1
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Guajardo-Maturana R, MacLeod Carey D, Rodríguez-Kessler PL, Muñoz-Castro A. On the variation of cluster core characteristics by an endohedral atom. Shape variation in 8-ce [EAu 4(PPh 3) 4] 2+ (E = N, P, As, Sb) clusters. Phys Chem Chem Phys 2024. [PMID: 39041809 DOI: 10.1039/d4cp01465k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Atomically precise gold superatoms have attracted interest owing to their suitable use as building blocks for cluster-assembled materials, favoring ordered structures with advanced properties. In this sense, expanding their versatility is a relevant issue for controlling their properties and retaining a specific nuclearity. Interestingly, the reported structure for isoelectronic [Au4N(PPh3)4]+ and [Au4Sb(PPh3)4]+ clusters denotes two contrasting shapes featuring a tetrahedral and square pyramidal structure, respectively. Herein, we further explore the [Au4E(PPh3)4]+ (E = N, P, As, Sb) series in order to evaluate energetic and structural factors determining the overall shape. Our results show a favorable [Au4(PPh3)4]4+/E3- interaction energy, predicting particular patterns in their UV-vis spectrum. Thus, the use of dopant atoms is enabled to vary the core shape and, in turn, to modify the cluster properties, which serve as a structural control, in addition to ligand-based and size approaches.
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Affiliation(s)
- Raul Guajardo-Maturana
- Instituto de Investigación Interdisciplinar en Ciencias Biomédicas SEK (I3CBSEK) Chile, Universidad SEK, Santiago, Chile
| | - Desmond MacLeod Carey
- Laboratorio de Química Inorgánica y Materiales Moleculares, Facultad de Ingenieria, Universidad Autónoma de Chile, Llano Subercaceaux 2801, San Miguel, Santiago, Chile
| | - Peter L Rodríguez-Kessler
- Centro de Investigaciones en Óptica A.C., Loma del Bosque 115, Col. Lomas del Campestre, León, Guanajuato, 37150, Mexico
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
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2
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Sikorska C, Vincent E, Schnepf A, Gaston N. Tuning the electronic structure of gold cluster-assembled materials by altering organophosphine ligands. Phys Chem Chem Phys 2024; 26:10673-10687. [PMID: 38511629 DOI: 10.1039/d3cp04027e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Superatomic clusters can be assembled to build bulk matter, where the individual characteristics are preserved. The main benefit of these materials over conventional bulk species is the capability to tailor their features by altering the physicochemical identities of individual clusters. Electronic properties of metal clusters can be modified by a protective shell of ligands that attach to the surface and make the whole nanoparticle soluble in organic or aqueous solvents. In the present work, we demonstrate that properly chosen ligands provide not only steric protection from aggregation but also tune the redox activity of metal clusters. We investigate the role of the ligands in electronic structure tunability and ligand-field splitting. Our first-principles calculations agree with the experiments, showing that phosphine-protected gold materials are small gap semiconductors. The obtained bandgaps strongly depend on the ligand used. Hence, using phosphine and organophosphine ligands should be feasible and promising while designing the novel superatom-based materials since the desired range of the bandgap might be achieved (by the proper choice of the ligand).
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Affiliation(s)
- Celina Sikorska
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand.
- Faculty of Chemistry, University of Gdanśk, Fahrenheit Union of Universities in Gdanśk, 80-308 Gdanśk, Poland
| | - Emma Vincent
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand.
| | - Andreas Schnepf
- Institut für Anorganische Chemie Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Nicola Gaston
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand.
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3
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Gaebler HM, Castiglione JR, Hamilton IP. Engineering magic number Au 19 and Au 20 cage structures using electron withdrawing atoms. Phys Chem Chem Phys 2023; 25:12107-12112. [PMID: 37083006 DOI: 10.1039/d3cp00651d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
Gold cages are a subset of gold nanoparticles and these structures are of major interest due to their favourable physiochemical properties. In order for these structures to be useful in applications, they must be chemically stable. The objective of this research is to transform non-magic number cage structures into magic number cage structures by the addition of electron-withdrawing groups on the cages. The electronic properties for Au19X and Au20X2 (X = F, Cl, Br, I) are calculated and observed. It is expected that the electron-withdrawing groups will remove the electron density from the gold cages and leave them positively charged. We first optimize the geometries of the initial gold cages and verify the structures are a local minima. From there, we attach our halogens to the gold cages and optimize the structures to determine the NICS values and HOMO-LUMO gaps. NICS values were found to be more negative when a more electronegative halogen was used. Calculations have found that Au19F and Au20F2 have the most negative NICS values, indicating greater spherical aromaticity. Iodine, being the least electronegative atom, had the most positive NICS value and smallest HOMO-LUMO gap. All calculations are compared to the magic cluster Au18 which satisfies Hirsh's 2(N + 1)2 rule for n = 2.
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Affiliation(s)
- Heather M Gaebler
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, Canada N2L 3C5.
| | - Julianna R Castiglione
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, Canada N2L 3C5.
| | - Ian P Hamilton
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, Canada N2L 3C5.
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4
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Adnan RH, Madridejos JML, Alotabi AS, Metha GF, Andersson GG. A Review of State of the Art in Phosphine Ligated Gold Clusters and Application in Catalysis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105692. [PMID: 35332703 PMCID: PMC9130904 DOI: 10.1002/advs.202105692] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/23/2022] [Indexed: 05/28/2023]
Abstract
Atomically precise gold clusters are highly desirable due to their well-defined structure which allows the study of structure-property relationships. In addition, they have potential in technological applications such as nanoscale catalysis. The structural, chemical, electronic, and optical properties of ligated gold clusters are strongly defined by the metal-ligand interaction and type of ligands. This critical feature renders gold-phosphine clusters unique and distinct from other ligand-protected gold clusters. The use of multidentate phosphines enables preparation of varying core sizes and exotic structures beyond regular polyhedrons. Weak gold-phosphorous (Au-P) bonding is advantageous for ligand exchange and removal for specific applications, such as catalysis, without agglomeration. The aim of this review is to provide a unified view of gold-phosphine clusters and to present an in-depth discussion on recent advances and key developments for these clusters. This review features the unique chemistry, structural, electronic, and optical properties of gold-phosphine clusters. Advanced characterization techniques, including synchrotron-based spectroscopy, have unraveled substantial effects of Au-P interaction on the composition-, structure-, and size-dependent properties. State-of-the-art theoretical calculations that reveal insights into experimental findings are also discussed. Finally, a discussion of the application of gold-phosphine clusters in catalysis is presented.
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Affiliation(s)
- Rohul H. Adnan
- Department of Chemistry, Faculty of ScienceCenter for Hydrogen EnergyUniversiti Teknologi Malaysia (UTM)Johor Bahru81310Malaysia
| | | | - Abdulrahman S. Alotabi
- Flinders Institute for NanoScale Science and TechnologyFlinders UniversityAdelaideSouth Australia5042Australia
- Department of PhysicsFaculty of Science and Arts in BaljurashiAlbaha UniversityBaljurashi65655Saudi Arabia
| | - Gregory F. Metha
- Department of ChemistryUniversity of AdelaideAdelaideSouth Australia5005Australia
| | - Gunther G. Andersson
- Flinders Institute for NanoScale Science and TechnologyFlinders UniversityAdelaideSouth Australia5042Australia
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5
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Brindle J, Sufyan SA, Nigra MM. Support, composition, and ligand effects in partial oxidation of benzyl alcohol using gold–copper clusters. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00137c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The effect of metallic composition, support, and ligands on catalytic performance using AuCu clusters in benzyl alcohol oxidation is investigated.
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Affiliation(s)
- Joseph Brindle
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112, USA
| | - Sayed Abu Sufyan
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112, USA
| | - Michael M. Nigra
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112, USA
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6
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Day PN, Pachter R, Nguyen KA. Calculated linear and nonlinear optical absorption spectra of phosphine-ligated gold clusters. Phys Chem Chem Phys 2022; 24:11234-11248. [DOI: 10.1039/d2cp01232d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although prediction of optical excitations of ligated gold clusters by time-dependent density functional theory (TDDFT) is relatively well-established, limitations still exist, for example in the choice of the exchange-correlation functional....
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7
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Fiedler H, Schacht J, Hammerschmidt L, Golovko V, Gaston N, Halpert JE. Emergent electronic properties in Co-deposited superatomic clusters. J Chem Phys 2021; 155:124309. [PMID: 34598587 DOI: 10.1063/5.0060302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report an intercluster compound based on co-deposition of the Au cluster [Au9(PPh3)8](NO3)3 and the fulleride KC60(THF). Electronic properties characteristic for a charge interaction between superatoms emerge within the solid state material [Au9(PPh3)8](NO3)3-x(C60)x, as confirmed by UV-VIS and Raman spectroscopy and I-V measurements. These emergent properties are related to the superatomic electronic states of the initial clusters. The material is characterized by Fourier-transform infrared spectroscopy, x-ray diffraction, Raman spectroscopy, and electrical measurements. Structural optimization and ab initio band structure calculations are performed with density functional theory to interpret the nature of the electronic states in the material; Bader charge calculations assign effective oxidation states in support of the superatomic model of cluster interactions.
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Affiliation(s)
- Holger Fiedler
- The MacDiarmid Institute of Advanced Materials and Nanotechnology, A New Zealand Centre of Research Excellence, Wellington New Zealand
| | - Julia Schacht
- The MacDiarmid Institute of Advanced Materials and Nanotechnology, A New Zealand Centre of Research Excellence, Wellington New Zealand
| | - Lukas Hammerschmidt
- The MacDiarmid Institute of Advanced Materials and Nanotechnology, A New Zealand Centre of Research Excellence, Wellington New Zealand
| | - Vladimir Golovko
- The MacDiarmid Institute of Advanced Materials and Nanotechnology, A New Zealand Centre of Research Excellence, Wellington New Zealand
| | - Nicola Gaston
- The MacDiarmid Institute of Advanced Materials and Nanotechnology, A New Zealand Centre of Research Excellence, Wellington New Zealand
| | - Jonathan E Halpert
- The MacDiarmid Institute of Advanced Materials and Nanotechnology, A New Zealand Centre of Research Excellence, Wellington New Zealand
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8
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Li Q, Huang B, Yang S, Zhang H, Chai J, Pei Y, Zhu M. Unraveling the Nucleation Process from a Au(I)-SR Complex to Transition-Size Nanoclusters. J Am Chem Soc 2021; 143:15224-15232. [PMID: 34498861 DOI: 10.1021/jacs.1c06354] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Atomically precise noble metal nanoclusters provide a critical benchmark for the fundamental research of the origin of condensed matter because they retain the original state of the metal bonds. Also, knowledge about the transition from organometallic complexes to a nanoclusters is important for understanding the structural evolution of the nanoclusters, particularly their nucleation mechanism. Herein, three transition-size gold nanoclusters are prepared via a controlled diphosphine-mediated top-down routine. Starting from small-size nanoclusters, three new nanoclusters including Au13(SAdm)8(L4)2(BPh4) (Au13), Au14(S-c-C6H11)10L4 (Au14), and Au16(S-c-C6H11)11LPh* (Au16) are obtained by controlled clipping on the surface and kernel of initial nanoclusters. Combining their atomically precise structures with DFT theoretical calculations, the overall atom-by-atom structural evolution process from Au12(SR)12 (0 e-) to Au18(SR)14 (4 e-) is mapped out. In addition, studies on their electronic structures show that the evolution from an organometallic complex to nanoclusters is accompanied by a dramatic decrease in the HOMO-LUMO gaps. Most importantly, the formation of the first Au-Au bond is captured in the "Au4S4 to Au5" nucleation process from Au12(SR)12 complex to the Au13 nanocluster. This work provides a deep insight into the origin of inner core in Au NCs and their structural transition relationship with metal complexes.
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Affiliation(s)
- Qinzhen Li
- Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei, Anhui 230601, China.,School of Physics and Materials Science, Anhui University, Hefei, Anhui 230601, China
| | - Baoyu Huang
- Department of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications of MOE, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Sha Yang
- Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei, Anhui 230601, China
| | - Hui Zhang
- School of Physics and Materials Science, Anhui University, Hefei, Anhui 230601, China
| | - Jinsong Chai
- Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei, Anhui 230601, China
| | - Yong Pei
- Department of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications of MOE, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Manzhou Zhu
- Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials and Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei, Anhui 230601, China
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9
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Brindle J, Nigra MM. Compensation Effect Exhibited by Gold Bimetallic Nanoparticles during CO Oxidation. ACS OMEGA 2021; 6:24269-24279. [PMID: 34568704 PMCID: PMC8459437 DOI: 10.1021/acsomega.1c04236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Indexed: 06/13/2023]
Abstract
While CO oxidation catalyzed by gold nanoparticles has been practiced academically for several decades, there are still important discoveries to be made. One area of current interest is to pair Au with another alloying metal and observe the catalytic consequences of the presence of the other metal. In this work, TiO2-supported bimetallic Au nanoparticles are alloyed with Cu, Co, Ni, Pd, and Ru and used as catalysts for CO oxidation. Two synthetic methods for the alloys are presented: a strong electrostatic adsorption (SEA) method and a sterically demanding ligand synthesis (SDLS) method which uses triphenylphosphine (TPP) as the ligand. The catalytic performance of the materials synthesized with the SEA and SDLS methods is compared in CO oxidation. The results indicate that the materials tested present an enthalpy-entropy compensation effect. Interestingly, both the enthalpy of activation, ΔH ‡, and the entropy of activation, ΔS ‡, generally decrease with particle size. AuCo and AuRu materials exhibit a decrease in the overall activity as compared to Au and the other Au alloys when synthesized via SEA. Au face-centered-cubic alloys AuCu, AuNi, and AuPd prepared via SEA show an improvement in activity compared to monometallic Au in our reaction conditions. In situ diffuse reflectance infrared Fourier transform spectroscopy presents two distinct regions for Au bimetallics where AuCo and AuRu show peak positions in the region of 2070-2050 cm-1, indicating a weaker interaction for AuCo and AuRu with CO when compared to that of the other alloys. For the SDLS method samples, the hypothesis is that TPP would enhance the CO oxidation rate by enhancing the charge transfer to the metallic surface. The results indicate that SDLS samples have lower CO oxidation rates and if any charge transfer occurs, it is masked by the lateral interactions of the CO π bonds and the phenyl groups of TPP.
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10
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Ligare MR, Morrison KA, Hewitt MA, Reveles JU, Govind N, Hernandez H, Baker ES, Clowers BH, Laskin J, Johnson GE. Ion Mobility Spectrometry Characterization of the Intermediate Hydrogen-Containing Gold Cluster Au 7(PPh 3) 7H 52. J Phys Chem Lett 2021; 12:2502-2508. [PMID: 33667097 DOI: 10.1021/acs.jpclett.0c03664] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We employ ion mobility spectrometry and density functional theory to determine the structure of Au7(PPh3)7H52+ (PPh3 = triphenylphosphine), which was recently identified by high mass resolution mass spectrometry. Experimental ion-neutral collision cross sections represent the momentum transfer between the ionic clusters and gas molecules averaged over the relative thermal velocities of the colliding pair, thereby providing structural insights. Theoretical calculations indicate the geometry of Au7(PPh3)7H52+ is similar to Au7(PPh3)7+, with three hydrogen atoms bridging two gold atoms and two hydrogen atoms forming single Au-H bonds. Collision-induced dissociation products observed during IMS experiments reveal that smaller hydrogen-containing clusters may be produced through fragmentation of Au7(PPh3)7H52+. Our findings indicate that hydrogen-containing species like Au7(PPh3)7H52+ act as intermediates in the formation of larger phosphine ligated gold clusters. These results advance the understanding and ability to control the mechanisms of size-selective cluster formation, which is necessary for scalable synthesis of clusters with tailored properties.
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Affiliation(s)
- Marshall R Ligare
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Kelsey A Morrison
- Department of Chemistry, Washington State University, P.O. Box 644630, Pullman, Washington 99164, United States
| | - Michael A Hewitt
- Department of Chemistry, Grinnell College, Grinnell, Iowa 50112, United States
| | - J Ulises Reveles
- Advanced Career Education (ACE) Center at Highland Springs, Highland Springs, Virginia 23075, United States
| | - Niranjan Govind
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, United States
| | - Heriberto Hernandez
- Department of Chemistry, Grinnell College, Grinnell, Iowa 50112, United States
| | - Erin S Baker
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, P.O. Box 644630, Pullman, Washington 99164, United States
| | - Julia Laskin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Grant E Johnson
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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11
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Hewitt MA, Hernández H, Johnson GE. ESI-MS Identification of the Cationic Phosphine-Ligated Gold Clusters Au 1-22: Insight into the Gold-Ligand Ratio and Abundance of Larger Clusters. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:237-246. [PMID: 33119279 DOI: 10.1021/jasms.0c00293] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Triphenylphosphine (PPh3)-ligated gold nanoclusters are valuable for a number of potential applications due to their relative ease of synthesis and usefulness in forming advanced cluster architectures. While previous studies have reported cationic PPh3-ligated gold clusters with core sizes of Au1-4, Au6-11, and Au13-14, there has not been definitive identification by mass spectrometry of many larger clusters in the Au12-25 range. Herein, we survey a polydisperse solution of cationic PPh3-ligated gold clusters using high-mass-resolution (M/ΔM = 60,000) electrospray ionization mass spectrometry (ESI-MS). To improve the sensitivity and mass resolution of larger clusters for unambiguous identification, we increased the number of scan averages and reduced the range of mass collection windows to 200 m/z, thereby mitigating potential mass and ion abundance bias resulting from smaller "building block" gold clusters that are present in much higher abundance in solution. In addition to the previously reported clusters, we identify several new species including Au5(PPh3)5+, Au12(PPh3)9HCl2+, Au15(PPh3)9Cl2+, Au16(PPh3)10Cl22+, Au17(PPh3)113+, Au18(PPh3)102+, Au19(PPh3)10Cl2+, Au20(PPh3)12H33+, Au21(PPh3)10Cl2+, and Au22(PPh3)10Cl22+, indicating that a full range of clusters between Au1-22 may be observed in a single polydisperse solution. Considering all of the clusters observed, our findings provide evidence that the Au12-14 size range is a critical transition point in cluster nucleation. While smaller clusters exhibit a 1:1 gold-to-ligand ratio, larger clusters (beginning Au12-14) feature additional gold atoms without an equal number of accompanying ligands. Our results support previous evidence in the literature indicating that the "magic number" icosahedral Au13 geometry is the smallest cluster size where a ligand-less central gold atom is coordinated by a complete shell of 12 surrounding ligated gold atoms, thereby creating a stable "one-shell" cluster. Furthermore, our findings reinforce growing evidence that ligands may be used to actively direct gold cluster size and abundance during synthesis. While for PPh3-ligated systems the most abundant species are Au6-9 clusters, we find that for related methyldiphenylphosphine (PPh2Me) and dimethylphenylphosphine (PPhMe2)-ligated systems the most abundant cluster sizes are Au10-11 and Au12-14, respectively. Together, we demonstrate that reducing the range of m/z collection windows and increasing the number of scan averages dramatically improves instrument sensitivity for cationic gold clusters, enabling thorough characterization of polydisperse solutions that is not possible using conventional techniques.
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Affiliation(s)
- Michael A Hewitt
- Department of Chemistry, Grinnell College, 1116 Eighth Avenue, Grinnell, Iowa 50112, United States
| | - Heriberto Hernández
- Department of Chemistry, Grinnell College, 1116 Eighth Avenue, Grinnell, Iowa 50112, United States
| | - Grant E Johnson
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352, United States
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12
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Machado ES, Rodrigues NM, Costa Júnior NB, Felicíssimo VC. DFT/TDDFT investigation on the structural and optical properties of Au13L clusters. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-02587-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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13
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Burgos JC, Mejía SM, Metha GF. Effect of Charge and Phosphine Ligands on the Electronic Structure of the Au 8 Cluster. ACS OMEGA 2019; 4:9169-9180. [PMID: 31460005 PMCID: PMC6648428 DOI: 10.1021/acsomega.9b00225] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/24/2019] [Indexed: 05/07/2023]
Abstract
In this work, we use density functional theory calculations with a hybrid exchange-correlation functional and effective core pseudopotentials to determine the geometry of bare and phosphine-protected Au8 nanoclusters and characterize their electronic structure. Au8 clusters were bonded to four and eight PH3 ligands in order to evaluate the effect of ligand concentration on the electronic structure, while different positional configurations were also tried for four ligands attached to the cluster. We show that the neutral clusters become more nucleophilic as the ligands bind to the clusters at stable sites. The ground-state planar configuration of Au8 is maintained depending on the concentration and position of ligands. The effect of ionizing to the +2 charge state results in disruption of planar geometry in some cases because of inoccupation of a molecular orbital with the Au-Au bonding character. Natural bond order charge analyses showed that Au atoms oxidize upon ionization, instead of phosphine. The net positive charge makes the clusters more electrophilic with a capacity to absorb electrons from nucleophiles depending on the concentration and position of ligands and on the concentration of low-coordinated gold atoms. Besides, ionization energies and electron affinities were calculated through different mechanisms, finding that both variables are much higher for charged systems and change inversely with the concentration of ligands.
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Affiliation(s)
- Juan C. Burgos
- Programa
de Ingeniería Química, Universidad
de Cartagena, Cartagena 130015, Colombia
- Departamento
de Química, Pontificia Universidad
Javeriana, Bogotá 110231, Colombia
- E-mail: (J.C.B.)
| | - Sol M. Mejía
- Departamento
de Química, Pontificia Universidad
Javeriana, Bogotá 110231, Colombia
- E-mail: (S.M.M.)
| | - Gregory F. Metha
- Department
of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
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14
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Liu G, Pinkard A, Ciborowski SM, Chauhan V, Zhu Z, Aydt AP, Khanna SN, Roy X, Bowen KH. Tuning the electronic properties of hexanuclear cobalt sulfide superatoms via ligand substitution. Chem Sci 2018; 10:1760-1766. [PMID: 30842842 PMCID: PMC6369407 DOI: 10.1039/c8sc03862g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/01/2018] [Indexed: 11/29/2022] Open
Abstract
The electronic properties of the Co6S8L8 superatom can be tuned by changing its ligand composition while maintaining its electron count and closed shell.
Molecular clusters are attractive superatomic building blocks for creating materials with tailored properties due to their unique combination of atomic precision, tunability and functionality. The ligands passivating these superatomic clusters offer an exciting opportunity to control their electronic properties while preserving their closed shells and electron counts, which is not achievable in conventional atoms. Here we demonstrate this concept by measuring the anion photoelectron spectra of a series of hexanuclear cobalt sulfide superatomic clusters with different ratios of electron-donating and electron-withdrawing ligands, Co6S8(PEt3)6–x(CO)x (x = 0–3). We find that Co6S8(PEt3)6 has a low electron affinity (EA) of 1.1 eV, and that the successive replacement of PEt3 ligands with CO gradually shifts its electronic spectrum to lower energy and increases its EA to 1.8 eV. Density functional theory calculations reveal that the increase of EA results from a monotonic lowering of the cluster highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO). Our work provides unique insights into the electronic structure and tunability of superatomic building blocks.
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Affiliation(s)
- Gaoxiang Liu
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , USA .
| | - Andrew Pinkard
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Sandra M Ciborowski
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , USA .
| | - Vikas Chauhan
- Department of Physics , Virginia Commonwealth University , 701 W. Grace St. , Richmond , Virginia 23284 , USA .
| | - Zhaoguo Zhu
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , USA .
| | - Alexander P Aydt
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Shiv N Khanna
- Department of Physics , Virginia Commonwealth University , 701 W. Grace St. , Richmond , Virginia 23284 , USA .
| | - Xavier Roy
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Kit H Bowen
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , USA .
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15
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Ligare MR, Johnson GE, Laskin J. Observing the real time formation of phosphine-ligated gold clusters by electrospray ionization mass spectrometry. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp01402c] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Real-time monitoring of the gold cluster synthesis by electrospray ionization mass spectrometry reveals distinct formation pathways for Au8, Au9 and Au10 clusters.
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Affiliation(s)
- Marshall R. Ligare
- Physical Sciences Division
- Pacific Northwest National Laboratory
- P. O. Box 999
- Richland
- USA
| | - Grant E. Johnson
- Physical Sciences Division
- Pacific Northwest National Laboratory
- P. O. Box 999
- Richland
- USA
| | - Julia Laskin
- Physical Sciences Division
- Pacific Northwest National Laboratory
- P. O. Box 999
- Richland
- USA
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