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Electronic Supplementary Information

Cyclic (H2O)6 confined hexameric host-guest assemblies and

aerial CO2 fixation by electron-rich neutral urea/thiourea

scaffolds

Utsab Manna and Gopal Das*

Department of Chemistry, Indian Institute of Technology Guwahati,

Assam-781039, India

E-mail: gdas@iitg.ernet.in

Electronic Supplementary Material (ESI) for CrystEngComm.This journal is © The Royal Society of Chemistry 2018

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Scheme S1: Synthetic pathway for preparation of tris-oxyurea receptor L1 and tris-thiourea receptor L2.

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Characterization of receptor L1:

Figure S1: ESI-mass spectrum of tris-urea receptor L1.

Figure S2: FT-IR spectrum of receptor L1 recorded in KBr pellet.

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Figure S3: Integrated 1H-NMR spectrum (full as well as expanded) and interpretation of all hydrogen atoms

of free tripodal tris-urea receptor L1 in DMSO-d6 at 25ºC.

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Characterization of receptor L2:

Figure S4: ESI-mass spectrum of tris-thiourea receptor L2.

Figure S5: FT-IR spectrum of receptor L2 recorded in KBr pellet.

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Figure S6: Integrated 1H-NMR spectrum (full as well as expanded) and interpretation of all hydrogen atoms

of free tripodal tris-thiourea receptor L2 in DMSO-d6 at 25ºC.

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Characterization of complex 1a:

Figure S7: FT-IR spectrum of hexameric cyclic-water trapped fluoride complex 1a recorded in KBr pellet.

Figure S8: 1H NMR spectrum of hexameric cyclic-water trapped fluoride complex 1a in DMSO-d6 at 298 K.

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Figure S9. Powder X-ray diffraction: simulated pattern from the single-crystal X-ray of fluoride complex 1a (red), experimental pattern from the crystalline solid of complex 1a (black).

Figure S10: Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) curve of cyclic

water entrapped fluoride encapsulated complex 1a at a heating rate of 10 °C per min.

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Characterization of complex 1b:

Figure S11: FT-IR spectrum of dihydrogen-phosphate dimer encapsulated dimeric complex 1b recorded in KBr

pellet.

Figure S12: 1H NMR spectrum of dihydrogen-phosphate complex 1b in DMSO-d6 (Varian-600 MHz) at 298 K.

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Figure S13. Powder X-ray diffraction: simulated pattern from the single-crystal X-ray of dihydrogen-phosphate

complex 1b (red), experimental pattern from the crystalline solid of complex 1b (black).

Characterization of complex 2a:

Figure S14: FT-IR spectrum of unimolecular chloride encapsulated complex 2a recorded in KBr pellet.

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Figure S15: 1H NMR spectrum of chloride complex 2a in DMSO-d6 (Varian-600 MHz) at 298 K..

Figure S16. Powder X-ray diffraction: simulated pattern from the single-crystal X-ray of chloride complex 2a

(red), experimental pattern from the crystalline solid of complex 2a (black).

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Characterization of complex 2b:

Figure S17: FT-IR spectrum of unimolecular acetate encapsulated complex 2b recorded in KBr pellet.

Figure S18: Full and expanded 1H NMR spectrum of acetate complex 2b in DMSO-d6 (Varian-600 MHz) at

298 K.

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Characterization of complex 2c:

Figure S19: FT-IR spectrum of carbonate encapsulated dimeric complex 2b recorded in KBr pellet.

Figure S20: 1H NMR spectrum of complex 2b in DMSO-d6 (Varian-600 MHz) at 298 K

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Figure S21. Powder X-ray diffraction: simulated pattern from the single-crystal X-ray of carbonate complex 2b (red), experimental pattern from the crystalline solid of complex 2b (black).

Characterization of complex 2d:

Figure S22: FT-IR spectrum of divalent sulphate encapsulated dimeric complex 2c recorded in KBr pellet.

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Figure S23. 1H NMR spectrum of sulphate complex 2c in DMSO-d6 (Varian-600 MHz) at 298 K

Figure S24. Powder X-ray diffraction: simulated pattern from the single-crystal X-ray of sulphate complex 2c (red), experimental pattern from the crystalline solid of complex 2c (black).

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Solution state anion binding studies:

Figure S25: Expanded partial 1H NMR stack plot of L1 upon titration with standard n-TBAF in DMSO-d6.

.

Figure S26: Comparative expanded partial 1H NMR plots of free thiouurea receptor L2 (below), upon

qualitative addition of excess n-TBAF (middle) and excess TEAHCO3 (top).

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Figure S27: Expanded partial 1H NMR stack plot of L1 upon titration with standard n-TBAH2PO4 in DMSO-d6.

Figure S28: Change in chemical shift of urea -NHb resonance of L1 (10 mM) with increasing concentration of

standard H2PO4- solution (50 mM) in DMSO-d6 at 298 K.

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Figure S29: Expanded partial 1H NMR stack plot of L2 upon titration with standard n-TBACl in DMSO-d6.

Figure S30: Change in chemical shift of thiourea -NH resonances of L2 (10 mM) with increasing concentration

of standard Cl- solution (50 mM) in DMSO-d6 at 298 K and the corresponding Job’s plot.

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Figure S31: Expanded partial 1H NMR stack plot of L2 upon titration with standard (n-TBA)2SO4 in DMSO-d6.

Figure S32: Change in chemical shift of of thiourea -NH resonances of L2 (10 mM) with increasing

concentration of standard SO42- solution (50 mM) in DMSO-d6 at 298 K and the corresponding Job’s plot.

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Figure S33: Expanded partial 1H NMR stack plot of L2 upon titration with standard n-TBAOCOCH3 in DMSO-

d6.

Figure S34: Change in chemical shift of of thiourea -NH resonances of L2 (10 mM) with increasing

concentration of standard OCOCH3- solution (50 mM) in DMSO-d6 at 298 K and the corresponding Job’s plot.

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Figure S35: Change in chemical shift of -NHb resonances of L (10 mM) with increasing concentration of standard Cl- solution (50 mM) in DMSO-d6 (left) and the corresponding concentration plot of 1:1 and 2:1 complexation (right) obtained from WINEQNMR programme.

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Figure S36: Change in chemical shift of –NHa resonances of L (10 mM) with increasing concentration of standard SO4

2- solution (50 mM) in DMSO-d6 (left) and the corresponding concentration plot of 1:1 and 2:1 complexation (right) obtained from WINEQNMR programme.

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Figure S37: Change in chemical shift of –NHa resonances of L2 (10 mM) with increasing concentration of standard OCOCH3

- solution (50 mM) in DMSO-d6 (left) and the corresponding concentration plot of 1:1 and 2:1 complexation (right) obtained from WINEQNMR programme.

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Table S1. Hydrogen bonding distances (Å) and Bond angles (º) in the halide complexes 1 and 2:

Complex D−H∙∙∙A d(D∙∙∙H)/Å d(H∙∙∙A)/Å d(D∙∙∙A)/Å <D−H∙∙∙A/° Symmetry codesL1 N2-H2N∙∙∙O3 0.86 2.15 2.953(4) 155 x,y,z

N3-H3N∙∙∙O3 0.86 2.17 2.965(5) 153 x,y,zN4-H4N∙∙∙O1 0.86 2.18 2.935(4) 147 2-x,1-y,-zN5-H5N∙∙∙O1 0.86 2.12 2.921(4) 154 2-x,1-y,-zN6-H6N∙∙∙O2 0.86 2.04 2.863(3) 161 1-x,1-y,1-zN7-H7N∙∙∙O2 0.86 2.30 3.074(4) 150 1-x,1-y,1-z

L2 N3-H3N∙∙∙S2 0.86 2.59 3.439(4) 168 -1/2+x,1-y,zN7-H6N∙∙∙S1 0.86 2.49 3.331(5) 166 1/2+x,1-y,z

N11-H11N∙∙∙S4 0.86 2.76 3.455(4) 139 x,1+y,zN12-H12N∙∙∙S5 0.86 2.59 3.411(5) 160 -1/2+x,1-y,zN14-H14N∙∙∙S6 0.86 2.63 3.463(4) 162 1/2+x,1-y,z

1a O2-H1O∙∙∙O2 0.85 1.86 2.704(9) 177 -1/3+y,1/3-x+y,1/3-zO2-H2O∙∙∙O1 0.85 1.94 2.781(6) 171 x,y,zN2-H2N∙∙∙F1 0.86 2.14 2.916(5) 150 x,y,zN3-H3N∙∙∙F1 0.86 1.88 2.717(3) 163 x,y,z

1b N2-H2N∙∙∙O4 0.86 2.10 2.935(6) 164 x,y,zN3-H3N∙∙∙O2 0.86 2.06 2.884(6) 160 -x,-y,1-zN4-H4N∙∙∙O4 0.86 2.06 2.823(6) 147 x,y,zN5-H5N∙∙∙O5 0.86 2.32 3.134(6) 159 x,y,zN6-H6N∙∙∙O4 0.86 2.05 2.896(6) 168 x,y,zN7-H7N∙∙∙O7 0.86 2.07 2.924(6) 169 x,y,zO5-H5O∙∙∙O7 0.82 1.74 2.557(4) 177 1-x,-y,1-zC2-H2D∙∙∙O2 0.97 2.50 3.312(6) 142 -x,-y,1-z

2a N2-H2N∙∙∙Cl1 0.86 2.57 3.374(7) 155 -1+x,y,zN3-H3N∙∙∙Cl1 0.86 2.38 3.212(7) 164 -1+x,y,zN4-H4N∙∙∙Cl1 0.86 2.66 3.451 (7) 153 -1+x,y,zN5-H5N∙∙∙Cl1 0.86 2.37 3.226(7) 172 -1+x,y,zN6-H6N∙∙∙Cl1 0.86 2.59 3.400(7) 157 -1+x,y,zN7-H7N∙∙∙Cl1 0.86 2.40 3.249(8) 168 -1+x,y,z

2b N2-H2N∙∙∙O1 0.86 1.97 2.824(6)) 173 x,y,zN3-H3N∙∙∙O2 0.86 2.12 2.980(6) 173 x,y,zN4-H4N∙∙∙O2 0.86 2.56 3.321(6) 148 x,y,zN5-H5N∙∙∙O2 0.86 2.09 2.923(6) 162 x,y,zN6-H6N∙∙∙O1 0.86 2.24 2.960(6) 141 x,y,zN7-H7N∙∙∙O1 0.86 1.94 2.779(6) 166 x,y,z

2c N2-H2N∙∙∙O2B 0.86 2.04 2.890(12) 169 x,y,z

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N3-H3N∙∙∙O1B 0.86 2.11 2.946(13) 164 x,y,zN4-H4N∙∙∙O1B 0.86 2.13 2.928(11) 154 x,y,zN5-H5N∙∙∙O1B 0.86 2.35 3.008(12) 134 x,y,zN6-H6N∙∙∙O2B 0.86 2.12 2.910(13) 153 x,y,zN7-H7N∙∙∙O2B 0.86 2.09 2.907(12) 158 x,y,zN9-H9N∙∙∙O3B 0.86 2.15 2.996(16) 170 x,-1+y,z

N10-H10N∙∙∙O2B 0.86 2.19 2.981(14) 154 x,-1+y,zN11-H11N∙∙∙O3B 0.86 2.03 2.859(18) 160 x,-1+y,zN12-H12N∙∙∙O3B 0.86 2.34 3.104(14) 149 x,-1+y,zN13-H13N∙∙∙O3B 0.86 2.31 3.155(15) 166 x,-1+y,zN14-H14N∙∙∙O3B 0.86 2.13 2.916(12) 151 x,-1+y,z

C68-H68B∙∙∙S1 0.97 2.73 3.692(10) 171 1/2-x,-1/2+y,1/2+zC78-H78A∙∙∙S6 0.97 2.82 3.759(11) 163 x,y,z

2d N2-H2N∙∙∙O1A 0.86 2.40 3.131(13) 144 1/2-x,-1/2+y,-1/2+zN2-H2N∙∙∙O3A 0.86 2.32 3.104(13) 152 1/2-x,-1/2+y,-1/2+zN2-H2N∙∙∙O4B 0.86 2.13 2.964(9) 162 1/2-x,-1/2+y,-1/2+zN3-H3N∙∙∙O1A 0.86 2.16 2.961(12) 155 1/2-x,-1/2+y,-1/2+zN3-H3N∙∙∙O2B 0.86 2.22 2.999(9) 151 1/2-x,-1/2+y,-1/2+zN4-H4N∙∙∙O2A 0.86 2.44 3.175(11) 144 1/2-x,-1/2+y,-1/2+zN4-H4N∙∙∙O3A 0.86 2.60 3.294(11) 139 1/2-x,-1/2+y,-1/2+zN4-H4N∙∙∙O4B 0.86 2.06 2.917(9) 173 1/2-x,-1/2+y,-1/2+zN5-H5N∙∙∙O1B 0.86 2.22 2.949(8) 143 1/2-x,-1/2+y,-1/2+zN5-H5N∙∙∙O3A 0.86 2.04 2.881(13) 166 1/2-x,-1/2+y,-1/2+zN6-H6N∙∙∙O1A 0.86 2.15 2.960(13) 156 1/2-x,-1/2+y,-1/2+zN6-H6N∙∙∙O4B 0.86 2.11 2.942(9) 163 1/2-x,-1/2+y,-1/2+zN7-H7N∙∙∙O2A 0.86 2.08 2.923(11) 166 1/2-x,-1/2+y,-1/2+zN7-H7N∙∙∙O3B 0.86 2.24 2.971(7) 142 1/2-x,-1/2+y,-1/2+zN9-H9N∙∙∙O2B 0.86 2.30 3.076(8) 150 x,y,zN9-H9N∙∙∙O4A 0.86 2.07 2.912(11) 167 x,y,z

N10-H10N∙∙∙O1A 0.86 2.32 3.041(13) 134 x,y,zN10-H10N∙∙∙O3B 0.86 2.02 2.883(8) 177 x,y,zN11-H11N∙∙∙O1B 0.86 2.41 3.171(8) 147 x,y,zN11-H11N∙∙∙O3B 0.86 2.35 3.104(8) 146 x,y,zN11-H11N∙∙∙O4A 0.86 2.11 2.959(13) 167 x,y,zN12-H12N∙∙∙O1B 0.86 2.09 2.935(8) 165 x,y,zN12-H12N∙∙∙O2A 0.86 2.36 3.060(12) 138 x,y,zN13-H13N∙∙∙O1B 0.86 2.07 2.901(9) 161 x,y,zN13-H13N∙∙∙O4B 0.86 2.12 2.919(13) 155 x,y,zN14-H14N∙∙∙O2B 0.86 2.13 2.939(9) 157 x,y,zN14-H14N∙∙∙O3A 0.86 2.22 3.007(11) 151 x,y,z

C57-H57B∙∙∙S1 0.97 2.86 3.776(12) 157 x,y,zC71-H71B∙∙∙S5 0.97 2.84 3.748(7) 155 -x,-y,-1/2+z

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Figure S38. The scatter plot of N−H∙∙∙A angle vs. H∙∙∙A distance of the hydrogen bonds in (a) free receptor L1, (b) free receptor L2, (c) complex 1a, (d) complex 1b, (e) complex 2a, (f) complex 2b, (g) complex 2c and (h) complex 2d.