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Theiler PM, Ritz C, Hofmann R, Stemmer A. Detection of a Chirality-Induced Spin Selective Quantum Capacitance in α-Helical Peptides. NANO LETTERS 2023; 23:8280-8287. [PMID: 37650519 PMCID: PMC10510583 DOI: 10.1021/acs.nanolett.3c02483] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/24/2023] [Indexed: 09/01/2023]
Abstract
Advanced Kelvin probe force microscopy simultaneously detects the quantum capacitance and surface potential of an α-helical peptide monolayer. These indicators shift when either the magnetic polarization or the enantiomer is toggled. A model based on a triangular quantum well in thermal and chemical equilibrium and electron-electron interactions allows for calculating the electrical potential profile from the measured data. The combination of the model and the measurements shows that no global charge transport is required to produce effects attributed to the chirality-induced spin selectivity effect. These experimental findings support the theoretical model of Fransson et al. Nano Letters 2021, 21 (7), 3026-3032. Measurements of the quantum capacitance represent a new way to test and refine theoretical models used to explain strong spin polarization due to chirality-induced spin selectivity.
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Affiliation(s)
- Pius Markus Theiler
- Nanotechnology
Group, ETH Zürich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Christian Ritz
- Nanotechnology
Group, ETH Zürich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Raphael Hofmann
- Laboratory
of Organic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland
| | - Andreas Stemmer
- Nanotechnology
Group, ETH Zürich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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2
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Nguyen TNH, Rasabathina L, Hellwig O, Sharma A, Salvan G, Yochelis S, Paltiel Y, Baczewski LT, Tegenkamp C. Cooperative Effect of Electron Spin Polarization in Chiral Molecules Studied with Non-Spin-Polarized Scanning Tunneling Microscopy. ACS APPLIED MATERIALS & INTERFACES 2022; 14:38013-38020. [PMID: 35960822 DOI: 10.1021/acsami.2c08668] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Polyalanine molecules (PA) with an α-helix conformation have recently attracted a great deal of interest, as the propagation of electrons through the chiral backbone structure comes along with spin polarization of the transmitted electrons. By means of scanning tunneling microscopy and spectroscopy under ambient conditions, PA molecules adsorbed on surfaces of epitaxial magnetic Al2O3/Pt/Au/Co/Au nanostructures with perpendicular anisotropy were studied. Thereby, a correlation between the PA molecules ordering at the surface with the electron tunneling across this hybrid system as a function of the substrate magnetization orientation as well as the coverage density and helicity of the PA molecules was observed. The highest spin polarization values, P, were found for well-ordered self-assembled monolayers and with a defined chemical coupling of the molecules to the magnetic substrate surface, showing that the current-induced spin selectivity is a cooperative effect. Thereby, P deduced from the electron transmission along unoccupied molecular orbitals of the chiral molecules is larger as compared to values derived from the occupied molecular orbitals. Apparently, the larger orbital overlap results in a higher electron mobility, yielding a higher P value. By switching the magnetization direction of the Co layer, it was demonstrated that the non-spin-polarized STM can be used to study chiral molecules with a submolecular resolution, to detect properties of buried magnetic layers and to detect the spin polarization of the molecules from the change in the magnetoresistance of such hybrid structures.
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Affiliation(s)
- Thi Ngoc Ha Nguyen
- Solid Surface Analysis, Institute of Physics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany
| | - Lokesh Rasabathina
- Functional Magnetic Materials, Institute of Physics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany
| | - Olav Hellwig
- Functional Magnetic Materials, Institute of Physics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Apoorva Sharma
- Semiconductor Physics, Institute of Physics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany
| | - Georgeta Salvan
- Semiconductor Physics, Institute of Physics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany
| | - Shira Yochelis
- Department of Applied Physics, Hebrew University of Jerusalem, 91905 Jerusalem, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, 91905 Jerusalem, Israel
| | - Yossi Paltiel
- Department of Applied Physics, Hebrew University of Jerusalem, 91905 Jerusalem, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, 91905 Jerusalem, Israel
| | - Lech T Baczewski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warszawa, Poland
| | - Christoph Tegenkamp
- Solid Surface Analysis, Institute of Physics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany
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Song X, Bu Y. Electric field controlled uphill electron migration along α-helical oligopeptides. Phys Chem Chem Phys 2021; 23:1464-1474. [PMID: 33399139 DOI: 10.1039/d0cp05085g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A systematic study on applied electric field effects (Eapp) on electron transfer along the peptides is very important for the regulation of electron transfer behaviors so as to realize the functions of proteins. In this work, we computationally investigated the uphill migration behaviors of excess electrons along the peptide chains under Eapp using the density functional theory method. We examined the electronic property changes of the model α-helical oligopeptides, the dynamics behavior of an excess electron along the peptide chains under Eapp opposite to the internal dipole field of peptides. We found that Eapp of different intensities can effectively modulate the electron-binding abilities, Frontier molecular orbital (FMO) energies and distributions, dipole moments and other corresponding properties with different degrees. The electron-binding abilities of α-helical oligopeptides revealed by vertical electron affinity and FMO energies decrease in weak Eapp and then increase greatly in high Eapp, while the dipole moments change mildly in weak Eapp and increase significantly until a threshold and then become gentle in high Eapp. Analysis of FMO and electron distributions indicates that an excess electron can migrate uphill from the N-terminus to the C-terminus of the α-helical peptides in an irregular jump mode as Eapp linearly increases. Another interesting finding is that α-helical peptides with diverse chain lengths have different sensitivities to Eapp. The longer the peptide is, the more obvious the effects of Eapp are. Additionally, compared to the Eapp effect on linear oligopeptides, we summarized the systematic rule about the Eapp effect on excess electron migration uphill along the peptide chains. Clearly, this work not only enriches the information of the Eapp effect on electronic properties and electron transfers in the helical peptides, but also provides a new perspective for modulating electron migration behaviors in protein electronics engineering.
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Affiliation(s)
- Xiufang Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China.
| | - Yuxiang Bu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China.
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Song X, Fu Q, Bu Y. Nonlinear Migration Dynamics of Excess Electrons along Linear Oligopeptides Controlled by an Applied Electric Field. Chemphyschem 2019; 20:1497-1507. [PMID: 30912277 DOI: 10.1002/cphc.201900149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/16/2019] [Indexed: 11/06/2022]
Abstract
Migration of an excess electron along linear oligopeptides governed by the external electric field (Eex ) which is against the inner dipole electric field is theoretically investigated, including the effects of Eex on the structural and electronic properties of electron migration. Two structural properties including electron-binding ability and the dipole moment of linear oligopeptides are sensitive to the Eex values and can be largely modulated by Eex due to the competition of Eex and the inner electric field and electron transfer caused by Eex . In the case of low Eex values, two structural properties decrease slightly, while for high Eex values, the electron-binding ability continually increases strongly, with dipole moments firstly increasing significantly and then increasing more slowly at higher Eex . Additionally, linear oligopeptides of different chain lengths influence the modulation extent of Eex and the longer the chain length is, the more sensitive modulation of Eex is. In addition, electronic properties represented by electron spin densities and singly occupied molecular orbital distributions vary with Eex intensities, leading to an unusual electron migration behavior. As Eex increases, an excess electron transfers from the N-terminus to the C-terminus and jumps over a neighboring dipole unit of two termini to other units, respectively, instead of transferring by means of a one-by-one dipole unit hopping mechanism. These findings not only promote a deeper understanding of the connection between Eex and structural and electronic properties of electron transfer behavior in peptides, but also provide a new insight into the modulation of electron migration along the oligopeptides.
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Affiliation(s)
- Xiufang Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, People's Republic of China
| | - Qiang Fu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, People's Republic of China
| | - Yuxiang 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
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5
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Sigma-holes from iso-molecular electrostatic potential surfaces. J Mol Model 2019; 25:160. [PMID: 31089893 DOI: 10.1007/s00894-019-4051-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/24/2019] [Indexed: 01/04/2023]
Abstract
Visualization of the halobenzene σ-hole region of molecules (PhX, X = Cl, Br, I) was conducted to investigate the nature of the σ-hole present between covalently bonded elements of groups IVB-VIIB (known as halogen bonding for group VIIB) and corresponding negative sites, such as Lewis base lone electron pairs, π-electrons, or anions. The σ-hole consists of a region of poor electron density and often relatively positive electrostatic potential surrounding the outermost portion of the halogen atom along the A-X bond axis. In this work, molecular electrostatic potential (MEP) isosurfaces for PhX obtained from ab initio calculations are examined to determine the σ-hole in 3D, showing the surfaces of corresponding positive and negative regions. Surfaces were mapped for isopotentials of PhX molecules as low as 0.003 V and scaled up by factors of 10 up to 3 V. The σ-hole is revealed as a positive region exposed underneath a predominantly negative MEP isosurface. As isopotential values move away from zero, this hole grows in radius; conversely, its presence completely fades as potential approaches zero with increasing distance from the molecule. This technique can also be used to compare behaviors of neutral molecules and their ionic counterparts like the case of neutral PF6 (not observed experimentally) and the hexafluorophosphate anion, PF6-, a typical counter-ion in commercial Li-ion batteries. The pnictogen halide PF5 features similar MEP trends as the neutral PF6, which features reactive sites, shown as negative potential caps, at specific points in the molecule, similar to those of PF5. The portrayal of MEP behavior in iso-surfaces at specific and practical values of chemical interest is crucial when defining lump parameter sets for Coulombic force fields for molecular dynamics simulations to be used in systems that go from biological macromolecules to crystal engineering to devices to final products. Active chemical sites can be described by the MEP function, V(r), more proficiently than just wavefunctions or electron densities that intrinsically contain the same information, and this is fully enhanced when color-coding electron densities on isopotential surfaces are shown. Graphical abstract The hidden features of orbital holes depicted by iso-potentials.
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Sigma-Holes in Battery Materials Using Iso-Electrostatic Potential Surfaces. CRYSTALS 2018. [DOI: 10.3390/cryst8010033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Su G, Zhang M, Si W, Li ZT, Hou JL. Directional Potassium Transport through a Unimolecular Peptide Channel. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608428] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ge Su
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 China
| | - Min Zhang
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 China
| | - Wen Si
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 China
| | - Zhan-Ting Li
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 China
| | - Jun-Li Hou
- Department of Chemistry; Fudan University; 220 Handan Road Shanghai 200433 China
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Su G, Zhang M, Si W, Li Z, Hou J. Directional Potassium Transport through a Unimolecular Peptide Channel. Angew Chem Int Ed Engl 2016; 55:14678-14682. [DOI: 10.1002/anie.201608428] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Ge Su
- Department of Chemistry Fudan University 220 Handan Road Shanghai 200433 China
| | - Min Zhang
- Department of Chemistry Fudan University 220 Handan Road Shanghai 200433 China
| | - Wen Si
- Department of Chemistry Fudan University 220 Handan Road Shanghai 200433 China
| | - Zhan‐Ting Li
- Department of Chemistry Fudan University 220 Handan Road Shanghai 200433 China
| | - Jun‐Li Hou
- Department of Chemistry Fudan University 220 Handan Road Shanghai 200433 China
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Juhaniewicz J, Pawlowski J, Sek S. Electron Transport Mediated by Peptides Immobilized on Surfaces. Isr J Chem 2015. [DOI: 10.1002/ijch.201400165] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Benitez L, Cristancho D, Seminario J, Martinez de la Hoz J, Balbuena P. Electron transfer through solid-electrolyte-interphase layers formed on Si anodes of Li-ion batteries. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.05.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Alparone A. Evolution of Electric Dipole (Hyper)polarizabilities of β-Strand Polyglycine Single Chains: An ab Initio and DFT Theoretical Study. J Phys Chem A 2013; 117:5184-94. [DOI: 10.1021/jp403155q] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Andrea Alparone
- Department of Chemistry, University of Catania, viale A. Doria 6, Catania -95125, Italy
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12
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13
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Uji H, Morita T, Kimura S. Molecular direction dependence of single-molecule conductance of a helical peptide in molecular junction. Phys Chem Chem Phys 2013. [DOI: 10.1039/c2cp43499g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Alparone A. The effect of secondary structures on the NLO properties of single chain oligopeptides: a comparison between β-strand and α-helix polyglycines. Phys Chem Chem Phys 2013; 15:12958-62. [DOI: 10.1039/c3cp51496j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Ionization energy and electron affinity of oligoglycines: a CAM-B3LYP density functional theory study. MONATSHEFTE FUR CHEMIE 2012. [DOI: 10.1007/s00706-011-0700-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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16
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Kubli-Garfias C, Salazar-Salinas K, Perez-Angel EC, Seminario JM. Light activation of the isomerization and deprotonation of the protonated Schiff base retinal. J Mol Model 2011; 17:2539-47. [PMID: 21207087 DOI: 10.1007/s00894-010-0927-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 11/29/2010] [Indexed: 11/29/2022]
Abstract
We perform an ab initio analysis of the photoisomerization of the protonated Schiff base of retinal (PSB-retinal) from 11-cis to 11-trans rotating the C10-C11=C12-C13 dihedral angle from 0° (cis) to -180° (trans). We find that the retinal molecule shows the lowest rotational barrier (0.22 eV) when its charge state is zero as compared to the barrier for the protonated molecule which is ∼0.89 eV. We conclude that rotation most likely takes place in the excited state of the deprotonated retinal. The addition of a proton creates a much larger barrier implying a switching behavior of retinal that might be useful for several applications in molecular electronics. All conformations of the retinal compound absorb in the green region with small shifts following the dihedral angle rotation; however, the Schiff base of retinal (SB-retinal) at trans-conformation absorbs in the violet region. The rotation of the dihedral angle around the C11=C12 π-bond affects the absorption energy of the retinal and the binding energy of the SB-retinal with the proton at the N-Schiff; the binding energy is slightly lower at the trans-SB-retinal than at other conformations of the retinal.
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Affiliation(s)
- Carlos Kubli-Garfias
- Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
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