Supporting Information

Transcription

1 Supporting Information Wiley-VCH Weinheim, Germany

2 Supporting Information Amine-grafting on Coordinatively Unsaturated Metal Centers of MOFs: Catalytic and Metal Incorporation Consequences Young Kyu Hwang 1, Do-Young Hong 1, Jong-San Chang 1*, Sung Hwa Jhung 2, You- Kyong Seo 1, Jinheung Kim 3, Alexandre Vimont 4, Marco Daturi 4, Christian Serre 5, and Gérard Férey 5* 1 Catalysis Center for Molecular Engineering, Korea Research Institute of Chemical Technology (KRICT), P.O. Box 107, Yusung, Taejon (Korea) Fax: (+82) , jschang@krict.re.kr 2 Department of Chemistry, Kyungpook ational University, Daegu (Korea) 3 Department of Chemistry, Division of ano Sciences, Ewha Womans University, Seoul (Korea) 4 Laboratoire Catalyse et Spectrochimie, UMR 6505, CRS/ESICAE et Université de Caen Basse-ormandie, 6, boulevard Maréchal Juin, Caen Cedex (France) 5 Institut Lavoisier, UMR 8180, Université de Versailles Saint Quentin, 45 avenue des Etats- Unis, Versailles Cedex (France), ferey@chimie.uvsq.fr

3 Experimental Section 1. Synthesis of MIL-101 MIL-101 was initially prepared from hydrothermal reaction of terephthalic acid (166 mg at 1 mmol) with Cr(O 3 ). 3 9H 2 O (400 mg at 1 mmol), HF (0.2 ml at 1 mmol), and H 2 O (4.8 ml at 265 mmol) at 493 K for 8 h. This reaction produced a highly crystallized green powder of the chromium terephthalate with formula Cr 3 F(H 2 O) 2 O[(O 2 C)-C 6 H 4 -(CO 2 )]. 3 nh 2 O (where n is 25), based on chemical analysis. As mentioned previously, a significant amount of nonreacted terephthalic acid is present both outside and within the pores of MIL-101. [1,2] To avoid this, the as-synthesized MIL-101 was further purified by the following two-step processes using hot ethanol and aqueous H 4 F solutions. The crystalline MIL-101 product in the solution was doubly filtered off using two glass filters with a pore size between 40 and 100 μm to remove the free terephthalic acid. Then a solvothermal treatment was sequentially performed using ethanol (95 % EtOH with 5 % water) at 353 K for 24 h. The resulting solid was soaked in 1 M of H 4 F solution at 70 o C for 24 h and immediately filtered, washed with hot water. The solid was finally dried overnight at 423 K under air atmosphere. 2. Amine-group functionalization in various molecular sieves Various amine-functionalized MIL-101 (Cr) were prepared according to the following process. In a typical procedure, sample (0.5 g) dehydrated at 423 K for 12 h was suspended in anhydrous toluene (30 ml). To this suspension, an appropriate amount (0.75 mmol) of 3- aminopropyltrimethoxysilane (APS), ethylenediamine (ED), and diethylentriamine (DETA) was added and the mixture was stirred under reflux for 12 h. The product was recovered by filtration and washed with de-ionized water/ethanol, and then dried at room temperature for amine-functionalized MIL-101. For example, ED-MIL-101 denotes the MIL-101 grafted with ED. The content of amine group was crossly examined by the elemental analysis and thermal gravimetry analyses. For comparison, aminopropyltrimethoxysilane (APS) was immobilized on calcined mesoporous silica SBA-15 in a similar manner. Mesoporous silica SBA-15 (S BET = 780 m 2 /g and V pore = 1.16 ml/g) was prepared by literature procedure. 3 In fact, it was rather difficult to obtain the APS-MIL-101 catalyst with reproducible activity because its activity was subtly altered even using the same grafting condition. The less reproducibility in APS-MIL-101 than ED-MIL-101 might be due to the fact that both amine and methoxy

4 groups in the APS molecule can competitively play a role as possible coordination sites to CUS Cr(III). 3. Encapsulation of noble metals in amine-grafted MIL-101 For precious metal incorporation, 1.0 g of ED-MIL-101(0.33) was mixed with de-ionized water containing 1.0 wt. % of PdCl 2, H 2 PtCl 6, and HAuCl 4 at ph~3 for 6 h. Because of the electrostatic interaction between cationic H + 3 group and anionic metal species in acidic condition, H MIL-101 having strongly captured metal ions was formed within a mixing of 60 min. The solid was settled down and filtered with ethanol and de-ionized water. The resulting M-H + 3 -MIL-101 (M = PdCl 2-4, PtCl 2-6, and AuCl - 4 ) samples were reduced separately by sodium borohydride (abh 4, 0.07g) dissolved in 10 ml ethanol at 273 K for 2 h to yield M-H 2 -MIL-101(0.33) (M=Pd, Pt, and Au). The Pd-APS-SBA-15 was followed the same procedure. For the comparison study, PdCl 2 was simple impregnated on the vacuum dried MIL-101 crystals. The mass loadings of the hybrid crystals by palladium (0.95 wt% for Pd/ED-MIL-101 and 0.93 wt% for Pd/APS-MIL-101, respectively), platinum (0.94 wt%), and gold (0.96 wt%) precursors were estimated by inductively coupled plasma (ICP) measurements. 4. Characterization Powder X-ray diffraction patterns of the as-prepared and amine functionalized MIL-101 samples were obtained by a Rigaku diffractormeter (D/MAX IIIB, 2kW) using i-filtered Cu Kα-radiation (40 kv, 30 ma, λ = A ) and a graphite crystal monochromator. The crystal size and morphology were examined using a scanning electron microscope (SEM: JEOL JSM-840A). For IR analyses, samples were pressed (107 Pa) into self-supported discs (2 cm 2 area, 7-10 mg cm -2 ). They were placed in a quartz cell equipped with KBr windows. A movable quartz sample holder permits the adjustment of the pellet in the infrared beam for spectra acquisition and to displace it into a furnace at the top of the cell for thermal treatments. The cell was connected to a vacuum line for evacuation, calcination steps (P residual = Pa) and for the introduction of CO into the infrared cell. Spectra were recorded at room temperature. In CO adsorption experiments, the temperature of the pellet was decreased to about 100 K by cooling the sample holder with liquid 2 after quenching the sample from the thermal treatment temperature. The addition of accurately known increments of CO probe molecules in the cell (a typical increment corresponds to 100 µmoles of CO per gram of

5 material) was possible via a calibrated volume (1.75 cm 3 ) connected to a pressure gauge for the control of the probe pressure ( Pa range). The CO pressure inside the IR cell was controlled by another pressure gauge ( Pa range). Transmission IR spectra were recorded in the cm -1 range, at 4 cm -1 resolution, on a icolet exus spectrometer equipped with an extended KBr beam splitting device and a mercury cadmium telluride (MCT) cryodetector. The carbon monoxide was obtained from Air Liquide (Alphagaz, France; % purity). itrogen elementary analyses (EA) were performed on a Heraeus CHS elemental analyzer. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed with TA instruments models, TGA 2950 with a 10 K/min in 2 atmosphere. The BET surface area measurements were performed with 2 adsorptiondesorption isotherms at liquid nitrogen temperature (77K) after dehydration under vacuum at 423 K for 12h using Micromeritics Tristar The specific surface areas were evaluated using the Brunauer-Emmett-Teller (BET) method in the p/p 0 range Pore size distribution curves were calculated using the adsorption branch of the isotherms and the Barrett-Joyner-Halenda (BJH) method, and pore sizes were obtained from the peak positions of the distribution curves. The pore volume was taken by a single point method at p/p 0 = Catalytic Measurements 5.1. Knoevenagel Condensation Before the reaction, the amine-functionalized materials were treated at 423 K for 12 h under vacuum to remove the residue water in the sample. In a typical experiment of the Knoevenagel condensation, two reactants such as benzaldehyde (BZA, 10 mmol) and ethyl cyanoacetate (ECA, 10 mmol) were mixed in 25 ml of cyclohexane as a solvent and heated to the set temperature, and then 20 mg of the dried catalyst was rapidly added into the reactor. All the catalytic reactions were carried out under 2 in a glass flask that was equipped with a reflux condenser and a magnetic stirrer. The reactor was placed in a thermostatic oil bath. After the reaction, the catalyst was separated by filtration. The products were analyzed using a Donam gas chromatograph (GC) equipped with a DB-WAX capillary column and a flame ionization detector. The conversions were calculated based on n-dodecane as an internals standard Heck Coupling Reaction

6 Pd-loaded amine-grafted MIL-101 was treated at 383K for 12 h before reaction. Reactions were carried out in a 200 ml of 2-neck flask reactor with reflux condenser. Equimolar amounts (15 mmol) of acrylic acid and triethylamine, 10 mmol of iodobenzene and the catalyst (50 mg, corresponding to 0.05 mol% Pd with respect to the reagents) were added to the 25ml,-Dimethylacetamide as a solvent and the mixture was stirred at 393 K. Samples of 0.1 ml were withdrawn periodically by syringe, and analyzed by a gas chromatograph equipped with a flame ionization detector and a capillary column, DB WAX. For the comparison, palladium on carbon (1.09 wt% Pd, S BET = 950 m 2 /g, Sigma-Aldrich) was used for the Heck reaction. 6. Recyclability Tests of Catalysts At the end of each catalytic reaction such as the Knoevenagel condensation, the catalyst was isolated from the reaction solution, dried at 423 K, and then reused in the second run of each reaction. The initial activity of the catalyst was also obtained in the second run, showing that the framework of the catalyst may remain intact during the catalytic cycles. The catalyst remained effective for up to 3 cycles for reactions (Fig. S5). Further proof was obtained with a separation experiment. After removal of the catalyst by filteration, no further reactivity was exhibited in the filtrate. The catalyst used in the second run was also analyzed by XRD, but no significant change was observed. Reference 1. G. Férey, C. Mellot-Draznieks, C. Serre, F. Millange, J. Dutour, S. Surblé, and I. Margiolaki, Science 2005, 309, S. Bourrellya, C. Serre, A. Vimont, M. Daturi, J.-S. Chang, D. -Y. Hong, Y. K. Hwang, L. Hamon, G. De Weireld, G. Férey, and P. L. Llewellyn, Langmuir accepted.. 3. J. M. Kim, Y. Sakamoto, Y. K. Hwang Y. -U. Kwon, O. Terasaki, S. -E. Park, and G. D. Stucky, J. Phys. Chem. B, 2002, 106, 2552.

7 (a) O OH H O H RO + Si RO OR H H - 3ROH O Si O O H H 서식있음 : 글꼴색 : 자동, ( 한글 ) 한국어 서식있음 : 글꼴 : ( 영어 ) Times ew Roman Mesoporous silica 서식있음 : 글꼴 : 10 pt, 굵게 (b) CU CU CU F,O CU + 서식있음 : 글꼴색 : 자동, ( 한글 ) 한국어 CU CU SBU of MIL-101 서식있음 : 글꼴 : 10 pt, 굵게 Figure S1. Schematic view of functionalization of mesoporous silica and MIL-101: (a) functionalization of mesoporous silica wall by alcoholysis of surface hydroxyl group and alkoxides of aminopropylsilane and (b) a strategy for surface functionalization of MIL-101 through selective grafting of chelating ligands onto coordinatively unsaturated chromium sites.

8 Intensity (cps) (d) (c) (b) (a) theta (deg.) Figure S2. XRD patterns of as-synthesized and surface immobilized MIL- 101: (a) MIL-101, (b) ED-MIL-101, (c) APS-MIL-101, and (d) DETA-MIL-101 after vacuum treatment 423 K for 12h.

9 (a) 서식있음 : 글꼴색 : 자동, ( 한글 ) 한국어 ED 0.67 서식있음 : 글꼴색 : 자동, ED 0.33 ( 한글 ) 한국어 Intensity of the ν(ch) bands (K) (b) Abs. ED 0.33 ED 0.67 서식있음 : 글꼴색 : 자동, ( 한글 ) 한국어 1 (1) (2) (3) (4) (5) (cm -1 ) (cm -1 ) 2500 Figure S3: Thermal stability of grafted samples under vacuum, followed by FT-IR: (a) Intensity of the ν(ch) stretching mode of ED groups versus the temperature of evacuation, (b) IR spectra of ED-MIL-101(0.33) (left) and ED-MIL-101(2/3) (right) outgassed under vacuum (10-4 Pa) during 15 minutes at room temperature (1), 373 K (2), 433 K (3), 473 K (4), 523 K (5).

10 100 Conversion of BZA (%) MIL-101 ED-MIL-101 ED-MIL-101(D) Reaction time (h) Figure S4. Catalytic activities of MIL-101, ED-MIL-101, and ED-MIL- 101(D) in Knoevenagel condensation with benzaldehyde (BZA) and ethylcyanoacetate. Reaction was carried out with 1.00 mmol of benzaldehyde, 1.00 mol of ethylcyanoacetate, 20 mg of catalytst in 25 ml of cyclohexane at 80 o C.

11 100 Conversion of M (%) Second run Third run First run Reaction time (min) Figure S5. The recyclability test of ED-MIL-101 in Knoevenagel condensation with benzaldehyde (BZA) and malononitrile (M). Reaction was carried out with 10 mmol of BAZ and 10 mmol of M, 50 mg of catalyst in 25ml of toluene at 353 K.

12 O R 1 R 2 + Y C R 1 R 2 Y C + H 2 O 100 Yield of product (%) a b c Reaction time (h) Figure S6. Product yields as a function of reaction time in the Knoevenagel condensation over ED-MIL-101 with various substrates. (a) R 1 = C 6 H 5 and R 2 = H, (b) R 1 = C 4 H 9 and R 2 = CH 3, and (c) R 1 = C 6 H 5 and R 2 = C 6 H 5. Reaction was carried out with 1.0 mmol of carbonyl compounds, 1.0 mol of malonitrile, and 50 mg of catalyst in 25 ml of toluene at 353 K.

13 80000 Intensity (cps) (d) (c) (b) 0 (a) theta (deg.) Figure S7. XRD patterns of as-synthesized and precious metal encapsulated H 2 -MIL-101. (a) MIL-101, (b) Au/APS-MIL-101, (c) Pt/APS-MIL-101, (d) Pd/APS-MIL-101.

14 Figure S8. TEM images of as-synthesized MIL-101 and precious metal immobilized ED- MIL-101. (a) as-synthesized MIL-101, (b) Pd/ED-MIL-101, (c) Au/ED-MIL-101, (d) Pt/ED- MIL-101, (e) Pd- impregnated MIL-101 and (f) Pd/APS-SBA-15. Insets are EDX profiles of impregnated precious metal nanoparticles.