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R D, Sengupta T, Kumar D, Khanna SN. Effect of Ligand Attachment at Ag 11 for CO Oxidation: A Computational Investigation. J Phys Chem A 2023; 127:10766-10774. [PMID: 38095876 DOI: 10.1021/acs.jpca.3c04675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Heterogeneous CO oxidation is a demanding reaction at room temperature due to the high activation energy required to break the O=O bond. While several metal clusters are reported to oxidize CO successfully, they fall short of their selectivity for the reaction and recyclability. In this regard, there is a need for economic catalysts with high catalytic activity, low activation barrier, and reusability. In this study, we have investigated the catalytic activity of the neutral pristine and ligated Ag11 cluster toward CO oxidation. We investigated the attachment effect of three organic donor ligands: trimethylphosphine, triethylphosphine, and N-ethyl pyrrolidone to the Ag11 cluster. Our results show that including donor ligands on the Ag11 cluster surface can significantly reduce the barrier heights for CO oxidation. The minimum barrier heights with the system coordinated with triethylphosphine showed the lowest activation barrier of 1.06 kcal/mol compared to the high activation barrier of 14.77 kcal/mol recorded for the pristine cluster. Exploration of the reaction mechanism and charge analysis showed that the electron donor ligands activate O2 via charge donation, thereby reducing the barrier heights of CO oxidation.
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Affiliation(s)
- Deeksha R
- Department of Chemistry, Faculty of Mathematical and Physical Sciences, M.S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka 560058, India
| | - Turbasu Sengupta
- Physics Department, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284-2000, United States
| | - Deepak Kumar
- Department of Chemistry, Faculty of Mathematical and Physical Sciences, M.S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka 560058, India
| | - Shiv N Khanna
- Physics Department, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284-2000, United States
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2
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Sengupta T, Khanna SN. Converting CO 2 to formic acid by tuning quantum states in metal chalcogenide clusters. Commun Chem 2023; 6:53. [PMID: 36941466 PMCID: PMC10027883 DOI: 10.1038/s42004-023-00851-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 03/07/2023] [Indexed: 03/23/2023] Open
Abstract
The catalytic conversion of CO2 into valuable chemicals is an effective strategy for reducing its adverse impact on the environment. In this work, the formation of formic acid via CO2 hydrogenation on bare and ligated Ti6Se8 clusters is investigated with gradient-corrected density functional theory. It is shown that attaching suitable ligands (i.e., PMe3, CO) to a metal-chalcogenide cluster transforms it into an effective donor/acceptor enabling it to serve as an efficient catalyst. Furthermore, by controlling the ratio of the attached donor/acceptor ligands, it is possible to predictably alter the barrier heights of the CO2 hydrogenation reaction and, thereby, the rate of CO2 conversion. Our calculation further reveals that by using this strategy, the barrier heights of CO2 hydrogenation can be reduced to ~0.12 eV or possibly even lower, providing unique opportunities to control the reaction rates by using different combinations of donor/acceptor ligands.
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Affiliation(s)
- Turbasu Sengupta
- 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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3
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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] [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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4
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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] [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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5
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Yu F, Li J, Liu Z, Wang R, Zhu Y, Huang W, Liu Z, Wang Z. From Atomic Physics to Superatomic Physics. J CLUST SCI 2022. [DOI: 10.1007/s10876-022-02354-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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6
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Sengupta T, Khanna SN. Rational Design of Bimetallic Metal Chalcogenide Clusters for CO 2 Dissociation. J Phys Chem A 2022; 126:5702-5710. [PMID: 35973159 DOI: 10.1021/acs.jpca.2c03560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thermochemical dissociation of CO2 on pure, ligated, and mixed transition metal (W, Cu) chalcogenide clusters are investigated using the first-principles gradient-corrected density functional approach. It is shown that although the pure and ligated metal chalcogenide clusters exhibit significantly high barriers for CO2 dissociation, the computed barriers for the mixed clusters are relatively lower. The lowest barrier is obtained for the Cu3W3Se8 cluster, which shows a dramatically reduced barrier height of only 0.41 eV. Detailed analysis reveals that the substitution of W by Cu sites leads to a charge transfer from Cu to W sites, resulting in locally active W sites. The lowering of the CO2 dissociation barriers can be attributed to the facile transfer of charge from the locally active W sites and also due to the alteration of the binding energy of CO2 to the charged W sites. Our studies provide an alternate strategy to design novel thermochemical catalysts for CO2 adsorption and subsequent dissociation.
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Affiliation(s)
- Turbasu Sengupta
- 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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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] [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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Shibuta M, Inoue T, Kamoshida T, Eguchi T, Nakajima A. Al13− and B@Al12− superatoms on a molecularly decorated substrate. Nat Commun 2022; 13:1336. [PMID: 35288553 PMCID: PMC8921336 DOI: 10.1038/s41467-022-29034-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/17/2022] [Indexed: 11/20/2022] Open
Abstract
Aluminum nanoclusters (Aln NCs), particularly Al13− (n = 13), exhibit superatomic behavior with interplay between electron shell closure and geometrical packing in an anionic state. To fabricate superatom (SA) assemblies, substrates decorated with organic molecules can facilitate the optimization of cluster–surface interactions, because the molecularly local interactions for SAs govern the electronic properties via molecular complexation. In this study, Aln NCs are soft-landed on organic substrates pre-deposited with n-type fullerene (C60) and p-type hexa-tert-butyl-hexa-peri-hexabenzocoronene (HB-HBC, C66H66), and the electronic states of Aln are characterized by X-ray photoelectron spectroscopy and chemical oxidative measurements. On the C60 substrate, Aln is fixed to be cationic but highly oxidative; however, on the HB-HBC substrate, they are stably fixed as anionic Aln− without any oxidations. The results reveal that the careful selection of organic molecules controls the design of assembled materials containing both Al13− and boron-doped B@Al12− SAs through optimizing the cluster–surface interactions. Anionic aluminium clusters are promising candidates for the fabrication of superatom-assembled nanomaterials. Here, the authors report enhanced stability for Al13− and boron-doped B@Al12− on a molecularly decorated p-type organic substrate.
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9
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Li J, Cui M, Yang H, Chen J, Cheng S. Ligand-field regulated superalkali behavior of the aluminum-based clusters with distinct shell occupancy. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.02.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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10
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Hou N, Liu TT, Fang XH. Remarkable static and dynamic nonlinear optical responses of Al 13-TCNQ/F4-TCNQ complexes: a quantum chemical study. NEW J CHEM 2022. [DOI: 10.1039/d2nj04460a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Al13-TCNQ/F4-TCNQ complexes, which exhibit excellent stability and first hyperpolarizabilities, can be considered as candidates for UV and IR NLO materials.
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Affiliation(s)
- Na Hou
- Laboratory of Magnetic Molecules and Magnetic Information Materials (Ministry of Education), School of Chemistry and Material Science, Shanxi Normal University, Taiyuan, 030031, China
| | - Ting-Ting Liu
- Laboratory of Magnetic Molecules and Magnetic Information Materials (Ministry of Education), School of Chemistry and Material Science, Shanxi Normal University, Taiyuan, 030031, China
| | - Xiao-Hui Fang
- Laboratory of Magnetic Molecules and Magnetic Information Materials (Ministry of Education), School of Chemistry and Material Science, Shanxi Normal University, Taiyuan, 030031, China
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11
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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 ADVANCES 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] [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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12
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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] [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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13
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Bista D, Sengupta T, Khanna SN. Massive dipoles across the metal-semiconductor cluster interface: towards chemically controlled rectification. Phys Chem Chem Phys 2021; 23:18975-18982. [PMID: 34612436 DOI: 10.1039/d1cp02420e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An interface between a metallic cluster (MgAl12) and a semiconducting cluster (Re6Se8(PMe3)5) is shown to be marked by a massive dipole reminiscent of a dipolar layer leading to a Schottky barrier at metal-semiconductor interfaces. The metallic cluster MgAl12 with a valence electron count of 38 electrons is two electrons short of 40 electrons needed to complete its electronic shells in a superatomic model and is marked by a significant electron affinity of 2.99 eV. On the other hand, the metal-chalcogenide semiconducting cluster Re6Se8(PMe3)5, consisting of a Re6Se8 core ligated with five trimethylphosphine ligands, is highly stable in the +2 charge-state owing to its electronic shell closure, and has a low ionization energy of 3.3 eV. The composite cluster Re6Se8(PMe3)5-MgAl12 formed by combining the MgAl12 cluster through the unligated site of Re6Se8(PMe3)5 exhibits a massive dipole moment of 28.38 D resulting from a charge flow from Re6Se8(PMe3)5 to the MgAl12 cluster. The highest occupied molecular orbital (HOMO) of the composite cluster is on the MgAl12 side, which is 0.53 eV below the lowest unoccupied molecular orbital (LUMO) localized on the Re6Se8(PMe3)5 cluster, reminiscent of a Schottky barrier at metal-semiconductor interfaces. Therefore, the combination can act as a rectifier, and an application of a voltage of approximately 4.1 V via a homogeneous external electric field is needed to overcome the barrier aligning the two states: the HOMO in MgAl12 with the LUMO in Re6Se8(PMe3)5. Apart from the bias voltage, the barrier can also be reduced by attaching ligands to the metallic cluster, which provides chemical control over rectification. Finally, the fused cluster is shown to be capable of separating electron-hole pairs with minimal recombination, offering the potential for photovoltaic applications.
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
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15
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Bista D, Sengupta T, Reber AC, Khanna SN. A Magnetic Superatomic Dimer with an Intense Internal Electric Dipole Moment. J Phys Chem A 2021; 125:816-824. [DOI: 10.1021/acs.jpca.0c10262] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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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16
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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] [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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17
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Structural and Electronic Properties of Nano-brass: CuxZny (x + y = 11 − 13) Clusters. J CLUST SCI 2020. [DOI: 10.1007/s10876-019-01698-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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18
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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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19
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Zhao Y, Wang J, Huang HC, Li J, Dong XX, Chen J, Bu YX, Cheng SB. Tuning the Electronic Properties and Performance of Low-Temperature CO Oxidation of the Gold Cluster by Oriented External Electronic Field. J Phys Chem Lett 2020; 11:1093-1099. [PMID: 31967837 DOI: 10.1021/acs.jpclett.9b03794] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Conventional electronic rules, including Jellium and Wade-Mingos rules and so on, have long been successfully dedicated to design superatoms. These rules, however, rely on altering the intrinsic properties, for example, the compositions or the number of valence electrons, of clusters, which is relatively complicated and inconvenient to manipulate, especially in experiments. Herein, by employing density functional theory calculations, the oriented external electric field (OEEF) was demonstrated to possess the capability of precisely and continuously regulating the electronic properties of clusters at will, representing a novel and noninvasive methodology in constructing stable superatoms because it hardly changes the geometries of clusters. More interestingly, the active sites formed by the charge redistribution upon the introduction of an OEEF could significantly promote the catalytic performance of the low-temperature CO oxidation over clusters. Considering the convenient source of the OEEF, the findings highlighted here may boost the potential applications of superatom-assembly nanomaterials in catalysis and materials science.
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Affiliation(s)
- Yang Zhao
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
| | - Jing Wang
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
| | - Hai-Cai Huang
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
| | - Jun Li
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
| | - Xiao-Xiao Dong
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
| | - Jing Chen
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
- Suzhou Institute of Shandong University , Suzhou , Jiangsu 215123 , People's Republic of China
| | - Yu-Xiang Bu
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
- School of Chemistry and Chemical Engineering , Qufu Normal University , Qufu 273165 , People's Republic of China
| | - Shi-Bo Cheng
- School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , People's Republic of China
- Suzhou Institute of Shandong University , Suzhou , Jiangsu 215123 , People's Republic of China
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20
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Potassium iodide cluster based superhalogens and superalkalis: Theoretical calculations and experimental confirmation. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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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] [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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22
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Tkachenko NV, Sun ZM, Boldyrev AI. Record Low Ionization Potentials of Alkali Metal Complexes with Crown Ethers and Cryptands. Chemphyschem 2019; 20:2060-2062. [PMID: 31184431 DOI: 10.1002/cphc.201900422] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/10/2019] [Indexed: 11/10/2022]
Abstract
Electronic properties of series of alkali metals complexes with crown ethers and cryptands were studied via DFT hybrid functionals. For [M([2.2.2]crypt)] (M=Li, Na, K) extremely low (1.70-1.52 eV) adiabatic ionization potentials were found. Such low values of ionization energies are significantly lower than those of alkali metal atoms. Thus, the investigated complexes can be defined as superalkalis. As a result, our investigation opens up new directions in the designing of chemical species with record low ionization potentials and extends the explanation of the ability of the cryptates and alkali crown ether complexes to stabilize multiple charged Zintl ions.
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Affiliation(s)
- Nikolay V Tkachenko
- Department of Chemistry and Biochemistry, Utah State University Logan, Utah, 84322, United States
| | - Zhong-Ming Sun
- School of Materials Science and Engineering State Key Laboratory of Elemento-Organic Chemistry Tianjin Key Lab for Rare Earth Materials and Applications, Nankai University, Tianjin, 300350, China
| | - Alexander I Boldyrev
- Department of Chemistry and Biochemistry, Utah State University Logan, Utah, 84322, United States
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23
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Armstrong A, Reber AC, Khanna SN. Multiple-Valence Aluminum and the Electronic and Geometric Structure of Al nO m Clusters. J Phys Chem A 2019; 123:5114-5121. [PMID: 31146532 DOI: 10.1021/acs.jpca.9b01729] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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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24
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Sun WM, Wu D. Recent Progress on the Design, Characterization, and Application of Superalkalis. Chemistry 2019; 25:9568-9579. [PMID: 31025432 DOI: 10.1002/chem.201901460] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Indexed: 11/10/2022]
Abstract
Superalkalis are clusters or molecules featuring lower ionization energies (IEs) than that of cesium atoms, and thus exhibit excellent reducing properties. Such special species have great potential to be used in the synthesis of unusual charge-transfer salts and cluster-assembled nanomaterials with tailored properties, in the reduction of carbon dioxide, or as hydrogen storage materials and noble-gas-trapping agents, etc. In this regard, ongoing efforts have been devoted to designing and characterizing superalkalis of new types. The recent progress on the study of superalkalis in terms of theoretical design, characterization, and potential application is summarized in this minireview. We hope this review will not only provide a broad overview of this research field, but also highlight the prospect of further extending the experimental synthesis and practical application of superalkalis.
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Affiliation(s)
- Wei-Ming Sun
- Department of Basic Chemistry, School of Pharmacy, Fujian Medical University, Fuzhou, 350108, P. R. China
| | - Di Wu
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, 130023, P. R. China
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25
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Sun W, Zhang X, Pan K, Chen J, Wu D, Li C, Li Y, Li Z. On the Possibility of Using the Jellium Model as a Guide To Design Bimetallic Superalkali Cations. Chemistry 2019; 25:4358-4366. [DOI: 10.1002/chem.201806194] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Wei‐Ming Sun
- The School of PharmacyFujian Medical University Fuzhou 350108 P.R. China
| | - Xiao‐Ling Zhang
- The School of PharmacyFujian Medical University Fuzhou 350108 P.R. China
| | - Kai‐Yun Pan
- The School of PharmacyFujian Medical University Fuzhou 350108 P.R. China
| | - Jing‐Hua Chen
- The School of PharmacyFujian Medical University Fuzhou 350108 P.R. China
| | - Di Wu
- Laboratory of Theoretical and Computational ChemistryInstitute of Theoretical ChemistryJilin University Changchun 130023 P.R. China
| | - Chun‐Yan Li
- The School of PharmacyFujian Medical University Fuzhou 350108 P.R. China
| | - Ying Li
- Laboratory of Theoretical and Computational ChemistryInstitute of Theoretical ChemistryJilin University Changchun 130023 P.R. China
| | - Zhi‐Ru Li
- Laboratory of Theoretical and Computational ChemistryInstitute of Theoretical ChemistryJilin University Changchun 130023 P.R. China
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26
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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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