Electronic Supplementary Information

Encapsulation of Polyoxometalates in the Zr-based Metal

Organic Framework UiO-67

William Salomon,a Catherine Roch-Marchal,*a Pierre Mialane,a Paul Rouschmeyer,a Christian

Serre,a Mohamed Haouas,a Francis Taulelle,a Shu Yang,b Laurent Ruhlmannb and Anne Dolbecq*a

Electronic Supplementary Material (ESI) for Chemical Communications.This journal is © The Royal Society of Chemistry 2015

References of POM@MOF composites

MOF = MIL-100 and MIL-101Keggin-type POMs - Impregnation(a) G. Férey, C. Mellot-Draznieks, C. Serre, F. Millange, J. Dutour, S. Surblé and I. Margiolaki, Science, 2005, 309, 2040; (b) N. V. Maksimchuk, M. N. Timofeeva, M. S. Melgunov, A. N. Shmakov, Y. A. Chesalov, D. N. Dybtsev, V. P. Fedin and O. A. Kholdeeva, J. Catal. A, 2008, 257, 315; (c) N. V. Maksimchuk, K. A. Kovalenko, S. S. Arzumanov, Y. A. Chesalov, M. S. Melgunov, A. G. Stepanov, V. P. Fedin and O. A. Kholdeeva, Inorg. Chem., 2010, 49, 2920; (d) A. Micek-Ilnicka and B. Gil, Dalton Trans., 2012, 41, 12624; (e) L. Bromberg, Y. Diao, H. Wu, S. C. A. Speakman and T. A. Hatton, Chem. Mater., 2012, 24, 1664; (f) Z. Saedi, S. Tangestaninejad, M. Moghadam, V. Mirkhani and I. Mohammadpoor-Baltork, J. Coord. Chem. 2012, 65, 463; (g) C. M. Granadeiro, A. D. S. Barbosa, P. Silva, F. A. Almeida Paz, V. K. Saini, J. Pires, B. de Castro, S. S. Balula and L. Cunha-Silva, Applied Catal. A: General, 2013, 453, 316; (h) D. M. Fernandes, A. D. S. Barbosa, J. Pires, S. S. Balula and L. Cunha-Silva, ACS Appl. Mater. Interfaces, 2013, 5, 13382; (i) C. M. Granadeiro, A. D. S. Barbosa, S. Ribeiro, I. C. M. Santos, B. de Castro, L. Cunha-Silva and S. S. Balula, Catal. Sci. Technol, 2014, 4, 1416; (j) J. Zhu, M.-N. Shen, X.-C. Wang and M. Lu, ChemPlusChem. 2014, 79, 872.

Keggin-type POMs – In situ (a) J. Juan-Alcañiz, E. V. Ramos-Fernandez, U. Lafont, J. Gascon and F. Kapteijn , J. Catal., 2010, 269, 229; (b) R. Canioni, C. Roch-Marchal, F. Sécheresse, P. Horcajada, C. Serre, M. Hardi-Dan, G. Férey, J.-M. Grenèche, F. Lefebvre, J.-S. Chang, Y.-K. Hwang, O. Lebedev, S. Turner and G. Van Tendeloo, J. Mat. Chem., 2011, 21, 1226; (c) Y. Zhang, V. Degirmenci, C. Li and E. J. M. Hensen, ChemSusChem., 2011, 4, 59. (d) J. Juan- Alcañiz, M. G. Goesten, E. V. Ramos-Fernandez, J. Gascon and F. Kapteijn, New. J. Chem., 2012, 36, 977; (e) L. Bromberg, X. Su, and T. A. Hatton, ACS Appl. Mater. Interfaces, 2013, 5, 5468; (f) A.-X. Yan, S. Yao, Y.-G. Li, Z.-M. Zhang, Y. Lu, W.-L. Chen and E.-B. Wang, Chem. Eur. J. 2014, 20, 6927; (g) J. J.-A. Alcañiz, M. Goesten, A. Martinez-Joaristi, E. Stavitski, A. V. Petukhov, J. Gascon and F. Kapteijn, Chem. Commun., 2011, 47, 8578.

Peroxotungstate complexes [XW4O24]3- (X = P, B)(a) N. V. Maksimchuk, K. A. Kovalenko, S. S. Arzumanov, Y. A. Chesalov, M. S. Melgunov, A. G. Stepanov, V. P. Fedin and O. A. Kholdeeva, Inorg. Chem., 2010, 49, 2920; (b) I. C. M. S. Santos, S. S. Balula, M. M. Q. Simões, L. Cunha-Silva, M. G. P. M. S. Neves, B. de Castro, A. M. V. Cavaleiro and J. A. S. Cavaleiro, Catal. Today, 2013, 203, 87.

Sandwich-type POMs(a) C. M. Granadeiro, P. Silva, V. K. Saini, F. A. Almeida Paz, J. Pires, L. Cunha-Silva and S. S. Balula, Catal. Today, 2013, 218, 35; (b) S. S. Balula, C. M. Granadeiro, A. D. S. Barbosa, I. C. M. S. Santos and L. Cunha-Silva Catal. Today, 2013, 210, 142; (c) S. Ribeiro, C. M. Granadeiro, P. Silva, F. A. Almeida Paz, F. Fabrizi de Biani, L. Cunha-Silva and S. S. Balula, Catal. Sci. Technol., 2013, 3, 2404; (d) W. Salomon, F.-J. Yazigi, C. Roch-Marchal, P. Mialane, P. Horcajada, C. Serre, M. Haouas, F. Taulelle and A. Dolbecq, Dalton Trans., 2014, 43, 12698.

MOF = HKUST(a) C.-Y. Sun, S.-X. Liu, D.-D. Liang, K.-Z. Shao, Y.-H. Ren, and Z.-M. Su, J. Am. Chem. Soc., 2009, 131, 1883; (b) J. Song, Z. Luo, D. K. Britt, H. Furukawa, O. M. Yaghi, K. I.

Hardcastle, and C. L. Hill, J. Am. Chem. Soc., 2011, 133, 16839; (c) S. R. Bajpe, C. E. A. Kirschhock, A. Aerts, E. Breynaert, G. Absillis, T. N. Parac-Vogt, L. Giebeler and J. A. Martens, Chem. Eur. J. 2010, 16, 3926; (d) L. H. Wee, N. Janssens, S. R. Bajpe, C. E. A. Kirschhock and J. A. Martens, Catal. Today, 2011, 171, 275; (e) S. R. Bajpe, E. Breynaert, D. Mustafa, M. Jobbágy, A. Maes, J. A. Martens and C. E. A. Kirschhock, J. Mat. Chem. 2011, 21, 9768; (f) L. H. Wee, C. Wiktor, S. Turner, W. Vanderlinden, N. Janssens, S. R. Bajpe, K. Houthoofd, G. V. Tendeloo, S. De Feyter, C. E. A. Kirschhock, J. Am. Chem. Soc., 2012, 134, 10911; (g) N. Janssens, L. H. Wee, S. Bajpe, E. B. Breynaert, C. E. A. Kirschhock and J. A. Martens, Chem. Sci., 2012, 3, 1847; (h) Y. Liu, X. Yang, J. Mia, Q. Tang, S. Liu, Z. Shi and S. Liu, Chem. Commun., 2014, 50, 10023.

MOF = ZIF-8R. Li, X. Ren, J. Zhao, X. Feng, X. Jiang, X. Fan, Z. Lin, X. Li, C. Hu and B. Wang, J. Mater. Chem. A, 2014, 2, 2168.

Experimental section

Synthesis of UiO-67The synthetic protocol of UiO-67 was inspired by Guillerm et al.1 ZrCl4 (116 mg, 0.5mmol), biphenyl-dicarboxylic acid (121 mg, 0.5 mmol) and benzoic acid (1.83 g, 15 mmol, 30 equivalents) were dissolved in 10 mL of dimethylformamide (DMF) in a 23 mL polytetrafluoroethylene-lined stainless steel containers. Hydrochloric acid 37% (83 μL) was then added to the solution. All reactants were stirred briefly before heating. The mixture was heated to 120 °C over a period of 1 h, kept at 120 °C for 24 h, and allowed to cool down to room temperature. The solid was filtrated, washed with dry DMF and dry acetone and dried in an oven at 90°C overnight. Anal. Calc. for [Zr6O4(OH)5.4][C14H8O4]5.3•H2O•DMF0.4 (found): C 45.2 (45.2), H 2.58 (2.67), N 0.28 (0.24). The presence of chlorine has not been detected by EDX analysis therefore the linker deficiency has been compensated by hydroxo ligands in the formula. Final mass: 102 mg (yield 60% based on Zr).

Synthesis of POM@UiO-67 composite materialsZrCl4 (116 mg, 0.5 mmol), biphenyl-dicarboxylic acid (121 mg, 0.5 mmol), 1/6 equivalent of POM (8.33 10-5 mol) (240 mg for H3[PW12O40], 304 mg for TBA4H3[PW11O39] and 485 mg for TBA6[P2W18O62]) and benzoic acid (1.83 g, 15 mmol, 30 equivalents) were dissolved in 10 mL of dimethylformamide (DMF) in a 23 mL polytetrafluoroethylene-lined stainless steel containers. Hydrochloric acid 37% (83 μL) was then added to the solution. All reactants were stirred briefly before heating. The mixture was heated to 120 °C over a period of 1 h, kept at 120 °C for 24 h, and allowed to cool down to room temperature. The solid was filtrated and washed on the filtrating funnel with three times 15mL of dry DMF and three times 15mL of dry acetone and dried in an oven at 90°C overnight.

PW11Zr@UiO-67: Final mass: 131 mg (yield 57% based on Zr). Anal. Calcd. (found) for [Zr6O4(OH)4][C14H8O4]5.73[PW11O39Zr]0.18•16H2O (PW11Zr@UiO-67): C 33.90 (34.15), H 2.90 (2.06), Zr 19.83 (19.03), W 12.81 (12.46).

PW12@UiO-67: Final mass: 110 mg (yield 38% based on Zr). Anal. Calcd. (found) for [Zr6O4(OH)4][C14H8O4]5.37[PW12O40]0.42•16H2O (PW12@UiO-67): C 26.05 (26.26), H 2.29 (1.84), Zr 15.79 (13.86), W 26.73 (27.03).

P2W18@UiO-67: Final mass: 202 mg (yield 73% based on Zr). Anal. Calcd. (found) for [Zr6O4(OH)4.3][C14H8O4]5.1[P2W18O62]0.25•18H2O (P2W18@UiO-67) : C 25.83 (26.05), H 2.45 (1.88), Zr 16.49 (15.14), W 24.92 (24.69).

Physical methods. Infrared (IR) spectra were recorded on a Nicolet 30 ATR 6700 FT spectrometer. Powder diffraction data were obtained on a Bruker D5000 diffractometer using Cu radiation (1.54059 Å). EDX measurements were performed on a JEOL JSM 5800LV apparatus. N2 adsorption isotherms were obtained at 77 K using a BELsorp Mini (Bel, Japan). Prior to the analysis, approximately 30 mg of sample were evacuated at 90°C under primary vacuum overnight. Thermogravimetry analyses (TGA) were performed on a Mettler Toledo TGA/DSC 1, STARe System apparatus under oxygen flow (50 mL min−1) at a heating rate of 5°C min−1 up to 800°C

1 Vincent Guillerm, PhD Thesis, University of Versailles Saint Quentin en Yvelines, Versailles, France, 2011

NMR spectroscopy. 1H, 13C and 31P MAS NMR spectra were recorded on a Bruker AVANCE-500 spectrometer (Larmor frequencies of 500.133, 125.777 and 202.255 MHz, respectively) at 298 K using a 3.2 mm MAS probe. The following conditions were used for recording the 1H MAS NMR spectra: the length of 90° 1H pulse was 1.8 μs, and the delay time between scans was 3.5 s, which satisfied 5 × T1 condition. 8 scans were collected for each 1D 1H MAS NMR spectrum. 31P MAS NMR spectra with high power proton decoupling were recorded with or without cross-polarization (CP) denoted below as 31P CPMAS NMR and 31P MAS NMR. The following conditions were used for recording the spectra with CP both in 1D and in 2D 1H−31P heteronuclear correlation (HETCOR) NMR experiments: the proton radiofrequency (rf) field was 75 kHz (3.3 μs length of 90° 1H pulse), contact time was 3.5 ms at the Hartmann−Hahn matching condition of 54 kHz, the delay time between scans was 3 s. The single pulse excitation 31P MAS NMR spectra were recorded with 90° flip angle pulses of 2.2 μs duration and 7 s recycle delay, which satisfied the 5 × T1 condition. In these experiments a high power proton decoupling of 45 kHz rf field was used only during the acquisition time. A 1024 scans were collected for each 1D 31P CPMAS NMR and 31P MAS NMR spectrum). For 2D CPMAS 1H−31P HETCOR NMR experiments a total of 16 t1 increments with 512 scans each were collected. The experimental parameters for the 13C CPMAS NMR experiments were 1.5 s pulse delay and 2 ms contact time. The spinning rate was 10 kHz for 1D 31P MAS NMR and 13C CPMAS NMR experiments, while for 1D 1H MAS NMR and 2D 1H-31P CPMAS HETCOR NMR experiments 20 kHz spin rate was employed. 1H and 13C chemical shifts were referenced with respect to TMS, whereas 31P chemical shifts to 85% H3PO4, as external standards, respectively, with accuracy of ± 0.5 ppm.

ElectrochemistryCyclovoltammograms were recorded at room temperature with an Autolab PGSTAT30 potentiostat (Eco Chemie, Holland) driven by a GPSE software running on a personal computer using a conventional three electrode set-up. The working electrode was basal plane pyrolytic graphite disk (PG, Pine, 5 mm Ø) or glassy carbon electrode (3 mm Ø), the counter electrode was platinum wire, and the reference electrode was a saturated calomel electrode (SCE) connected through a salt bridge. The working cell was surrounded by a grounded Faraday cage and all studies were carried out at room temperature and under a argon flow.Ultra-pure water (Millipore, 18.2 MΩ cm, 25°C) was used to prepare all electrolyte solutions. For electrochemical measurements was used a H2SO4/Na2SO4 buffer solution (pH = 2.5), which was prepared by mixing suitable volumes of 0.5 mol dm−3 Na2SO4 solution with H2SO4 solution. The solutions were deaerated thoroughly by bubbling argon through the solution and kept under argon atmosphere during the whole experiment.Prior to being used, the PG electrode was cleaned which consisted on polishing it on a microcloth polishing pad with aluminium oxide (0.3 μm particle size). Finally, the electrode was washed with ethanol and ultra-pure water and sonicated in the later in an ultrasonic bath for 5 min. Electrode modification consisted in depositing an appropriate amount of powder of each material on the PG surface.

Figure S1. X-Ray diffraction patterns of UiO-67 and POM@UiO-67 composites.

Figure S2. TGA measurements of UiO-67 and POM@UiO-67 composites.

2-Theta - Scale3 10 20

UIO-67

PW11Zr@UIO-67

PW12@UIO-67

P2W18@UIO-67

30

40

50

60

70

80

90

100

20 120 220 320 420 520 620 720 820

Temperature (°C)

PW11Zr@UIO-67

PW12@UIO-67

P2W18@UIO-67

UIO-67

Table S1. Comparison between calculated and experimental weight losses.

Water Organic ligand Oxide

Calc. Exp Calc. Exp Calc. Exp

UiO-67 7.3 7.0 62.5 58.8 34.9 34.2

PW11Zr 10.0 7.9 48.4 46.0 43.4 46.1

PW12 8.3 5.5 37.2 35.0 55.9 59.5

P2W18 9.8 5.0 36.9 34.5 54.8 60.5

Figure S3. N2 adsorption/desorption isotherm (77K, P/P0 = 1 atm.) of UiO-67 and the POM@UiO-67 composites.

0

100

200

300

400

500

600

0 0.2 0.4 0.6 0.8 1

V a/c

m3 (

STP)

g-1

p/p0

PW11Zr@UIO-67

UIO-67

P2W18@UIO-67

PW12@UIO-67

Table S2. Specific surface area, total pore volume and maxima for pore size distribution.

S BET

(m2 g-1)

Total pore volume (cm3 g-1)

at P/P0 = 0.96

UiO-67 2400 0.91

PW11Zr@UiO-67 1400 0.53

PW12@UiO-67 1390 0.57

P2W18@UiO-67 1100 0.49

Figure S4. 1H MAS NMR spectra of UiO-67 and POM@UiO-67 composites.

Figure S5. 13C{1H} CPMAS NMR spectra of UiO-67 and POM@UiO-67 composites.

Figure S6. Solid-state NMR spectra of PW12@UiO-67: (a) 31P{1H} CPMAS; (b) 1H-31P HETCOR; (c) 1H MAS.

Figure S7. Solid-state NMR spectra of PW11Zr@UiO-67: (a) 31P{1H} CPMAS; (b) 1H-31P HETCOR; (c) 1H MAS.

Figure S8. 31P NMR spectra of a) PW11 in DMF and b) PW11+ 6eq ZrCl4 in DMF.

b)

a)

/ppm

-12.3 ppm

-13.2 ppm

Figure S9. Cyclic voltammograms of PW12 in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions at different scan rates from 0.025 to 1.000 Vs-1. Inset: plots of Ipc vs. v1/2 for peaks I and II (WVI/V redox couples).

Figure S10. Cyclic voltammograms of PW12@UiO-67 immobilized at a PG electrode in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions at different scan rates from 0.025 to 1.000 Vs-1. Inset: plots of Ipc vs. v for peaks I and II (WVI/V redox couples).

Figure S11. Cyclic voltammograms of P2W18 immobilized at a PG electrode in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions at different scan rates from 0.025 to 1.000 Vs-1. Inset: plots of Ipc vs. v for peaks I, II and III (WVI/V redox couples).

Figure S12. Cyclic voltammograms of PW11 immobilized at a PG electrode in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions at different scan rates from 0.025 to 1.000 Vs-1. Inset: plots of Ipc vs. v for peaks I to IV (WVI/V redox couples).

Figure S13. Cyclic voltammograms of PW11Zr@UiO-67 immobilized at a PG electrode in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions at different scan rates from 0.025 to 1.000 Vs-1. Inset: plots of Ipc vs. v for peaks I and II (WVI/V redox couples).

Figure S14. Cyclic voltammograms of P2W18 + UiO-67 (mechanical mixing) immobilized at a PG electrode in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions at different scan rates from 0.025 to 1.000 Vs-1. Inset: plots of Ipc vs. v for peaks I, II and III (WVI/V redox couples).

Figure S15. Cyclic voltammograms of PW11 + UiO-67 (mechanical mixing) immobilized at a PG electrode in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions at different scan rates from 0.025 to 1.000 Vs-1. Inset: plots of Ipc vs. v for peaks I, II and IV (WVI/V redox couples).

Figure S16. Cyclic voltammogram of PW12 + UiO-67 (mechanical mixing) immobilized at a PG electrode in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions. V = 1.000 Vs-1. Rapid desorption of PW12 was observed because PW12 was soluble in aqueous solution.

Table S3. Formal reduction potential (EO’) for POMs, POM@UiO-67 and POM+UiO-67 composites (WVI/V redox couples) immobilized at a PG electrode measured in pH 2.5 H2SO4/Na2SO4 0.5 M buffer solutions.

Compounds E(O’) vs. SCE / mV

W reduction

PW12 -249 -457 -732 -830

PW12@UiO-67 -279 -540 -736 -840

PW12+UiO-67a -250 -459 -734 -832

PW11 -450 -560 -694 -830

PW11Zr@UiO-67 -713 -885

PW11+UiO-67a -458 -564 -690 -827

P2W18 -349 -588 -811

P2W18@UiO-67 -175 -564 -820

P2W18+UiO-67a -359 -564 -828

a Mechanical mixing POMs and UiO-67.