PtAu bimetallic nanocatalyst for selective hydrogenation ...

Electronic Supplementary Material

PtAu bimetallic nanocatalyst for selective hydrogenation of alkenes over aryl halides Le Guo1,§, Junjie Mao3,§, Shuangxi Guo1, Qi Zhang1, Shuangfei Cai2 (), and Wei He1 ()

1 School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China 2 CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety, Center of Materials Science and Optoelectronics Engineering, CAS center for

Excellence in Nanoscience, National Center for Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100190, China 3 Center of Single-Atom, Clusters and Nanomaterials (CAN), Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory

of Molecule-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China § Le Guo and Junjie Mao contributed equally to this work. Supporting information to https://doi.org/10.1007/s12274-019-2416-6

TABLE OF CONTENTS 1 General Information 2 Syntheses of Supported Nanocrystal Catalysts 3 Screening of Catalysts using 1b 4 Substrate Scope Study 5 Asymmetric Hydrogenation of 1b 6 References 7 Appendix: 1H and 13C NMR Spectra of Related products.

1 General Information

1.1 Materials

All the chemicals used in this work were of analytical grade unless otherwise noted and used without purification. Column chromatography was performed with silica gel (200-300 mesh).

1.2 Instrumentation

Transmission electron microscopy (TEM) images were acquired with a Hitachi High-Tech HT7700 electron microscope (Hitachi High- Technologies Corporation, Tokyo, Japan) equipped with an energy dispersive X-ray (EDX) system. TEM specimens were prepared via the following procedure: the samples were dispersed in cyclohexane with the aid of 10 min ultrasonic vibration. Then a drop of the solution was transferred onto a standard holey carbon-covered-copper TEM micro grid.

High-resolution transmission electron microscopy (HRTEM) images and high-angle annular dark-field scanning TEM (HAADF-STEM) images were collected with a FEI Tecnai G2 F20 U-TWIN HRTEM.

FT-IR spectra were recorded on PerkinElmer Spectrum One FT-IR spectrometer in the transmission mode using CaF2. X-ray photoelectron spectra (XPS) were measured using a X-ray photoelectron spectrometer (Thermo Fisher ESCALAB 250Xi). Binding

energies (BE) were calibrated by setting the measured BE of C 1s to 284.8 eV. Powder X-ray diffraction (XRD) patterns obtained in this work were recorded with a Bruker D8-advance X-ray powder diffractometer

with monochromatized CuK radiation ( = 1.5406 Å). The metal ion content was measured by the inductively coupled plasma (ICP). 1H and 13C NMR spectra were recorded on a Bruker Avance 400 MHz Spectrometer with a 5 mm PABBO BB-1H/D Z-GRD Z108618/0394

multinuclear Probe at 298 K. High Resolution Mass Spectra (HRMS) of compounds were recorded with a Fourier Transform Ion Cyclotron Resonance Mass

Spectrometer (Bruker Apex IV). GC-MS data was performed on Shimadzu GCMS-QP2010SE gas chromatograph mass sepecrometer equipped with a capillary column

(Rtx-Wax, 30 m × 0.25 μm × 0.25 mm). Parameters were as follows for GC: initial oven temperature, 50 °C, 1 min; ramp, 10 °C/min; final temperature, 250 °C; final time, 15 min; injector temperature, 200 °C. Parameters were as follows for MS: EI ion source temperature, 200 °C, interface temperature, 250 °C.

2 Syntheses of Supported Nanocrystal Catalyts Note: To ensure user friendly and easily reproducible syntheses of the catalysts in other laboratories, the following synthetic methods have been tested and validated by multiple researchers of different skill levels.

Address correspondence to Shuangfei Cai, [email protected], Wei He, [email protected]

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2.1 Synthesis of and Characterization of NCs

Synthesis of Pd NCs: 10 mL of octadecylamine (ODA) was added into 50 mL of beaker. The resulting solution was heated up to 120 °C. Then, 20 mg of Pd(acac)2 (0.066 mmol) was added. After the reactants were dissolved, the mixture was heated up to 180 °C. The mixture was magnetically stirred for 10 min at this temperature before it was cooled down to room temperature. The as-obtained Pd NCs were washed with ethanol (10 mL) for 3 times and subsequently dispersed in cyclohexane for future use.

Synthesis of Au NCs: 10 mL of octadecylamine (ODA) was added into 50 mL of beaker. The resulting solution was heated up to 120 °C. Then, 27 mg of HAuCl4∙4H2O (0.066 mmol) was added. After the reactants were dissolved, the system was heated up to 150 oC. The mixture was magnetically stirred for 10 min at this temperature before it was cooled down to room temperature. The obtained NCs were washed with ethanol (10 mL) for 3 times and subsequently dispersed in cyclohexane for future use.

Synthesis of Pt NCs: 10 mL of octadecylamine (ODA) was added into 50 mL of beaker. The resulting solution was heated up to 120 °C. Then, 26 mg of Pt(acac)2 (0.066 mmol) was added. After the reactants were dissolved, the system was heated up to 220 °C. The mixture was magnetically stirred for 10 min at this temperature before it was cooled down to room temperature. The obtained NCs were washed with ethanol (10 mL) for 3 times and subsequently dispersed in cyclohexane for future use.

Synthesis of MxAuy (M = Pd, Pt; x, y = 1, 3, 5) NCs: 10 mL of octadecylamine (ODA) was added into 50 mL of beaker. The resulting solution was heated up to 120 °C. Then, Pd(acac)2 or Pt(acac)2 and HAuCl4∙4H2O at the nominal ratio were added (For example, for the synthesis of Pt1Au1 bimetallic NCs, 26 mg Pt(acac)2 and 27 mg of HAuCl4∙4H2O were used). After the reactants were dissolved, the mixture was heated up to 180 °C. The mixture was magnetically stirred for 10 min at this temperature before it was cooled down to room temperature. The as-obtained MxAuy NCs were washed with ethanol (10 mL) for 3 times and subsequently dispersed in cyclohexane for future use.

Larger Scale synthesis of Pt1Au1 NCs: 100 mL of octadecylamine (ODA) was added into a 250 mL beaker. The resulting solution was heated up to 120 °C. Then, 260 mg Pt(acac)2 and 270 mg of HAuCl4∙4H2O were added. After the reactants were dissolved, the mixture was heated up to 180 °C. The mixture was magnetically stirred for 10 min at this temperature before it was cooled down to room temperature. The as-obtained MxAuy NCs were split into five fractions and individually centrifuged and washed with ethanol (20 mL) for 3 times. The as-obtained NCs were combined and dispersed in cyclohexane for impregnation (see item 4.1)

Characterization of the as-prepared NCs: The detailed characterization of Pt, Au and PtxAuy (x, y = 1, 3, 5) was summarized in Figure S1. Figures S1 display the TEM images and size distributions of the as-prepared Pt, Au and PtxAuy (x, y = 1, 3, 5) NCs. The Pt NCs are characteristic of random-shaped stones while Au NCs and PtxAuy (x, y = 1, 3, 5) bimetallic NCs are spherical particles. All the NCs are of very similar average size (9.0 ~ 10.0 nm) with narrow size distribution. The powder X-ray diffraction (XRD) patterns further verified the formation of PtAu bimetallic NCs, wherein the characteristic peaks of Pt and Au NCs disappeared while new Bragg reflections was observed. As Pt content increases, the diffraction peaks continuously shift to higher 2θ degrees

Figure S1 TEM images and size distribution as well as XRD patterns of the as-prepared Pt, Au and PtxAuy (x, y = 1, 3, 5) NCs (scale bar = 50 nm).

Similar observations were made with the Pd and PdxAuy (x, y = 1, 3, 5) NCs through related TEM images and XRD patterns (Figure S2). The as-prepared Pd NCs are composed of wormlike particles while Pd5Au1 NCs consist of wormlike and near spherical particles. The average diameter of the spherical particles was 6.8 nm. Other samples show spherical morphology with average diameter 7.2 to 7.8 nm.

2.2 Preparation and Characterization of Supported Catalysts

Typical procedure: The corresponding PtxMy NCs (50 mg) were dispersed in 100 mL of cyclohexane in a 250 mL beaker. To this beaker was

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added active carbon (950 mg). The mixture was stirred at room temperature for 48 h. The solid was first obtained by filtration and then washed with cyclohexane (20 mL) three times.

To remove the capping agent we followed a procedure[2] reported by Yang et al. Thus, the obtained PtxMy/C was treated with butylamine at a concentration of 0.5 mg-catalyst/mL. The mixture was kept under stirring for 3 days and then collected using a centrifuge at a rate of 5000 rpm for 5 min. The precipitate was re-dispersed in 10 mL methanol by sonicating for 15 min and then separated by centrifugation. This procedure was repeated three times. The final samples were finally obtained by drying in air and stored on bench for future use.

Characterization of the as-prepared PtxMy/C: As an example, the detailed characterization of the fresh Pt1Au1/C was summarized in Figure S3.

Figure S2 TEM images and size distribution as well as XRD patterns of the as-prepared Pd and PdxAuy (x, y = 1, 3, 5) NCs.

Figure S3 Characterization of the as-prepared Pt1Au1/C: (a) representative TEM image, (b) HRTEM image, (c) enlarged HRTEM image and (d) HAADF-STEM image.

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3 Screening of Catalysts using 1b

3.1 Synthesis of Substrate 1b

The synthesis of substrate 1b followed a slightly modified procedure reported in the literature[1] (Scheme S1).

Scheme S1 Synthetic route for substrate 1b.

Compound S2: The 1-bromo-2-nitrobenzene S1 (2.02 g, 10 mmol) was placed in a two-necked round-bottomed flask fitted with a gas inlet (N2) and rubber septum. The flask was purged several times with N2 before adding dry THF (35 ~ 40 mL) and cooling to between -40 and -45 °C. The Grignard reagent (3 eq., 30 mmol) was then added to the THF solution and stirring continued for a further 30 min to 1 h. Saturated ammonium chloride solution was added to the reaction mixture (at ca. -40 °C) before allowing the mixture to warm to room temperature. The mixture was thoroughly extracted with diethyl ether. Then the ether extracts were combined and thoroughly washed with further ammonium chloride (300 mL), water (300 mL), and brine (300 mL) before drying (MgSO4) and concentrating in vacuo to give a dark brown gum, which was purified by flash column chromatography (hexane/ethyl acetate 9 : 1) to give S2 (1.16 g, 59% overall yield). The spectral data obtained were in accordance with those described in the literature[3].

Compound S3: Phosphorus oxychloride (0.59 mL, 1.06 eq.) was added dropwise to anhydrous DMF (5 mL) at 0 °C under N2. A solution of S2 (1.16 g, 5.9 mmol dissolved in 5 mL of DMF) was added dropwise at room temperature and the resulting mixture was stirred for 2 h. The reaction mixture was pour into ice and saturated NaHCO3 and extracted with ethyl acetate. The combined organic phase was washed with brine, dried over andydrous MgSO4, filtered and concentrated to give pure S3 (937 mg, 4.18 mmol, 70.8% overall yield). The spectral data obtained were in accordance with those described in the literature[4].

Compound S5: To a mixture of S4 (0.2 g, 2 mmol), K2CO3 (0.3 g, 2.4 mmol), 3 mL of H2O and 2 mL of EtOH was added iodomethane (0.124 mL, 2 mmol). The reaction mixture was stirred overnight at room temperature under N2 and then diluted with ethyl acetate. The organic solution was washed with brine, dried over anhydrous MgSO4, filtered and concentrated. The residue was purified by column chromatography on silica gel using methanol/dichloromethane (1 : 9) to give S5 (198 mg, 86% overall yield). The spectral data obtained were in accordance with those described in the literature[5].

Compound 1b: A mixture of S3 (224 mg, 1 mmol), S5 (114 mg, 1 mmol) and 3 drops of piperidine was refluxing in ethanol (10 mL) for 24 h. Then the reaction mixture was allowed to cool in a refrigerator with the addition of ether. The precipitate was filtered and washed with ether to give 1b (192 mg, 60% overall yield). 1H NMR (400 MHz, d6-DMSO): δ 12.01 (br, 1 H), 10.47 (br, 1 H), 8.22 (s, 1 H), 7.84-7.82 (d, 1 H), 7.42-7.40 (d, 1 H), 7.09-7.05 (t, 1 H), 6.81 (s, 1 H), 2.97 (s, 3 H). 13C NMR (100 MHz, d6-DMSO): δ 164.0, 155.0, 134.3, 128.6, 127.9, 124.9, 123.3, 121.5, 117.8, 109.5, 104.6, 101.9, 24.2. HRMS m/z (ESI) calcd for C13H10BrN3O2 ([M]+) 320.1414 found 320.0029.

3.2 Screening Procedures

Screening Procedure A: To a 10 mL round-bottomed flask charged with substrate 1b (32 mg, 0.1 mmol) and EtOH (2 mL) was added the appropriate catalyst (1 mol% metal relative to the substrate). The reaction mixture was degassed and then purged with hydrogen for two times. The resulting mixture was then stirred for 12 h at room temperature under a H2 balloon. The reaction was monitored by TLC. When the substrate 1b was totally consumed, the catalyst was recovered by centrifugation. The supernatant was concentrated under reduced pressure. The obtained residue was analyzed by 1H NMR to determine the selectivity (2b/2b+3b).

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Scheme S2 The chemo- and enantio- selective hydrogenation of 1b.

Compound 2b. For verification purpose, the residue was purified by chromatography on silica gel using CH2Cl2/MeOH (20 : 1) to give product 2b a yellow solid (30.0 mg, 0.093 mmol, 93%). 1H NMR (400 MHz, CDCl3): δ 8.33 (br, 1 H), 7.56-7.54 (d, 1 H), 7.39-7.37 (d, 1 H), 7.15 (d, 1 H), 7.05-7.01 (t, 1 H), 5.44 (br, 1 H), 4.30-4.27 (ddd, 1 H), 3.46-3.42 (dd, 1 H), 3.03-2.99 (t, 1 H), 2.97 (s, 3 H). 13C NMR (100 MHz, CDCl3): δ 173.4, 157.2, 135.0, 128.1, 125.0, 123.6, 121.2, 117.8, 111.2, 105.1, 57.9, 28.2, 24.6. HRMS m/z (ESI) calculated for C13H12BrN3O2 ([M]+) 322.1573, found 322.0012.

The screening results were compiled in Table 1 in the text.

3.3 Catalyst Recovery and Recycling

Following screening procedure A, to a 10 mL flask charged with substrate 1b (32.0 mg, 0.10 mmol) and EtOH (2 mL) was added the Pt1Au1/C catalyst (1 mol% metal relative to the substrate). The reaction mixture was degassed and then purged with hydrogen for two times. The resulting mixture was then stirred for 12 h at room temperature under a H2 balloon. The reaction was monitored by TLC. When the substrate 1b was totally consumed, the catalyst was recovered by filtration. The filtrate was concentrated under reduced pressure and purified by column chromatography using CH2Cl2/MeOH (20 : 1) to give product 2b as a yellow solid (29.1 mg, 0.09 mmol, 90%).

The recovered catalyst was washed with anhydrous EtOH (5 mL) three times and was reused in the next run. Following the above procedure, after the third run at a 0.1 mmol scale reaction product 2b was obtained in 91% yield (29.3 mg, 0.091 mmol).

3.4 Heterogeneous Catalysis Test

Control Reactions: To a 10 mL flask charged with substrate 1b (32.0 mg, 0.10 mmol) and EtOH (2 mL) was added the Pt1Au1/C catalyst (1 mol% metal relative to the substrate). The reaction mixture was degassed and then purged with hydrogen for two times. The resulting mixture was then stirred at room temperature under a H2 balloon. After 4 h, an aliquot (0.1 mL) of the reaction was syringed out and dissolved in 0.5 mL CDCl3. 1H NMR indicated that the ratio of 2b:1b = 43:57. At the same time, the remained reaction solution was filtered. The supernatant was transfer to a new flask and was allowed to react for another 8 h upon when 1H NMR showed that no further conversion took place (2b:1b = 45:55).

Morphology study: TEM image shows that the recycled catalyst did not have obvious changes in the shape and size (Figure S4b) compared to the fresh one (Figure S4a). The average size of particles was 9.3 nm.

Figure S4 Representative TEM images and size distribution of (a) fresh and (b) the recycled catalyst; (c) HRTEM image and (d) HAADF-STEM image of the recycled catalyst.

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Composition analysis: Leaching of Pt were found to be less than 0.05 mg/L and leaching of Au was found to be less than 0.01 mg/L, respectively (Table S1). ICP result showed that the spent catalyst was composed of 51.0 % of Pt and 49.0 % of Au atoms (Table S1), in accordance to the designed composition of the fresh catalyst. EDX analysis of the recycled catalyst verified the same observation (Figure S5).

Table S1 Metal ion content of the recycled PtAu/C and the filtrate after the reaction

Metal ion content Entry Sample

Pt Au 1 the recycled PtAu/C after the 3rd cycle 2.26 g/100 g sample 2.19 g/100 g sample 2 filtrate after the reaction < 0.05 mg/L < 0.01 mg/L

The EDX spectrum of the recycled catalyst shows that the analyzed atomic ratio (Pt/Au) was 49.70 % : 50.30 % (Figure S5), which was

consistent with that of the fresh catalyst.

Figure S5 EDX spectrum of the recycled catalyst.

Crystalline structure analysis: The crystalline structure of the fresh and the recycled catalysts was characterized by XRD. Figure S6 shows the different diffraction peaks, which can be indexed to (111), (200), (220) and (311) facets of the catalyst. There is no visible difference between XRD patterns of the fresh catalyst and the recycled catalyst.

Figure S6 XRD patterns of the fresh and the recycled catalyst.

Surface chemical analysis: XPS analysis of the fresh and recycled Pt1Au1/C was performed to collect the survey of Pt 4f and Au 4f signals (Figure S7a). As shown in Figures 7b-c, the peaks at 71.3 and 74.8 eV could be assigned to Pt 4f7/2 and Pt 4f5/2 while the peaks at 84.2 and 87.9 eV could be attributed to Au 4f7/2 and Au 4f5/2 of Pt1Au1/C with binding energy calibrated with C1s = 284.8 eV. In the Pt 4f7/2 core electrons region for the fresh and recycled catalysts, one signal was detected at 72.3 eV, which was related to the presence of Pt2+ as PtO. The results showed the as-prepared Pt1Au1/C was composed of Pt0, Pt2+ and Au0. Based on our measurement, 8.5 % and 5.8 % of the surface Pt atoms for the fresh and recycled catalysts were in the 2+ oxidation state, respectively. Additionally, the surface composition of Pt and Au elements in the fresh and the recycled catalyst were analyzed by XPS (Table S2).

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Figure S7 (a) XPS spectra of the fresh and recycled catalyst, (b) fitted Pt 4f spectra of the fresh catalyst, (c) fitted Pt 4f spectra of the recycled catalyst, (d) fitted Au 4f spectra of the fresh catalyst and (e) fitted Au 4f spectra of the recycled catalyst.

Table S2 Surface composition of the fresh and recycled catalysts analyzed by XPS

Content (%) Pt Au

Fresh catalyst 59.4 40.6 Recycled catalyst 60.0 40.0

4 Substrate Scope Study

4.1 Preparation of Substrates

(E)-hex-3-enyl 4-bromobenzoate (1g). 4-Bromobenzoic acid (406.1 mg, 2 mmol) and thionyl chloride (10 mL, 139 mmol) were combined in a 25 mL round-bottomed flask equipped with a stirbar and a water condenser, at which point the mixture was refluxed for 12 h. After cooling to room temperature, the mixture was concentrated to give 4-bromobenzoyl chloride as a white solid (390.6 mg, 89 %). 1H NMR (400 MHz, CDCl3)[6]: δ 7.95-7.93 (d, 2 H), 7.64-7.62 (d, 2 H).

In a 50 mL round-bottomed flask, 4-bromobenzoyl chloride (219.5 mg, 1.0 mmol) was dissolved in 20 mL of CH2Cl2. (E)-hex-3-en-1-ol (2 eq., 242 μL) and triethylamine (3 eq., 422 μL) were then added into the flask, respectively. The reaction mixture was stirred at room temperature for 12 h. After removal of the solvent in a vacuum, the residue was washed by NaOH solution and extracted with diethyl ester. Then the organic phase was dried over anhydrous Na2SO4, filtered and evaporated. Purification by column chromatography on silica gel using petroleum ester/ethyl acetate (9 : 1) of the crude product afforded 1g as a colorless oil (280.3 mg, 0.99 mmol, 99%). 1H NMR (400 MHz, CDCl3): δ 7.90-7.88 (d, 2 H), 7.58-7.56 (d, 2 H), 5.57-5.50 (m, 1 H), 5.42-5.35 (m, 1 H), 4.33-4.29 (t, 2 H), 2.54-2.48 (m, 2 H), 2.12-2.05 (m, 2 H), 0.99-0.95 (t, 3 H). 13C NMR (100 MHz, CDCl3): δ 165.0, 133.9, 130.8, 130.2, 128.5, 127.1, 122.7, 63.9, 26.8, 19.8, 13.4. HRMS m/z (ESI) calcd for C13H15BrO2 [M]+ 283.1610 found 283.0527.

(E)-4-(4-bromophenyl)but-3-en-2-one (1h). The compound was prepared according to the literature[7] with slight modification. A mixture of 4-bromobenzaldehyde (186.9 mg, 1.0 mmol) and 1,1,1-trifluoropentane-2,4- dione (1 eq., 123 μL) in dichloromethane (20 mL) was treated with piperidine (10 eq., 1 mL) slowly dropwise, the contents were stirred at room temperature until complete consumption of the starting material had occurred, as monitored by TLC. After the reaction was over, the solvent was evaporated in a vacuum. The residue was purified

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by column chromatography using petroleum ester/ethyl acetate (9 : 1) to afford 1h as a colorless solid (135.1 mg, 0.60 mmol, 60%). 1H NMR (CDCl3)[6]: δ 7.54-7.52 (d, 2 H), 7.46-7.39 (m, 3 H), 6.72-6.68 (d, 1 H), 2.38 (s, 3 H).

(E)-methyl 3-(4-bromophenyl)acrylate (1k). A solution of (E)-3-(4-bromophenyl)acrylic acid (458.7 mg, 2 mmol) in SOCl2 (10 mL, 138 mmol) was heated under reflux for 12 h. After cooling to room temperature, the mixture was evaporated to give (E)-3-(4-bromophenyl)acryloyl chloride as a yellow oil (441.9 mg, 1.8 mmol, 90 %). 1H NMR (400 MHz, CDCl3)[8]: δ 7.79-7.75 (d, 1 H), 7.59-7.57 (d, 2 H), 7.45-7.43 (d, 2 H), 6.66-6.62 (d, 1 H).

A solution of (E)-3-(4-bromophenyl)acryloyl chloride (245.5 mg, 1.0 mmol) in 10 mL of methanol was heated under refulx for 12 h. After cooling to room temperature, the mixture was evaporated to give 1k as a yellow oil (238.7 mg, 0.99 mmol, 99%). 1H NMR (400 MHz, CDCl3)[9]: δ 7.64-7.60 (d, 1 H), 7.53-7.51 (d, 2 H), 7.39-7.37 (d, 2 H), 6.44-6.40 (d, 1 H), 3.81 (s, 3 H).

4.2 Reaction Procedure and Characterization of Products

Bromo-2-ethylbenzene (2c). In a 25 mL round-bottomed flask, the substrate 1c (66 μL, 0.5 mmol) was dissolved in MeOH (3 mL).

Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration. Finally the filtrate obtained was tested for GC-MS. GC retention time (min.): 8.7. MS[10]: 51, 63, 77, 90, 105, 169, 184 ([M]+). Conversion > 99%, selectivity 86%.

Bromo-3-ethylbenzene (2d). In a 25 mL round-bottomed flask, the substrate 1d (66 μL, 0.5 mmol) was dissolved in MeOH (3 mL).


Bromo-4-ethylbenzene (2e). In a 25 mL round-bottomed flask, the substrate 1e (66 μL, 0.5 mmol) was dissolved in MeOH (3 mL).


1-Chloro-4-ethylbenzene (2f). In a 25 mL round-bottomed flask, the substrate 1f (61 μL, 0.5 mmol) was dissolved in MeOH (3 mL).

Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration. Finally the filtrate obtained was tested for GC-MS analysis. GC retention time (min.): 7.2. MS[10]: 51, 63, 77, 105, 125, 140 ([M]+) . Conversion > 99%, selectivity >99 %.

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Hexyl 4-bromobenzoate (2g). In a 25 mL round-bottomed flask, the substrate 1g (141.6 mg, 0.5 mmol) was dissolved in MeOH (3 mL). Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration and the filtrate obtained was evaporated. Finally, the residue was purified by column chromatography on silica gel using petroleum/ethyl acetate (10 : 1) to give 2g as a pale yellow oil (141.2 mg, 0.495 mmol, 99%). 1H NMR (400 MHz, CDCl3)[12]: δ 7.91 -7.89 (d, 2 H), 7.58-7.56 (d, 2 H), 4.32-4.29 (t, 3 H), 1.79-1.72 (m, 2 H), 1.45-1.37 (m, 2 H), 1.36-1.32 (m, 2 H), 0.92-0.88 (t, 3 H).

4-(4-Bromophenyl)butan-2-one (2h). In a 25 mL round-bottomed flask, the substrate 1h (112.5 mg, 0.5 mmol) was dissolved in MeOH

(3 mL). Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration and the filtrate obtained was evaporated. Finally, the residue was purified by column chromatography on silica gel (petroleum ester/ethyl acetate 9 : 1) to give 2h as a pale yellow oil (92.1 mg, 0.405 mmol, 81%). 1H NMR (400 MHz, CDCl3)[13]: δ 7.40 -7.38 (d, 2 H), 7.07-7.05 (d, 2 H), 2.86-2.83 (t, 2 H), 2.75-2.72 (t, 2 H), 2.13 (s, 3 H).

4-(2,4-Dichlorophenyl)butan-2-one (2i). In a 25 mL round-bottomed flask, the substrate 1i (107.5 mg, 0.5 mmol) was dissolved in THF

(3 mL). Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration and the filtrate obtained was evaporated. Finally, the residue was purified by column chromatography on silica gel using petroleum ester/ethyl acetate (9 : 1) to give 2i as an amber solid (82.5 mg, 0.38 mmol, 76%). 1H NMR (400 MHz, CDCl3)[13]: δ 7.34-7.33 (d, 1 H), 7.18-7.16 (d, 1 H), 7.15-7.13 (dd, 1 H), 2.97-2.93 (t, 2 H), 2.76-2.72 (t, 2 H), 2.14 (s, 3 H).

3-(4-Chlorophenyl)propanoic acid (2j). In a 25 mL round-bottomed flask, the substrate 1j (91.3 mg, 0.5 mmol) was dissolved in THF

(3 mL). Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration and the filtrate obtained was evaporated. Finally, the residue was purified by column chromatography on silica gel using petroleum ester/ethyl acetate (4 : 1) to give 2j as a white solid (84.9 mg, 0.46 mmol, 92%). 1H NMR (400 MHz, CDCl3)[14]: δ 10.57 (br, 1 H), 7.27-7.25 (d, 2 H), 7.15-7.12 (d, 2 H), 2.94-2.90 (t, 2 H), 2.68-2.64 (t, 2 H).

Methyl 3-(4-bromophenyl)propanoate (2k). In a 25 mL round-bottomed flask, the substrate 1k (120.5 mg, 0.5 mmol) was dissolved in

MeOH (3 mL). Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration and the filtrate obtained was evaporated. Finally, the residue was purified by column chromatography on silica gel using petroleum ester/ethyl acetate (9 : 1) to give 2k as a colorless oil (119.1 mg, 0.49 mmol, 98%). 1H NMR (400 MHz, CDCl3)[15]: δ 7.41-7.39 (d, 2 H), 7.08-7.06 (d, 2 H), 3.66 (s, 3 H), 2.92-2.88 (t, 2 H), 2.63-2.59 (t, 2 H).

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Methyl 3-(4-chlorophenyl)propanoate (2l). In a 25 mL round-bottomed flask, the substrate 1l (98.3 mg, 0.5 mmol) was dissolved in MeOH (3 mL). Subsequently, Pt1Au1/C (20 mg, 1 mol% metal relative to the substrate) was added into the flask. The reaction mixture was degassed two times, replacing each time the vacuum by hydrogen, then stirred for 12 h at room temperature under an H2 balloon. When the reaction was over, the catalyst was recovered by filtration and the filtrate obtained was evaporated. Finally, the residue was purified by column chromatography on silica gel using petroleum ester/ethyl acetate (9 : 1) to give 2l as a colorless oil (97.3 mg, 0.49 mmol, 98%). 1H NMR (400 MHz, CDCl3)[16]: δ 7.22-7.20 (d, 2 H), 7.11-7.08 (d, 2 H), 3.62 (s, 3 H), 2.90-2.86 (t, 3 H), 2.59-2.55 (t, 3 H).

5 Asymmetric Hydrogenation of 1b

5.1 Reaction Procedure

To a 10 mL flask charged with the proper catalyst (1 mol% or 2 mol% metal relative to the substrate) and cinchonidine (0.5 eq. or 1.0 eq. or 1.5 eq. or 2.0 eq.) was added EtOH (2 mL). This mixture was stirred for 30 min at room temperature. To this mixture was added substrate 1b (32.0 mg, 0.10 mmol). After the resulting mixture was degassed and purged with hydrogen (2 times) and stirred at room temperature under a H2 balloon. When the substrate 1b was totally consumed, the catalyst was removed by filtration. The filtrate was rapidly purified by column chromatography using CH2Cl2/MeOH (20 : 1) to give product 2b as a yellow solid.

5.2 Analytic Chiral HPLC Data

A fraction of the obtained solid (2 mg) was dissolved in 1 mL methanol and was analyzed by chiral HPLC. The enantiomeric ratio was determined by SHZMADZU LC-20AT HPLC using CHIRALPAK ID column (Hexanes/EtOH : 84/16, 1 mL/min, 254 nm, tR of (minor) = 10.6 min, tR of (major) = 12.9 min.

Table S3 Cinchonidine modified catalyst for asymmetric hydrogenation of 1b

Catalyst (mol%) cinchonidine (mol%) Reaction time (h) 2b: 3b Yield % (Conversion) EE % HPLC 1 Pt1Au1/C (1.0) 0.5 12 >95:5 92 (>99%) 21.2 Fig. S8 2 Pt1Au1/C (1.0) 1.0 24 >95:5 67 (80%) 34.8 Fig. S9 3 Pt1Au1/C (1.0) 1.5 24 >95:5 34 (41%) 44.1 Fig. S10 4 Pt1Au1/C (1.0) 2.0 24 -- 0 (<5%) -- 5 Pt1Au1/C (2.0) 2.0 24 >95:5 93 (>99%) 37.8 Fig. S11 6 Pt1Au1/C (2.0) 3.0 24 >95:5 90 (>99%) 50.4 Fig. S12 7 Pt1Au1/C (2.0) 4.0 24 -- 0 (< 5%) -- 8 Pt/C (2.0) 3.0 12 22:78 17%(>99%) -- 9 Pt NCs/C (2.0) 3.0 12 67:33 60%(>99%) --

10 Pt NCs/C (2.0) 4.0 24 75:25 -- (17%)

Figure S8 HPLC data of reaction 1 in Table S3.

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6 References [1] Cuny, G. D.; Yuan, J.; Jagtap, P.; Degterev, A. U. S. Pat. 0119260, 2005. [2] Wu, J.; Zhang, J.; Peng, Z.; Yang, S.; Wagner, F. T.; Yang, H. J. Am. Chem. Soc. 2010, 132, 4984. [3] Yaeko, K.-Y.; Chiharu, O.; Kiminari, Y.; Yasuyuki, U.; Shiho, A.; Noriko, S.; Toshitsugu, K.; Hiroaki, T.; Yoshihiro, H. Tetrahedron, 2002, 58, 7851. [4] Berthelot, A.; Piguel, S.; Le Dour, G.; Vidal, J. J. Org. Chem. 2003, 68, 9835. [5] Janin, Y. L.; Huel, C.; Flad, G.; Thirot, S. Eur. J. Org. Chem. 2002, 67, 1763.

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[6] Azam, M. S.; Fenwick, S. L.; Gibbs-Davis, J. M. Langmuir 2011, 27, 741. [7] Raju, B. C.; Suman, P. Chem. Eur. J. 2010, 16, 11840. [8] Mikroyannidis, J. A.; Spiliopoulos, I. K.; Kasimis, T. S.; Kulkarni, A. P.; Jenekhe, S. A. Macromolecules 2003, 36, 9295. [9] Ruan, J.; Li, X.; Saidi, O.; Xiao, J. J. Am. Chem. Soc. 2008, 130, 2424. [10] McLafferty, F. W. Anal. Chem. 1962, 34, 16. [11] Brown, P. Org. Mass Spectrom. 1969, 2, 1317. [12] Herder, M.; Pätzel, M.; Grubert, L.; Hecht, S. Chem. Commun. 2011, 47, 460. [13] Cao, J.-J.; Zhou, F.; Zhou, J. Angew. Chem. 2010, 122, 5096-5100; Angew. Chem. Int. Ed. 2010, 49, 4976. [14] Pearson, A. J.; Lee, K. J. Org. Chem. 1994, 59, 2257. [15] Zaidlewicz, M.; Wolan, A. J. Organmet. Chem. 2002, 657, 129. [16] Louie, J.; Bielawski, C. W.; Grubbs, R. H. J. Am. Chem. Soc. 2001, 123, 11312.

7 Appendix: 1H and 13C NMR Spectra of Compounds

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