1
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Chandrashekar P, Sardar G, Sengupta T, Reber AC, Mondal PK, Kabra D, Khanna SN, Deria P, Mandal S. Modulation of Singlet-Triplet Gap in Atomically Precise Silver Cluster-Assembled Material. Angew Chem Int Ed Engl 2024; 63:e202317345. [PMID: 38078805 DOI: 10.1002/anie.202317345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Indexed: 12/30/2023]
Abstract
Silver cluster-based solids have garnered considerable attention owing to their tunable luminescence behavior. While surface modification has enabled the construction of stable silver clusters, controlling interactions among clusters at the molecular level has been challenging due to their tendency to aggregate. Judicious choice of stabilizing ligands becomes pivotal in crafting a desired assembly. However, detailed photophysical behavior as a function of their cluster packing remained unexplored. Here, we modulate the packing pattern of Ag12 clusters by varying the nitrogen-based ligand. CAM-1 formed through coordination of the tritopic linker molecule and NC-1 with monodentate pyridine ligand; established via non-covalent interactions. Both the assemblies show ligand-to-metal-metal charge transfer (LMMCT) based cluster-centered emission band(s). Temperature-dependent photoluminescence spectra exhibit blue shifts at higher temperatures, which is attributed to the extent of the thermal reverse population of the S1 state from the closely spaced T1 state. The difference in the energy gap (ΔEST ) dictated by their assemblies played a pivotal role in the way that Ag12 cluster assembly in CAM-1 manifests a wider ΔEST and thus requires higher temperatures for reverse intersystem crossing (RISC) than assembly of NC-1. Such assembly-defined photoluminescence properties underscore the potential toolkit to design new cluster- assemblies with tailored optoelectronic properties.
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Affiliation(s)
- Priyanka Chandrashekar
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, 695551, India
| | - Gopa Sardar
- Department of Physics, Indian Institute of Technology Bombay Powai, Mumbai, 400076, India
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, VA-23220, USA
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA-23220, USA
| | - Pradip Kumar Mondal
- Elettra-Sincrotrone Trieste, S.S. 14 Km 163.5 in Area Science Park, Basovizza, 34149, Trieste, Italy
| | - Dinesh Kabra
- Department of Physics, Indian Institute of Technology Bombay Powai, Mumbai, 400076, India
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA-23220, USA
| | - Pravas Deria
- School of Chemical & Biomolecular Science, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL-62901, USA
| | - Sukhendu Mandal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, 695551, India
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2
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Geng L, Sengupta T, Li X, Cui C, Lin S, Xu XL, Reber AC, Khanna SN, Zheng WJ, Luo Z. Unusually High-Spin Fe 12C 12- Metallo-Carbohedrene Clusters. J Am Chem Soc 2023. [PMID: 38041728 DOI: 10.1021/jacs.3c09690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2023]
Abstract
Ferromagnets constructed from nanometals of atomic precision are important for innovative advances in information storage, energy conversion, and spintronic microdevices. Considerable success has been achieved in designing molecular magnets, which, however, are challenging in preparation and may suffer from drawbacks on the incompatibility of high stability and strong ferromagnetism. Utilizing a state-of-the-art self-developed mass spectrometer and a homemade laser vaporization source, we have achieved a highly efficient preparation of pure iron clusters, and here, we report the finding of a strongly ferromagnetic metal-carbon cluster, Fe12C12-, simply by reacting the Fen- clusters with acetylene in proper conditions. The unique stability of this ferromagnetic Fe12C12- cluster is rooted in a plumb-bob structure pertaining to Jahn-Teller distortion. We classify Fe12C12- as a new member of metallo-carbohedrenes and elucidate its structural stability mechanism as well as its soft-landing deposition and magnetization measurements, providing promise for the exploration of potential applications.
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Affiliation(s)
- Lijun Geng
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Xilong Li
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chaonan Cui
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Shiquan Lin
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xi-Ling Xu
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Wei-Jun Zheng
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhixun Luo
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Science, University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Das AK, Biswas S, Kayal A, Reber AC, Bhandary S, Chopra D, Mitra J, Khanna SN, Mandal S. Two-Dimensional Silver-Chalcogenolate-Based Cluster-Assembled Material: A p-type Semiconductor. Nano Lett 2023; 23:8923-8931. [PMID: 37725097 DOI: 10.1021/acs.nanolett.3c02269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
We have synthesized and characterized a new two-dimensional honeycomb architecture resembling a single-layer of atomically precise silver cluster-assembled material (CAM), [Ag12(StBu)6(CF3COO)6(4,4'-azopyridine)3] (Ag12-azo-bpy). The interlayer noncovalent van der Waals interactions within the single-crystals were successfully disrupted, leading to the creation of this unique structure. The optimized Ag12-azo-bpy CAM demonstrates a valence band that is localized on the Ag12 cluster node situated near the Fermi energy level. This localization induces electron injection from the linker to the cluster node, facilitating efficient charge transportation along the plane. Exploiting this single-layer structure as a distinctive platform for p-type channel material, it was employed in a field-effect transistor configuration. Remarkably, the transistor exhibits a high hole mobility of 1.215 cm2 V-1 s-1 and an impressive ON/OFF current ratio of ∼4500 at room-temperature.
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Affiliation(s)
- Anish Kumar Das
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Sourav Biswas
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Arijit Kayal
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Subhrajyoti Bhandary
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Deepak Chopra
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Joy Mitra
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Sukhendu Mandal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
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4
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Ward AFM, Reber AC, Khanna SN. Periodic Trends in the Infrared and Optical Absorption Spectra of Metal Chalcogenide Clusters. J Phys Chem A 2023; 127:38-45. [PMID: 36548146 DOI: 10.1021/acs.jpca.2c05955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We have investigated the optical absorption, infrared spectra, binding energies, and other cluster properties to investigate whether periodic trends can be observed in the electronic structure of transition metal chalcogenide clusters ligated with CO ligands. Our studies demonstrate the existence of several periodic trends in the properties of pure and mixed octahedral metal chalcogenide clusters, TM6Se8(CO)6 (TM = W-Pt). We find that octahedral metal chalcogenide clusters with 96, 100, and 114 valence electrons have larger excitation energies, consistent with these clusters having closed electronic shells. Periodic trends were observed in the infrared spectra, with the CO bond stretch having the highest energy at 100 and 114 valence electrons due to the closed electronic shell minimizing back-bonding with the CO molecule. A periodic trend in the antisymmetric TM-C stretch was also observed, with the vibrational energy increasing as the valence electron count increased. This is due to decrease in the TM-C bond length, resulting in a larger force constant. These results reveal that periodic trends seen earlier in simple or noble-metal clusters can be observed in symmetric transition metal chalcogenide clusters, showing that the superatom concept in metal chalcogenide clusters goes beyond electronic excitations, and can be seen in other observable properties.
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Affiliation(s)
- Alain F M Ward
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia23284-2000, United States
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia23284-2000, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia23284-2000, United States
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5
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Reber AC, Sengupta T, Bista D, Khanna SN. Magic Numbers in Octahedral Ligated Metal-Chalcogenide Superatoms. Inorg Chem 2022; 61:16003-16008. [PMID: 36149274 DOI: 10.1021/acs.inorgchem.2c02361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The attainment of the superatomic state offers a unifying framework for the periodic classification of atomic clusters. Metallic clusters attain the superatomic state via the confined nearly free electron gas model that leads to groupings of quantum states marked by radial and angular momentum quantum numbers. We examine ligated octahedral metal-chalcogenide clusters where the nearly free electron gas model is invalid; however, the high symmetry can also lead to the bunching of electronic states. For octahedral TM6E8L6 clusters (TM = transition metal; E = chalcogen; L = ligand), the electronic shells are filled for valence electron counts of 96, 100, and 114 electrons. These magic electron counts are marked by large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, high ionization energies, and low electron affinity─all classic signatures of the superatomic state. We also find that clusters with electron counts differing from the magic counts show periodic patterns reminiscent of those observed in the periodic table of elements.
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Affiliation(s)
- Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
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6
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Biswas S, Das AK, Reber AC, Biswas S, Bhandary S, Kamble VB, Khanna SN, Mandal S. The New Ag-S Cluster [Ag 50S 13(S tBu) 20][CF 3COO] 4 with a Unique hcp Ag 14 Kernel and Ag 36 Keplerian-Shell-Based Structural Architecture and Its Photoresponsivity. Nano Lett 2022; 22:3721-3727. [PMID: 35499472 DOI: 10.1021/acs.nanolett.2c00609] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In metal nanoclusters (NCs), the kernel geometry and the nature of the surface protecting ligands are very crucial for their structural stability and properties. The synthesis and structural elucidation of Ag NCs is challenging because the zerovalent oxidation state of Ag is very reactive and prone to oxidization. Here, we report the NC [Ag50S13(StBu)20][CF3COO]4 with a hexagonal close-packed (hcp) cagelike Ag14 kernel. A truncated cubic shell and an octahedral shell encapsulate the hcp-layered kernel via an interstitial S2- anionic shell to form an Ag36 Keplerian outer shell of the NC. A theoretical study indicates the stability of this NC in its 4+ charge state and the charge distribution between the kernel and Keplerian shell. The unprecedented electronic structure facilitates its application toward sustainable photoresponse properties. The new insights into this novel Ag NC kernel and Keplerian shell structure may pave the way to understanding the unique structure and developing electronic structure-based applications.
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Affiliation(s)
- Sourav Biswas
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Kerala 695551, India
| | - Anish Kumar Das
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Kerala 695551, India
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Soumya Biswas
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Kerala 695551, India
| | - Subhrajyoti Bhandary
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Kerala 695551, India
| | - Vinayak B Kamble
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Kerala 695551, India
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Sukhendu Mandal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Kerala 695551, India
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7
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Bista D, Aydt AP, Anderton KJ, Paley DW, Betley TA, Reber AC, Chauhan V, Bartholomew AK, Roy X, Khanna SN. High-Spin Superatom Stabilized by Dual Subshell Filling. J Am Chem Soc 2022; 144:5172-5179. [PMID: 35289175 DOI: 10.1021/jacs.2c00731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Quantum confinement in small symmetric clusters leads to the bunching of electronic states into closely packed shells, enabling the classification of clusters with well-defined valences as superatoms. Like atoms, superatomic clusters with filled shells exhibit enhanced electronic stability. Here, we show that octahedral transition-metal chalcogenide clusters can achieve filled shell electronic configurations when they have 100 valence electrons in 50 orbitals or 114 valence electrons in 57 orbitals. While these stable clusters are intrinsically diamagnetic, we use our understanding of their electronic structures to theoretically predict that a cluster with 107 valence electrons would uniquely combine high stability and high-spin magnetic moment, attained by filling a majority subshell of 57 electrons and a minority subshell of 50 electrons. We experimentally demonstrate this predicted stability, high-spin magnetic moment (S = 7/2), and fully delocalized electronic structure in a new cluster, [NEt4]5[Fe6S8(CN)6]. This work presents the first computational and experimental demonstration of the importance of dual subshell filling in transition-metal chalcogenide clusters.
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Alexander P Aydt
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Kevin J Anderton
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Daniel W Paley
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Theodore A Betley
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Vikas Chauhan
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | | | - Xavier Roy
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
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8
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Shen J, He H, Sengupta T, Bista D, Reber AC, Pandey R, Khanna SN. Electron transport properties of PAl 12-based cluster complexes. Nanoscale Adv 2021; 3:6888-6896. [PMID: 36132360 PMCID: PMC9418132 DOI: 10.1039/d1na00355k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 09/10/2021] [Indexed: 06/15/2023]
Abstract
The electronic transport properties of PAl12-based cluster complexes are investigated by density functional theory (DFT) in combination with the non-equilibrium Green's function (NEGF) method. Joining two PAl12 clusters via a germanium linker creates a stable semiconducting complex with a large HOMO-LUMO gap. Sequential attachment of an electron-donating ligand, N-ethyl-2-pyrrolidone, to one of the two linked clusters results in the shifting of the electronic spectrum of the ligated cluster while the energy levels of the unligated cluster are mostly unchanged. Using this approach, one can eventually align the HOMO of the ligated cluster to the LUMO of the non-ligated cluster, thereby significantly reducing the HOMO-LUMO gap of the complex. As a result, the transport properties of the complex are highly dependent on the number of attached ligands. Although a single ligand is observed to generally decrease the current, the inclusion of two or more ligands shows a significant increase in the amount of current at most voltages. The resulting increase of the current can be attributed to two factors, first the reduction in the HOMO-LUMO gap due to ligand attachment which has moved the transmission orbitals into the bias window. Secondly, when two or more ligands are attached to the complex, the HOMOs become delocalized across the scattering region, and this significantly enhances the currents.
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Affiliation(s)
- John Shen
- Department of Physics and Astronomy, Valparaiso University Valparaiso Indiana 46383 USA
| | - Haiying He
- Department of Physics and Astronomy, Valparaiso University Valparaiso Indiana 46383 USA
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
| | - Ravindra Pandey
- Department of Physics, Michigan Technological University Houghton Michigan 49931 USA
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
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9
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Bista D, Sengupta T, Reber AC, Khanna SN. Interfacial magnetism in a fused superatomic cluster [Co 6Se 8(PEt 3) 5] 2. Nanoscale 2021; 13:15763-15769. [PMID: 34528648 DOI: 10.1039/d1nr00876e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
An isolated Co6Se8(PEt3)6 cluster is non-magnetic; however, we find that a magnetic unit can be formed by fusing two Co6Se8(PEt3)5 superatoms into a [Co6Se8(PEt3)5]2 dimer. Theoretical studies indicate that the dumbbell-shaped [Co6Se8(PEt3)5]2 dimer has a spin moment of 2μB, and the spin density is primarily localized at the interfacial Co-sites where two clusters are fused into a dimer. The dimer has a low ionization energy of 4.17 eV, allowing the dimer to donate charge to C70 during the formation of a cluster assembled material, as seen in recent experiments by Nuckolls and co-workers. The donation of charge causes the dimer's magnetic moment to drop from 2μB to 1μB. We hypothesize that adding electrons to the dimer, such as doping impurities to the crystal lattice, may enhance the magnetic moment by neutralizing the charged cluster. This reveals a strategy for stabilizing magnetic moments in ligated cluster assemblies.
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
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10
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Khanna SN, Reber AC, Bista D, Sengupta T, Lambert R. The superatomic state beyond conventional magic numbers: Ligated metal chalcogenide superatoms. J Chem Phys 2021; 155:120901. [PMID: 34598575 DOI: 10.1063/5.0062582] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The field of cluster science is drawing increasing attention due to the strong size and composition-dependent properties of clusters and the exciting prospect of clusters serving as the building blocks for materials with tailored properties. However, identifying a unifying central paradigm that provides a framework for classifying and understanding the diverse behaviors is an outstanding challenge. One such central paradigm is the superatom concept that was developed for metallic and ligand-protected metallic clusters. The periodic electronic and geometric closed shells in clusters result in their properties being based on the stability they gain when they achieve closed shells. This stabilization results in the clusters having a well-defined valence, allowing them to be classified as superatoms-thus extending the Periodic Table to a third dimension. This Perspective focuses on extending the superatomic concept to ligated metal-chalcogen clusters that have recently been synthesized in solutions and form assemblies with counterions that have wide-ranging applications. Here, we illustrate that the periodic patterns emerge in the electronic structure of ligated metal-chalcogenide clusters. The stabilization gained by the closing of their electronic shells allows for the prediction of their redox properties. Further investigations reveal how the selection of ligands may control the redox properties of the superatoms. These ligated clusters may serve as chemical dopants for two-dimensional semiconductors to control their transport characteristics. Superatomic molecules of multiple metal-chalcogen superatoms allow for the formation of nano-p-n junctions ideal for directed transport and photon harvesting. This Perspective outlines future developments, including the synthesis of magnetic superatoms.
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Affiliation(s)
- Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Ryan Lambert
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
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11
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Das AK, Maity S, Sengupta T, Bista D, Reber AC, Patra A, Khanna SN, Mandal S. One-Dimensional Silver-Thiolate Cluster-Assembly: Effect of Argentophilic Interactions on Excited-State Dynamics. J Phys Chem Lett 2021; 12:2154-2159. [PMID: 33626284 DOI: 10.1021/acs.jpclett.0c03728] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report the synthesis, crystal structure, and electronic structure calculations of a one-dimensional silver-thiolate cluster-assembled and its ultrafast spectroscopic investigation. Experiments and theory find the material to have a significant gap as the HOMO-LUMO absorption corresponds to 2.69 eV, and the defect-free structure is calculated to have a gap of 2.82 eV. Cluster models demonstrate that the gap energy is length-dependent. Theoretical studies identify a nonbonding metallophilic interaction that exists between two Ag atoms in adjacent strings that helps to stabilize the chain structure. Transient absorption spectroscopy reveals that the electron dynamics is a mixture of the behavior of cluster and nanoparticle, with the material having a 346 fs ground-state relaxation like a cluster, and the electron dynamics is dominated by electron-phonon coupling with a decay time of 1.5 ps, unlike the isolated cluster whose decay is mostly radiative.
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Affiliation(s)
- Anish Kumar Das
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Subarna Maity
- School of Materials Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, WB 700032, India
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Amitava Patra
- School of Materials Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, WB 700032, India
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Sukhendu Mandal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
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12
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
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13
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Anumula R, Reber AC, An P, Cui C, Guo M, Wu H, Luo Z, Khanna SN. Ligand accommodation causes the anti-centrosymmetric structure of Au 13Cu 4 clusters with near-infrared emission. Nanoscale 2020; 12:14801-14807. [PMID: 32627782 DOI: 10.1039/d0nr02448a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We synthesized an [Au13Cu4(PPh3)4(SPy)8]+ nanocluster co-capped by phosphine and thiolate ligands. Interestingly, this Au13Cu4 cluster corresponds to an anti-centrosymmetric structure with the four copper atoms coordinated to the mixed ligands on the same side of the Au13 icosahedron, which is in sharp contrast to the [Au13Cu4(PPh2Py)4(SPhtBu)8]+ and [Au13Cu2(PPh3)6(SPy)6]+ clusters which possess highly symmetric structures with well-separated Cu adatoms. Both [Au13Cu4(PPh3)4(SPy)8]+ and [Au13Cu2(PPh3)6(SPy)6]+ clusters correspond to 8 valence electron superatoms with large HOMO-LUMO gaps, respectively. The difference in structure is rooted in the nature of the mixed ligands, with the bidentate SPy binding strongly to Cu on both binding sites (-N-Cu and Au-SR-Cu) leading to the co-linking of adjacent Cu atoms, while the bidentate PPh2Py binds Cu on one site and Au on the other giving rise to a separation of the Cu atoms even in the presence of relatively higher monomer concentration. Both [Au13Cu4(PPh3)4(SPy)8]+ and [Au13Cu2(PPh3)6(SPy)6]+ display emissions in the near-IR regions. TD-DFT calculations reproduce the spectroscopic results with specified excited states, shedding light on the geometric and electronic behaviors of the ligand-protected Au13Mx clusters.
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Affiliation(s)
- Rajini Anumula
- Beijing National Laboratory for Molecular Sciences (BNLMS) and State Key Laboratory for Structural Chemistry of Unstable and Stable Species, and Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.
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14
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Bista D, Chauhan V, Sengupta T, Reber AC, Khanna SN. A ligand-induced homojunction between aluminum-based superatomic clusters. Nanoscale 2020; 12:12046-12056. [PMID: 32469025 DOI: 10.1039/d0nr02611e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A superatomic molecule formed by joining two metallic clusters linked by an organometallic bridge can behave like a semiconductor and the addition of ligands can induce a significant energy level shift across an inter-cluster homojunction. This shift is induced by the N-ethyl-2-pyrrolidone ligands, and the placement of the ligands strongly affects the direction of the dipole moment, including the case where the dipole moment is parallel to the cluster interface. This computational study provides an alternative strategy for constructing nanometer-scale electronic interfaces between clusters mimicking semiconductor motifs. The semiconducting features in the PAl12 clusters emerge from the grouping of the quantum states in a confined nearly free electron gas that creates a substantial energy gap. An organometallic Ge(CH3)2(CH2)2 bridge links the clusters while maintaining the cluster's electronic shell structure. The amount of level shifting between the bridged clusters can be changed by controlling the number of ligands. Attaching multiple ligands can result in a broken gap energy alignment in which the HOMO level of one cluster is aligned with the LUMO level of the other bridged cluster. Furthermore, the singly ligated bridged superatomic molecule is found to exhibit promising features to separate the electron-hole pairs for photovoltaic applications.
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
| | - Vikas Chauhan
- Ramjas College, University of Delhi, Delhi-110007, India
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
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15
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Abstract
Traditional p-n junctions used for photovoltaics require an interface where a light induced electron-hole pair is separated by an electric field. Developing alternative strategies for forming strong internal electric fields for electron-hole pair separation offers the possibility for better performance. We demonstrate that fusing two superatomic clusters with donor/acceptor ligands on opposite sides of the cluster leads to such a strong internal electric field. In two fused metal-chalcogenide Re6S8Cl2(L)4 clusters with donor PMe3 ligands and acceptor CO ligands on the opposite sides of the fused clusters, the electronic levels undergo shifts analogous to band bending in traditional p-n junctions. The fused cluster has a large dipole moment, and an optical spectrum that strongly absorbs excitation above the HOMO-LUMO gap of the fused clusters, but is optically very weak for the lowest energy excitation that can lead to electron-hole pair recombination. This is because the electron is localized on the CO portion of the fused cluster, while the electron-hole pair is localized on the PMe3 side of the cluster. It is shown that the electronic states localized on each side of the cluster can be aligned/misaligned by applying a voltage in different directions, offering diode like characteristics.
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Affiliation(s)
- Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23220, USA.
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16
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Zhang H, Reber AC, Geng L, Rabayda D, Wu H, Luo Z, Yao J, Khanna SN. Formation of Al
+
(C
6
H
6
)
13
: The Origin of Magic Number in Metal–Benzene Clusters Determined by the Nature of the Core. CCS Chem 2019. [DOI: 10.31635/ccschem.019.20190033] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Hanyu Zhang
- Beijing National Laboratory of Molecular sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, (China)
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, (United States)
| | - Lijun Geng
- Beijing National Laboratory of Molecular sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, (China)
| | - Daniel Rabayda
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, (United States)
| | - Haiming Wu
- Beijing National Laboratory of Molecular sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, (China)
| | - Zhixun Luo
- Beijing National Laboratory of Molecular sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, (China)
| | - Jiannian Yao
- Beijing National Laboratory of Molecular sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, (China)
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, (United States)
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Armstrong A, Zhang H, Reber AC, Jia Y, Wu H, Luo Z, Khanna SN. Al Valence Controls the Coordination and Stability of Cationic Aluminum–Oxygen Clusters in Reactions of Aln+ with Oxygen. J Phys Chem A 2019; 123:7463-7469. [DOI: 10.1021/acs.jpca.9b05646] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Albert Armstrong
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Hanyu Zhang
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Yuhan Jia
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Haiming Wu
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Zhixun Luo
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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Abstract
Electronic stability in aluminum clusters is typically associated with either closed electronic shells of delocalized electrons or a +3 oxidation state of aluminum. To investigate whether there are alternative routes toward electronic stability in aluminum oxide clusters, we used theoretical methods to examine the geometric and electronic structure of Al nO m (2 ≤ n ≤ 7; 1 ≤ m ≤ 10) clusters. Electronically stable clusters with large HOMO-LUMO (highest occupied molecular orbital and lowest unoccupied molecular orbital) gaps were identified and could be grouped into two categories. (1) Al2 nO3 n clusters with a +3 oxidation state on the aluminum and (2) planar clusters including Al4O4, Al5O3, Al6O5, and Al6O6. The structures of the planar clusters have external Al atoms bound to a single O atom. Their electronic stability is explained by the multiple-valence Al sites, with the internal Al atoms having an oxidation state of +3, whereas the external Al atoms have an oxidation state of +1.
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Affiliation(s)
- Albert Armstrong
- Department of Physics , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
| | - Arthur C Reber
- Department of Physics , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
| | - Shiv N Khanna
- Department of Physics , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
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Jash M, Reber AC, Ghosh A, Sarkar D, Bodiuzzaman M, Basuri P, Baksi A, Khanna SN, Pradeep T. Preparation of gas phase naked silver cluster cations outside a mass spectrometer from ligand protected clusters in solution. Nanoscale 2018; 10:15714-15722. [PMID: 30094450 DOI: 10.1039/c8nr04146f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Gas phase clusters of noble metals prepared by laser desorption from the bulk have been investigated extensively in a vacuum using mass spectrometry. However, such clusters have not been known to exist under ambient conditions to date. In our previous work, we have shown that in-source fragmentation of ligands can be achieved starting from hydride and phosphine co-protected silver clusters leading to naked silver clusters inside a mass spectrometer. In a recent series of experiments, we have found that systematic desorption of ligands of the monolayer protected atomically precise silver cluster can also occur in the atmospheric gas phase. Here, we present the results, wherein the [Ag18H16(TPP)10]2+ (TPP = triphenylphosphine) cluster results in the formation of the naked cluster, Ag17+ along with Ag18H+ without mass selection, outside the mass spectrometer, in air. These cationic naked metal clusters are prepared by passing electrosprayed ligand protected clusters through a heated tube, in the gas phase. Reactions with oxygen suggest Ag17+ to be more reactive than Ag18H+, in agreement with their electronic structures. The more common thiolate protected clusters produce fragments of metal thiolates under identical processing conditions and no naked clusters were observed.
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Affiliation(s)
- Madhuri Jash
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India.
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21
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Chauhan V, Reber AC, Khanna SN. Strong lowering of ionization energy of metallic clusters by organic ligands without changing shell filling. Nat Commun 2018; 9:2357. [PMID: 29907744 PMCID: PMC6003947 DOI: 10.1038/s41467-018-04799-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 05/08/2018] [Indexed: 11/09/2022] Open
Abstract
Alkali atoms have unusually low ionization energies because their electronic structures have an excess electron beyond that of a filled electronic shell. Quantum states in metallic clusters are grouped into shells similar to those in atoms, and clusters with an excess electron beyond a closed electronic may also exhibit alkali character. This approach based on shell-filling is the way alkali species are formed as explained by the periodic table. We demonstrate that the ionization energy of metallic clusters with both filled and unfilled electronic shells can be substantially lowered by attaching ligands. The ligands form charge transfer complexes where the electronic spectrum is lifted via crystal field like effect. We demonstrate that the effect works for the weakly bound ligand, N-ethyl-2-pyrrolidone (EP = C6H11NO), and that the effect leads to a dramatic lowering of the ionization energy independent of the shell occupancy of the cluster.
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Affiliation(s)
- Vikas Chauhan
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
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22
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Yang Y, Reber AC, Gilliland SE, Castano CE, Gupton BF, Khanna SN. More than just a support: Graphene as a solid-state ligand for palladium-catalyzed cross-coupling reactions. J Catal 2018. [DOI: 10.1016/j.jcat.2018.01.027] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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24
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Biltek SR, Reber AC, Khanna SN, Sen A. Complete Ag4M2(DMSA)4 (M = Ni, Pd, Pt, DMSA = Dimercaptosuccinic Acid) Cluster Series: Optical Properties, Stability, and Structural Characterization. J Phys Chem A 2017; 121:5324-5331. [DOI: 10.1021/acs.jpca.7b04669] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Scott R. Biltek
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Arthur C. Reber
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Shiv N. Khanna
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Ayusman Sen
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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25
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Affiliation(s)
- Cameron J. Grover
- Department of Physics, Virginia Commonwealth University, 701 West Grace Street, Richmond, Virginia 23220, USA
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, 701 West Grace Street, Richmond, Virginia 23220, USA
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, 701 West Grace Street, Richmond, Virginia 23220, USA
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26
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Blades WH, Reber AC, Khanna SN, López-Sosa L, Calaminici P, Köster AM. Evolution of the Spin Magnetic Moments and Atomic Valence of Vanadium in VCu x+, VAg x+, and VAu x+ Clusters (x = 3-14). J Phys Chem A 2017; 121:2990-2999. [PMID: 28350450 DOI: 10.1021/acs.jpca.7b01030] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The atomic structures, bonding characteristics, spin magnetic moments, and stability of VCux+, VAgx+, and VAux+ (x = 3-14) clusters were examined using density functional theory. Our studies indicate that the effective valence of vanadium is size-dependent and that at small sizes some of the valence electrons of vanadium are localized on vanadium, while at larger sizes the 3d orbitals of the vanadium participate in metallic bonding eventually quenching the spin magnetic moment. The electronic stability of the clusters may be understood through a split-shell model that partitions the valence electrons in either a delocalized shell or localized on the vanadium atom. A molecular orbital analysis reveals that in planar clusters the delocalization of the 3d orbital of vanadium is enhanced when surrounded by gold due to enhanced 6s-5d hybridization. Once the clusters become three-dimensional, this hybridization is reduced, and copper most readily delocalizes the vanadium's valence electrons. By understanding these unique features, greater insight is offered into the role of a host material's electronic structure in determining the bonding characteristics and stability of localized spin magnetic moments in quantum confined systems.
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Affiliation(s)
- William H Blades
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States.,Department of Materials Science and Engineering, University of Virginia , Charlottesville, Virginia 22904, United States
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Luis López-Sosa
- Departamento de Química, CINVESTAV , Av. Instituto Politécnico Nacional 2508, A.P. 14-740, México D.F. 07000, Mexico
| | - Patrizia Calaminici
- Departamento de Química, CINVESTAV , Av. Instituto Politécnico Nacional 2508, A.P. 14-740, México D.F. 07000, Mexico
| | - Andreas M Köster
- Departamento de Química, CINVESTAV , Av. Instituto Politécnico Nacional 2508, A.P. 14-740, México D.F. 07000, Mexico
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27
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Abstract
The relative role of electronic and geometric effects on the stability of clusters has been a contentious topic for quite some time, with the focus on electronic structure generally gaining the upper hand. In this Account, we hope to demonstrate that both electronic shell filling and geometric shell filling are necessary concepts for an intuitive understanding of the reactivity of metal clusters. This work will focus on the reactivity of aluminum based clusters, although these concepts may be applied to clusters of different metals and ligand protected clusters. First we highlight the importance of electronic shell closure in the stability of metallic clusters. Quantum confinement in small compact metal clusters results in the bunching of quantum states that are reminiscent of the electronic shells in atoms. Clusters with closed electronic shells and large HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) gaps have enhanced stability and reduced reactivity with O2 due to the need for the cluster to accommodate the spin of molecular oxygen during activation of the molecule. To intuitively understand the reactivity of clusters with protic species such as water and methanol, geometric effects are needed. Clusters with unsymmetrical structures and defects usually result in uneven charge distribution over the surface of the cluster, forming active sites. To reduce reactivity, these sites must be quenched. These concepts can also be applied to ligand protected clusters. Clusters with ligands that are balanced across the cluster are less reactive, while clusters with unbalanced ligands can result in induced active sites. Adatoms on the surface of a cluster that are bound to a ligand result in an activated adatom that reacts readily with protic species, offering a mechanism by which the defects will be etched off returning the cluster to a closed geometric shell. The goal of this Account is to argue that both geometric and electronic shell filling concepts serve as valuable organizational principles that explain a wide variety of phenomena in the reactivity of clusters. These concepts help to explain the fundamental interactions that allow for specific clusters to be described as superatoms. Superatoms are clusters that exhibit a well-defined valence. A superatom cluster's properties may be intuitively understood and predicted based on the energy gained when the cluster obtains its optimal electronic and geometric structure. This concept has been found to be a unifying principle among a wide variety of metal clusters ranging from free aluminum clusters to ligand protected noble metal clusters and even metal-chalcogenide ligand protected clusters. Thus, the importance of electronic and geometric shell closing concepts supports the superatom concept, because the properties of certain clusters with well-defined valence are controlled by the stability that is enhanced when they retain their closed electronic and geometric shells.
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Affiliation(s)
- Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284, United States
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Chauhan V, Reber AC, Khanna SN. Metal Chalcogenide Clusters with Closed Electronic Shells and the Electronic Properties of Alkalis and Halogens. J Am Chem Soc 2017; 139:1871-1877. [DOI: 10.1021/jacs.6b09416] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Vikas Chauhan
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia, United States
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29
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Affiliation(s)
- Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Vikas Chauhan
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
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Abstract
The role of carbon monoxide ligands on the magnetic moment of Co6Se8(CO)n clusters, n = 0–6 was investigated to better understand the interplay between the electronic structure of metal chalcogenide clusters and their ligands.
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Affiliation(s)
- Vikas Chauhan
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | - Arthur C. Reber
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | - Shiv N. Khanna
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
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31
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Yang Y, Castano CE, Gupton BF, Reber AC, Khanna SN. A fundamental analysis of enhanced cross-coupling catalytic activity for palladium clusters on graphene supports. Nanoscale 2016; 8:19564-19572. [PMID: 27833943 DOI: 10.1039/c6nr06793j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Combining the recyclability of heterogeneous catalysts with the high activity of ligated homogeneous catalysts for the production of complex organic molecules is a cardinal goal of catalyst development. We have investigated the activity of ultra-fine Pd clusters bound to vacancy defective sites in graphene and found that the defective graphene both serves as a support to stabilize the recyclable catalyst, and also functions as a ligand enhancing the catalytic activity. In this paper, we report computational and experimental results that provide insights into the nature of the interfacial interactions between metal nanoparticles and defect sites on the graphene surface. Theoretical investigations reveal that while the vacancy/void sites on the graphene surface strongly bind to the metal clusters providing enhanced stability against leaching, graphene also serves as a reservoir of electron density that effectively reduces the activation energy of specific steps within the catalytic cycle. Furthermore, multiple experimental methods were used to unambiguously demonstrate that these cross-coupling reactions are occurring at the Pd/G catalyst surface.
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Affiliation(s)
- Y Yang
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - C E Castano
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - B Frank Gupton
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - A C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - S N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.
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32
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33
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Affiliation(s)
- Vikas Chauhan
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
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34
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Luo Z, Reber AC, Jia M, Blades WH, Khanna SN, Castleman AW. What determines if a ligand activates or passivates a superatom cluster? Chem Sci 2016; 7:3067-3074. [PMID: 29997798 PMCID: PMC6005155 DOI: 10.1039/c5sc04293c] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/26/2016] [Indexed: 11/29/2022] Open
Abstract
Quantum confinement in small metal clusters leads to a bunching of states into electronic shells reminiscent of shells in atoms, enabling the classification of clusters as superatoms.
Quantum confinement in small metal clusters leads to a bunching of states into electronic shells reminiscent of shells in atoms, enabling the classification of clusters as superatoms. The addition of ligands tunes the valence electron count of metal clusters and appears to serve as protecting groups preventing the etching of the metallic cores. Through a joint experimental and theoretical study of the reactivity of methanol with aluminum clusters ligated with iodine, we find that ligands enhance the stability of some clusters, however in some cases the electronegative ligand may perturb the charge density of the metallic core generating active sites that can lead to the etching of the cluster. The reactivity is driven by Lewis acid and Lewis base active sites that form through the selective positioning of the iodine and the structure of the aluminum core. This study enriches the general knowledge on clusters including offering insight into the stability of ligand protected clusters synthesized via wet chemistry.
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Affiliation(s)
- Zhixun Luo
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species , Institute of Chemistry , Chinese Academy of Sciences , Beijing , 100190 , China . .,Departments of Chemistry and Physics , The Pennsylvania State University , University Park , PA 16802 , USA .
| | - Arthur C Reber
- Department of Physics , Virginia Commonwealth University , Richmond , VA 23284 , USA .
| | - Meiye Jia
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species , Institute of Chemistry , Chinese Academy of Sciences , Beijing , 100190 , China .
| | - William H Blades
- Department of Physics , Virginia Commonwealth University , Richmond , VA 23284 , USA .
| | - Shiv N Khanna
- Department of Physics , Virginia Commonwealth University , Richmond , VA 23284 , USA .
| | - A W Castleman
- Departments of Chemistry and Physics , The Pennsylvania State University , University Park , PA 16802 , USA .
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George A, Asha KS, Reber AC, Biltek SR, Pedicini AF, Sen A, Khanna SN, Mandal S. Atom precise platinum-thiol crowns. Nanoscale 2015; 7:19448-19452. [PMID: 26486562 DOI: 10.1039/c5nr05325k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ligand stabilized water soluble Pt nanoclusters were synthesized and characterized through electrospray ionization mass spectrometry. Glutathione was used as the ligand, and Pt5(SG)10, and Pt6(SG)12 clusters were synthesized. Theoretical investigations found that these clusters do not possess a metal core, but rather are most stable in a ring structure. The clusters are stabilized through the thiol ligands forming a square planar structure around each Pt atom to form a ring. The structural elucidation was confirmed through UV/Vis and IR spectroscopy.
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Affiliation(s)
- Anu George
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala-695016, India.
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Sahoo S, Reber AC, Khanna SN. Conceptual Basis for Understanding C–C Bond Activation in Ethane by Second Row Transition Metal Carbides. J Phys Chem A 2015; 119:12855-61. [PMID: 26616749 DOI: 10.1021/acs.jpca.5b09567] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sanjubala Sahoo
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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37
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Affiliation(s)
- Marissa Baddick Abreu
- Department of Physics, Virginia Commonwealth University, 701 West Grace Street, Richmond, Virginia 23220, USA
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, 701 West Grace Street, Richmond, Virginia 23220, USA
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, 701 West Grace Street, Richmond, Virginia 23220, USA
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38
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Asha KS, Reber AC, Pedicini AF, Khanna SN, Mandal S. The Effects of Alkaline‐Earth Counterions on the Architectures, Band‐Gap Energies, and Proton Transfer of Triazole‐Based Coordination Polymers. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201403162] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- K. S. Asha
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695016, India, http://iisertvm.ac.in/~sukhendum
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA, USA
| | | | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA, USA
| | - Sukhendu Mandal
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695016, India, http://iisertvm.ac.in/~sukhendum
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39
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Affiliation(s)
- Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, USA
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, USA
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40
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Abstract
FeSi14 is stable due to its compact and symmetric cage structure highlighting the importance of geometric effects in FeSin clusters.
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Affiliation(s)
- Vikas Chauhan
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | | | - Arthur C. Reber
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | - Shiv N. Khanna
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
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41
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Ghosh R, Pedicini AF, Rao PC, Asha KS, Reber AC, Mandal S. The effect of cluster size on the optical band gap energy of Zn-based metal–organic frameworks. Dalton Trans 2015; 44:13464-8. [DOI: 10.1039/c5dt02132d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have synthesized three Metal–Organic Frameworks (MOFs) in which Zn metal ions form the secondary building unit, and 4,4′-sulfonyldibenzoic acid (SDB) serves as the ligand: [[Zn(DMF)(SDB)] (DMF), 1, [Zn3(DMF)3(SDB)3](DMF), 2 and [Zn3(OH)2(SDB)2] (DMF)2, 3, where DMF = dimethyl formamide].
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Affiliation(s)
- Raja Ghosh
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram
- Kerala
- India
| | | | - Purna Chandra Rao
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram
- Kerala
- India
| | - K. S. Asha
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram
- Kerala
- India
| | - Arthur C. Reber
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | - Sukhendu Mandal
- School of Chemistry
- Indian Institute of Science Education and Research Thiruvananthapuram
- Kerala
- India
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42
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Abstract
Understanding the bonding between silicon and transition metals is valuable for devising strategies for incorporating magnetic species into silicon. CrSi12 is the standard example of a cluster whose apparent high stability has been explained by the 18-electron rule. We critically examine the bonding and nature of stability of CrSi12 and show that its electronic structure does not conform to the 18-electron rule. Through theoretical studies, we find that CrSi12 has 16 effective valence electrons assigned to the Cr atom and an unoccupied 3dz(2) orbital. We demonstrate that the cluster's apparent stability is rooted in a crystal field-like splitting of the 3d orbitals analogous to that of square planar complexes. CrSi14 is shown to follow the 18-electron rule and exhibits all conventional markers characteristic of a magic cluster.
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Affiliation(s)
- Marissa Baddick Abreu
- Department of Physics, Virginia Commonwealth University, 1020 West Main Street, Richmond, Virginia 23284-2000, United States
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, 1020 West Main Street, Richmond, Virginia 23284-2000, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, 1020 West Main Street, Richmond, Virginia 23284-2000, United States
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43
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Smith JC, Reber AC, Khanna SN, Castleman AW. Boron substitution in aluminum cluster anions: magic clusters and reactivity with oxygen. J Phys Chem A 2014; 118:8485-92. [PMID: 24725222 DOI: 10.1021/jp501934t] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have studied the size-selective reactivity of AlnBm(-) clusters m = 1,2 with O2 to investigate the effect of congener substitution in energetic aluminum clusters. Mixed-metal clusters offer an additional strategy for tuning the electronic and geometric structure of clusters and by substituting an atom with a congener; we may investigate the effect of structural changes in clusters with similar electronic structures. Using a fast-flow tube mass spectrometer, we formed aluminum boride cluster anions and exposed them to molecular oxygen. We found multiple stable species with Al12B(-) and Al11B2(-) being highly resistant to reactivity with oxygen. These clusters behave in a similar manner as Al13(-), which has previously been found to be stable in oxygen because of its icosahedral geometry and its filled electronic shell. Al13(-) and Al12B(-) have icosahedral structures, while Al11B2(-) forms a distorted icosahedron. All three of these clusters have filled electronic shells, and Al12B(-) has a larger HOMO-LUMO gap due to its compact geometry. Other cluster sizes are investigated, and the structures of the AlnB(-) series are found to have endohedrally doped B atoms, as do many of the AlnB2(-) clusters. The primary etching products are found to be a loss of two Al2O molecules, with boron likely to remain in the cluster.
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Affiliation(s)
- Jordan C Smith
- Departments of Chemistry and Physics, The Pennsylvania State University , 104 Chemistry Building, University Park, Pennsylvania 16802, United States
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44
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Affiliation(s)
- Zhixun Luo
- State
Key Laboratory for Structural Chemistry of Unstable and Stable Species,
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Departments
of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gabriel U. Gamboa
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Meiye Jia
- State
Key Laboratory for Structural Chemistry of Unstable and Stable Species,
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Arthur C. Reber
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Shiv N. Khanna
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - A. W. Castleman
- Departments
of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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45
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Medel VM, Reber AC, Chauhan V, Sen P, Köster AM, Calaminici P, Khanna SN. Nature of valence transition and spin moment in Ag(n)V(+) clusters. J Am Chem Soc 2014; 136:8229-36. [PMID: 24824084 DOI: 10.1021/ja412064c] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Evolution in the atomic structure, bonding characteristics, stability, and the spin magnetic moment of neutral and cationic AgnV clusters has been investigated using first-principles density functional approach with gradient corrected functional. It is shown that at small sizes, the V 4s states hybridize with Ag states to form 1S and 1P like superatomic orbitals, whereas the 3d states are localized on V giving the V atom an effective valence of 1 or 2. Starting from Ag8V(+), the V 3d states begin to participate in the bonding by hybridizing with the nearly free electron gas to form 1D superatomic orbitals increasing the V atom effective valence toward 5. For the cationic clusters, this changing valence results in three shell closures that lead to stable species. These occur for cationic clusters containing 5, 7, and 14 Ag atoms. The first two stable species correspond to filled 1S and 1P shells in two and three dimensions with a valence of 2 for V, whereas the closure at 14 Ag atoms correspond to filled 1S, 1P, and 1D shells with V site exhibiting a valence of 5. The transition from filled 1S and 1P shells to filled 1S, 1P, and 1D shells is confirmed by a quenching of the spin magnetic moment. The theoretical findings are consistent with the observed drops in intensity in the mass spectrum of AgnV(+) clusters after 5, 7, and 14 Ag atoms.
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Affiliation(s)
- Victor M Medel
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284-2000, United States
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46
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Biltek SR, Sen A, Pedicini AF, Reber AC, Khanna SN. Isolation and Structural Characterization of a Silver–Platinum Nanocluster, Ag4Pt2(DMSA)4. J Phys Chem A 2014; 118:8314-9. [DOI: 10.1021/jp501124q] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Scott R. Biltek
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ayusman Sen
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Anthony F. Pedicini
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Arthur C. Reber
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Shiv N. Khanna
- Department
of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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47
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Abstract
Cluster-assembled materials combine the nanoscale size and composition-dependent properties of clusters, which have highly tunable magnetic and electronic properties useful for a great variety of potential technologies. To understand the emergent properties as clusters are assembled into hierarchical materials, we have synthesized 23 cluster-assembled materials composed of As7(3-)-based motifs and different countercations and measured their band gap energies. We found that the band gap energy varies from 1.09 to 2.21 eV. In addition, we have carried out first principles electronic structure studies to identify the physical mechanisms that enable control of the band gap edges of the cluster assemblies. The choice of counterion has a profound effect on the band gap energy in ionic cluster assemblies. The top of the valence band is localized on the arsenic cluster, while the conduction band edge is located on the alkali metal counterions. Changing the counterion changes the position of the conduction band edge, enabling control of the band gap energy. We can also vary the architecture of the ionic solid by incorporating cryptates as counterions, which provide charge but are separated from the clusters by bulky ligands. Higher dimensionality typically decreases the band gap energy through band broadening; however band gap energies increased upon moving from zero-dimensional (0D) to two-dimensional (2D) assemblies. This is because internal electric fields generated by the counterion preferentially stabilize the adjacent lone pair orbitals that mark the top of the valence band. Thus, the choice of the counterion can control the position of the conduction band edge of ionic cluster assemblies. In addition, the dimensionality of the solid via internal electric fields can control the valence band edge. Through covalently linking arsenic clusters into composite building blocks, we have also been able to tune the band gap energy. We used a theoretical description based on cluster orbital theory to provide microscopic understanding of the electronic character of the composite building blocks and the observed variations in the band gap energy. Also, we have shown how dimeric linkers can be used to control the band gap energy. Lastly, we also investigated the effects of charge transfer complexes of M(CO)3 on the band gap energy.
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Affiliation(s)
- Sukhendu Mandal
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Meichun Qian
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Paul S. Weiss
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- California NanoSystems Institute, Departments of Chemistry & Biochemistry and Materials Science & Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Ayusman Sen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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48
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Pedicini AF, Reber AC, Khanna SN. The effect of sulfur covalent bonding on the electronic shells of silver clusters. J Chem Phys 2013; 139:164317. [DOI: 10.1063/1.4827091] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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49
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50
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Luo Z, Grover CJ, Reber AC, Khanna SN, Castleman AW. Probing the Magic Numbers of Aluminum–Magnesium Cluster Anions and Their Reactivity toward Oxygen. J Am Chem Soc 2013; 135:4307-13. [DOI: 10.1021/ja310467n] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Zhixun Luo
- Departments of Chemistry and
Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Cameron J. Grover
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia
23284, United States
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia
23284, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia
23284, United States
| | - A. W. Castleman
- Departments of Chemistry and
Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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