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Ortega DD, Pavlakovich N, Shon YS. Effects of lipid bilayer encapsulation and lipid composition on the catalytic activity and colloidal stability of hydrophobic palladium nanoparticles in water. RSC Adv 2022; 12:21866-21874. [PMID: 36043067 PMCID: PMC9361304 DOI: 10.1039/d2ra03974e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/25/2022] [Indexed: 11/21/2022] Open
Abstract
This article shows the preparation of a lipid-nanoparticle assembly (LNA) which contains hydrophobic palladium nanoparticles (PdNPs) within the hydrophobic regions of the liposomal micelles. To understand the colloidal stability and catalytic activity of LNAs, the structure–property relationships of LNAs are investigated by manipulating the lipid composition and reaction temperature. The studies of LNAs using dynamic light scattering (DLS), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) show decreased colloidal stability with the incorporation of PdNPs compared to their counterpart 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) liposomes without PdNPs. LNAs with PdNPs catalyze the hydrogenation of 1-octene and its isomers to octane under one atm hydrogen gas and at room temperature within 24 h. The kinetic studies show that the isomerization of 1-octene to 2-octene occurs more favorably in the early stage of the reactions, which is followed by the subsequent hydrogenation of all octene isomers. The studies on temperature effects indicate that there is a significant increase in conversion yield of substrates when the reaction temperature increases from 22 to 37 °C, which correspond to room temperature and biological temperature, respectively. Phase transition of DSPC-PdNP LNAs from gel to liquid crystalline phase changing the fluidity of the bilayer is proposed to be the main reason for dramatic increases in the catalytic activity of the LNAs. It is also found that the rate of hydrogenation is dependent on the lipid composition of LNAs with the presence of cholesterol having a negative influence on the catalytic activity of LNAs while increasing their colloidal stability. Hydrophobic micellization effect and dynamic lipid bilayer–substrate interactions enhance the catalytic activity of hydrophobic Pd nanoparticles embedded in liposomal assemblies.![]()
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Affiliation(s)
- Dominick D Ortega
- Department of Chemistry and Biochemistry, California State University, Long Beach 1250 Bellflower Blvd. Long Beach CA 90840 Unites States
| | - Nicholas Pavlakovich
- Department of Chemistry and Biochemistry, California State University, Long Beach 1250 Bellflower Blvd. Long Beach CA 90840 Unites States
| | - Young-Seok Shon
- Department of Chemistry and Biochemistry, California State University, Long Beach 1250 Bellflower Blvd. Long Beach CA 90840 Unites States
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2
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Reina A, Dang-Bao T, Guerrero-Ríos I, Gómez M. Palladium and Copper: Advantageous Nanocatalysts for Multi-Step Transformations. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:1891. [PMID: 34443727 PMCID: PMC8401531 DOI: 10.3390/nano11081891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/16/2021] [Accepted: 07/19/2021] [Indexed: 12/13/2022]
Abstract
Metal nanoparticles have been deeply studied in the last few decades due to their attractive physical and chemical properties, finding a wide range of applications in several fields. Among them, well-defined nano-structures can combine the main advantages of heterogeneous and homogeneous catalysts. Especially, catalyzed multi-step processes for the production of added-value chemicals represent straightforward synthetic methodologies, including tandem and sequential reactions that avoid the purification of intermediate compounds. In particular, palladium- and copper-based nanocatalysts are often applied, becoming a current strategy in the sustainable synthesis of fine chemicals. The rational tailoring of nanosized materials involving both those immobilized on solid supports and liquid phases and their applications in organic synthesis are herein reviewed.
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Affiliation(s)
- Antonio Reina
- Departamento de Química Inorgánica y Nuclear, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
| | - Trung Dang-Bao
- Faculty of Chemical Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City 700000, Vietnam
- Vietnam National University—Ho Chi Minh City (VNU—HCM), Ho Chi Minh City 700000, Vietnam
| | - Itzel Guerrero-Ríos
- Departamento de Química Inorgánica y Nuclear, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
| | - Montserrat Gómez
- Laboratoire Hétérochimie Fondamentale et Appliquée, Université Toulouse 3—Paul Sabatier, UMR CNRS 5069, 118 Route de Narbonne, CEDEX 9, 31062 Toulouse, France;
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3
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Alam AM, Shon YS. Water-Soluble Noble Metal Nanoparticle Catalysts Capped with Small Organic Molecules for Organic Transformations in Water. ACS APPLIED NANO MATERIALS 2021; 4:3294-3318. [PMID: 34095774 PMCID: PMC8171274 DOI: 10.1021/acsanm.1c00335] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This article recaps a variety of interesting catalytic studies based on solubilized and freely movable noble metal nanoparticle catalysts employed for organic reactions in either pure water or water-organic biphasic systems. Small organic ligand-capped metal nanoparticles are fundamentally attractive materials due to their enormous potential as a well-defined system that can provide spatial control near active catalytic sites. The nanoparticle catalysts are first grouped based on the synthetic method (direct reduction, phase transfer, and redispersion) and then again based on the type of reaction such as alkene hydrogenation, arene hydrogenation, nitroaromatic reduction, carbon-carbon coupling reactions, etc. The impacts of various ligands on the catalytic activity and selectivity of semi-heterogeneous nanoparticles in water are discussed in detail. The catalytic systems using polymers, dendrimers, and ionic liquids as supporting or protecting materials are excluded from the subject of this review.
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Affiliation(s)
- Al-Mahmnur Alam
- Department of Chemistry and Biochemistry and the Keck Energy and Materials Program (KEMP), California State University, Long Beach, Long Beach, California 90840, United States
| | - Young-Seok Shon
- Department of Chemistry and Biochemistry and the Keck Energy and Materials Program (KEMP), California State University, Long Beach, Long Beach, California 90840, United States
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4
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Kuwahara Y, Kango H, Yamashita H. Pd Nanoparticles and Aminopolymers Confined in Hollow Silica Spheres as Efficient and Reusable Heterogeneous Catalysts for Semihydrogenation of Alkynes. ACS Catal 2019. [DOI: 10.1021/acscatal.8b04653] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yasutaka Kuwahara
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
| | - Hiroto Kango
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Hiromi Yamashita
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
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5
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San KA, Shon YS. Synthesis of Alkanethiolate-Capped Metal Nanoparticles Using Alkyl Thiosulfate Ligand Precursors: A Method to Generate Promising Reagents for Selective Catalysis. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E346. [PMID: 29783714 PMCID: PMC5977360 DOI: 10.3390/nano8050346] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 12/27/2022]
Abstract
Evaluation of metal nanoparticle catalysts functionalized with well-defined thiolate ligands can be potentially important because such systems can provide a spatial control in the reactivity and selectivity of catalysts. A synthetic method utilizing Bunte salts (sodium S-alkylthiosulfates) allows the formation of metal nanoparticles (Au, Ag, Pd, Pt, and Ir) capped with alkanethiolate ligands. The catalysis studies on Pd nanoparticles show a strong correlation between the surface ligand structure/composition and the catalytic activity and selectivity for the hydrogenation/isomerization of alkenes, dienes, trienes, and allylic alcohols. The high selectivity of Pd nanoparticles is driven by the controlled electronic properties of the Pd surface limiting the formation of Pd⁻alkene adducts (or intermediates) necessary for (additional) hydrogenation. The synthesis of water soluble Pd nanoparticles using ω-carboxylate-S-alkanethiosulfate salts is successfully achieved and these Pd nanoparticles are examined for the hydrogenation of various unsaturated compounds in both homogeneous and heterogeneous environments. Alkanethiolate-capped Pt nanoparticles are also successfully synthesized and further investigated for the hydrogenation of various alkynes to understand their geometric and electronic surface properties. The high catalytic activity of activated terminal alkynes, but the significantly low activity of internal alkynes and unactivated terminal alkynes, are observed for Pt nanoparticles.
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Affiliation(s)
- Khin Aye San
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840, USA.
| | - Young-Seok Shon
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840, USA.
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Maung MS, Shon YS. Effects of Noncovalent Interactions on the Catalytic Activity of Unsupported Colloidal Palladium Nanoparticles Stabilized with Thiolate Ligands. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:20882-20891. [PMID: 29326755 PMCID: PMC5758047 DOI: 10.1021/acs.jpcc.7b07109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This article presents the systematic evaluation of colloidal palladium nanoparticles functionalized with well-defined small organic ligands that provide spatial control of the geometric and electronic surface properties of nanoparticle catalysts. Palladium nanoparticles stabilized with thiolate ligands of different structures and functionalities (linear alkyl vs cyclohexyl vs phenyl) are synthesized using the thiosulfate protocol in a two-phase system. The structure and composition of palladium nanoparticles are characterized using transmission electron microscopy, thermogravimetric analysis, NMR, and UV-vis spectroscopies. The catalysis studies show that the chemical and structural compositions of monolayers surrounding the nanoparticle core greatly influence the overall activity and selectivity of colloidal palladium nanoparticle catalysts for the hydrogenation, isomerization, and hydrogenolysis of allylic alcohols. Especially, noncovalent interactions between surface phenyl ligands and incoming aromatic substrates are found to have a profound influence on the selectivity of colloidal palladium nanoparticles.
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Affiliation(s)
| | - Young-Seok Shon
- Corresponding Author: . Telephone: 562-985-4466. Fax: 562-985-8547
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7
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Chen TA, Shon YS. Alkanethiolate-capped palladium nanoparticles for selective catalytic hydrogenation of dienes and trienes. Catal Sci Technol 2017; 7:4823-4829. [PMID: 29713450 DOI: 10.1039/c7cy01880k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Selective hydrogenation of dienes and trienes is an important process in the pharmaceutical and chemical industries. Our group previously reported that the thiosulfate protocol using a sodium S-alkylthiosulfate ligand could generate catalytically active Pd nanoparticles (PdNP) capped with a lower density of alkanethio-late ligands. This homogeneously soluble PdNP catalyst offers several advantages such as little contamination via Pd leaching and easy separation and recycling. In addition, the high activity of PdNP allows the reactions to be completed under mild conditions, at room temperature and atmospheric pressure. Herein, a PdNP catalyst capped with octanethiolate ligands (C8 PdNP) is investigated for the selective hydrogenation of conjugated dienes into monoenes. The strong influence of the thiolate ligands on the chemical and electronic properties of the Pd surface is confirmed by mechanistic studies and highly selective catalysis results. The studies also suggest two major routes for the conjugated diene hydrogenation: the 1,2-addition and 1,4-addition of hydrogen. The selectivity between two mono-hydrogenation products is controlled by the steric interaction of substrates and the thermodynamic stability of products. The catalytic hydrogenation of trienes also results in the almost quantitative formation of mono-hydrogenation products, the isolated dienes, from both ocimene and myrcene.
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Affiliation(s)
- Ting-An Chen
- Department of Chemistry and Biochemistry and Keck Energy Materials Program, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California 90840, USA
| | - Young-Seok Shon
- Department of Chemistry and Biochemistry and Keck Energy Materials Program, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California 90840, USA
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8
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Chuc LT, Chen CS, Lo WS, Shen PC, Hsuan YC, Tsai HHG, Shieh FK, Hou DR. Long-Range Olefin Isomerization Catalyzed by Palladium(0) Nanoparticles. ACS OMEGA 2017; 2:698-711. [PMID: 31457465 PMCID: PMC6640945 DOI: 10.1021/acsomega.6b00509] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 02/14/2017] [Indexed: 06/10/2023]
Abstract
Long-range olefin isomerization of 2-alkenylbenzoic acid derivatives going through two to five sp3-carbon atoms to give (E)-alkenes was achieved with palladium(0) nanoparticles. The substrate scope of this reaction includes carboxylic acid, ester, and primary to tertiary amides and tolerates various substituents on the benzene ring. This isomerization reaction was catalyzed by recyclable Pd(0) nanoparticles, prepared in situ from PdCl2 and characterized by X-ray powder diffraction and scanning electron microscopy analyses. 1H NMR studies and kinetic modeling supported a stepwise process. This new process was applied to synthesize a natural dihydroisocoumarin with good efficiency.
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Chen V, Pan H, Jacobs R, Derakhshan S, Shon YS. Influence of Graphene Oxide Supports on Solution-Phase Catalysis of Thiolate-Protected Palladium Nanoparticles in Water. NEW J CHEM 2016; 41:177-183. [PMID: 28652688 DOI: 10.1039/c6nj02898e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The influence of graphene oxide supports and thiolate surface ligands on the catalytic activity of colloidal Pd nanoparticles for alkyne hydrogenation in water is investigated. The studies show that unsupported, water-soluble thiolate-capped Pd nanoparticle catalysts favor the semi-hydrogenation over full-hydrogenation of dimethyl acetylene dicarboxylate (DMAD) under the atmospheric pressure and at room temperature. Pd nanoparticles supported on graphene oxide exhibit a similar activity for the hydrogenation of DMAD, but they show an improved long-term colloidal stability in aqueous solution after multiple catalytic cycles. After the heat treatment of Pd nanoparticles supported on graphene oxide at 300 °C, these heated hybrids exhibit an enhanced catalytic activity towards the full-hydrogenation. Overall, the studies suggest some influences of graphene oxide supports on the stability and thiolate surface ligands on the activity and selectivity of Pd nanoparticle catalysts.
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Affiliation(s)
- Vivian Chen
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California, 90840-9507 (USA)
| | - Hanqing Pan
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California, 90840-9507 (USA)
| | - Roxanne Jacobs
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California, 90840-9507 (USA)
| | - Shahab Derakhshan
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California, 90840-9507 (USA)
| | - Young-Seok Shon
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California, 90840-9507 (USA)
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10
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Zsolnai D, Mayer P, Szőri K, London G. Pd/Al2O3-catalysed redox isomerisation of allyl alcohol: application in aldol condensation and oxidative heterocyclization reactions. Catal Sci Technol 2016. [DOI: 10.1039/c5cy01722j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The application of the Pd/Al2O3 catalyst in allyl alcohol isomerization and subsequent aldol-condensation and heterocyclization reactions is described.
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Affiliation(s)
- Dániel Zsolnai
- Department of Organic Chemistry
- University of Szeged
- H-6720 Szeged
- Hungary
| | - Péter Mayer
- Department of Organic Chemistry
- University of Szeged
- H-6720 Szeged
- Hungary
| | - Kornél Szőri
- MTA-SZTE Stereochemistry Research Group
- H-6720 Szeged
- Hungary
| | - Gábor London
- MTA-SZTE Stereochemistry Research Group
- H-6720 Szeged
- Hungary
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11
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Rogers SM, Dimitratos N, Jones W, Bowker M, Kanaras AG, Wells PP, Catlow CRA, Parker SF. The adsorbed state of a thiol on palladium nanoparticles. Phys Chem Chem Phys 2016; 18:17265-71. [DOI: 10.1039/c6cp00957c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Imaging, spectroscopy and computation show that 1-dodecanethiol forms largely ordered 1-dodecanethiolate on the surface of palladium nanoparticles.
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Affiliation(s)
- Scott M. Rogers
- Department of Chemistry
- University College London
- London
- UK
- UK Catalysis Hub
| | - Nikolaos Dimitratos
- Department of Chemistry
- University College London
- London
- UK
- Cardiff Catalysis Institute
| | - Wilm Jones
- UK Catalysis Hub
- Research Complex at Harwell
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | - Michael Bowker
- UK Catalysis Hub
- Research Complex at Harwell
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | - Antonios G. Kanaras
- School of Physics and Astronomy
- Faculty of Physical Sciences and Engineering
- University of Southampton
- Highfield
- Southampton
| | - Peter P. Wells
- Department of Chemistry
- University College London
- London
- UK
- UK Catalysis Hub
| | | | - Stewart F. Parker
- UK Catalysis Hub
- Research Complex at Harwell
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
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12
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Gavia DJ, Shon YS. Catalytic Properties of Unsupported Palladium Nanoparticle Surfaces Capped with Small Organic Ligands. ChemCatChem 2015; 7:892-900. [PMID: 25937846 PMCID: PMC4415887 DOI: 10.1002/cctc.201402865] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Indexed: 11/11/2022]
Abstract
This Minireview summarizes a variety of intriguing catalytic studies accomplished by employing unsupported, either solubilized or freely mobilized, and small organic ligand-capped palladium nanoparticles as catalysts. Small organic ligands are gaining more attention as nanoparticle stabilizers and alternates to larger organic supports, such as polymers and dendrimers, owing to their tremendous potential for a well-defined system with spatial control in surrounding environments of reactive surfaces. The nanoparticle catalysts are grouped depending on the type of surface stabilizers with reactive head groups, which include thiolate, phosphine, amine, and alkyl azide. Applications for the reactions such as hydrogenation, alkene isomerization, oxidation, and carbon-carbon cross coupling reactions are extensively discussed. The systems defined as "ligandless" Pd nanoparticle catalysts and solvent (e.g. ionic liquid)-stabilized Pd nanoparticle catalysts are not discussed in this review.
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Affiliation(s)
- Diego J. Gavia
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California, 90840-9507 (USA)
| | - Young-Seok Shon
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Blvd., Long Beach, California, 90840-9507 (USA)
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Gavia DJ, Maung MS, Shon YS. Water-soluble Pd nanoparticles synthesized from ω-carboxyl-S-alkanethiosulfate ligand precursors as unimolecular micelle catalysts. ACS APPLIED MATERIALS & INTERFACES 2013; 5:12432-40. [PMID: 24246150 PMCID: PMC4072038 DOI: 10.1021/am4035043] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This report describes a two-phase synthesis of water-soluble carboxylate-functionalized alkanethiolate-capped Pd nanoparticles from ω-carboxyl-S-alkanethiosulfate sodium salts. The two-phase methodology using the thiosulfate ligand passivation protocol allowed a highly specific control over the surface ligand coverage of these nanoparticles, which are lost in a one-phase aqueous system because of the base-catalyzed hydrolysis of thiosulfate to thiolate. Systematic synthetic variations investigated in this study included the concentration of ω-carboxyl-S-alkanethiosulfate ligand precursors and reducing agent, NaBH4, and the overall ligand chain length. The resulting water-soluble Pd nanoparticles were isolated and characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), (1)H NMR, UV-vis, and FT-IR spectroscopy. Among different variations, a decrease in the molar equivalent of NaBH4 resulted in a reduction in the surface ligand density while maintaining a similar particle core size. Additionally, reducing the chain length of the thiosulfate ligand precursor also led to the formation of stable nanoparticles with a lower surface coverage. Since the metal core size of these Pd nanoparticle variations remained quite consistent, direct correlation studies between ligand properties and catalytic activities against hydrogenation/isomerization of allyl alcohol could be performed. Briefly, Pd nanoparticles dissolved in water favored the hydrogenation of allyl alcohol to 1-propanol whereas Pd nanoparticles heterogeneously dispersed in chloroform exhibited a rather high selectivity towards the isomerization product (propanal). The results suggested that the surrounding ligand environments, such as the ligand structure, conformation, and surface coverage, were crucial in determining the overall activity and selectivity of the Pd nanoparticle catalysts.
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Affiliation(s)
| | | | - Young-Seok Shon
- Corresponding Author: . Tel: 562-985-4466. Fax: 562-985-8547
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