SNW-2 (red), SNW-3 (green), SNW-4 (purple) and SNW-1 after pyrolysis at 45 C (black). Data calculated using the carbon slit pore model. S16

17 ,18,16,14 dv(w) / cm 3 g -1 Å -1,12,1,8,6,4, pore width / Å Figure S21. Horvarth-Kawazoe pore size distribution of SNW-1 (blue), SNW-2 (red), SNW- 3 (green) and SNW-4 (purple) and SNW-1 after pyrolysis at 45 C (black). References (1) Kotha, S.; Shah, V. R. Synthesis 28, 23, (2) Benett, A. E.; Rienstra, C. M.; Auger, M.; Lakshmi, K. V.; Griffin, R. G. J. Chem. Phys. 1995, 13, (3) Muntean, J. V.; Stock, L. M.; Botto, R. E. J. Magn. Reson. 1988, 76, (4) Morkombe, C. R.; Zilm, K. J. Magn. Reson. 23, 162, (5) Goward, G. R.; Schnell, I.; Brown, S.P.; Spiess, H. W.; Kim, H.-D.; Ishida, H. Magn. Reson. Chem. 21, 39, S5-S17. S17