1
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Samal PP, Maiti A, Patel S, Paul H, Chandra G, Mishra P, Daschakraborty S, Nayak A. Quantifying Hydrogen-Bonding Interactions in the Self-Assembly of Photoresponsive Azobenzene Amphiphiles at the Air-Water Interface. J Phys Chem Lett 2024; 15:9193-9200. [PMID: 39213655 DOI: 10.1021/acs.jpclett.4c01897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Amphiphilic azobenzene molecules offer ample scope to design functional supramolecular systems in an aqueous medium that can be controlled by light. Despite their widespread applications in photopharmacology and optoelectronics, the self-assembly pathways and energy landscapes of these systems are not well understood. Here, we report combined molecular dynamics (MD) simulation and surface manometry studies on a specially designed alkylated, meta-substituted azobenzene derivative to quantify the hydrogen-bonding interactions in the self-assembled monolayers of its photoisomers. The z-density profile, radial distribution function, order parameters, and hydrogen bond analyzed using MD simulations corroborated the experimental observations of changes in surface pressure, dipole moment, and thickness of the monolayers. Even a small change in the number of hydrogen bonds in the molecule-molecule and molecule-water interactions causes significant changes in the monolayer properties. These results are fundamentally important for engineering photoresponsive molecules with tailored properties for applications in targeted drug delivery and other industrial applications.
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Affiliation(s)
| | - Archita Maiti
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, India 801103
| | - Samridhi Patel
- Department of Chemistry, Central University of South Bihar, Gaya, India 824236
| | - Himangshu Paul
- Department of Physics, Indian Institute of Technology Patna, Bihta, India 801103
| | - Girish Chandra
- Department of Chemistry, Central University of South Bihar, Gaya, India 824236
| | - Puneet Mishra
- Department of Physics, Central University of South Bihar, Gaya, India 824236
| | | | - Alpana Nayak
- Department of Physics, Indian Institute of Technology Patna, Bihta, India 801103
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2
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Kojima T, Xie C, Sakaguchi H. On-Surface Fabrication toward Polar 2D Macromolecular Crystals. Chempluschem 2024; 89:e202300775. [PMID: 38439510 DOI: 10.1002/cplu.202300775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 02/16/2024] [Accepted: 03/04/2024] [Indexed: 03/06/2024]
Abstract
Polar 2D macromolecular structures have attracted significant attention because of their ferroelectricity and ferro-magnetism. However, it is challenging to synthesize them experimentally because dipoles or spins of these macromolecules tend to cancel each other. So far, there has been no successful strategy for assembling macromolecules in a unidirectional manner, achieving stereoregular polymerization on metal surfaces, and creating polar 2D polymer crystals. Recent progress in molecular assembly, on-surface polymer synthesis, and direct control of molecules using electric field applications provides an opportunity to develop such strategies. In this regard, we first review past studies on chiral and achiral molecular assembly, on-surface polymer synthesis, and orientation control of polar molecules. Then, we discuss our newly developed approach called "vectorial on-surface synthesis", which is based on "dynamic chirality" of compass precursors, stereoselective polymerization, and favorable interchain interactions originating from CH-π interactions. Finally, we conclude with a prospective outlook.
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Affiliation(s)
- Takahiro Kojima
- Institute of Advanced Energy, Kyoto University, Gokasyo, Uji, Kyoto, 611-0011, Japan
| | - Cong Xie
- Institute of Advanced Energy, Kyoto University, Gokasyo, Uji, Kyoto, 611-0011, Japan
| | - Hiroshi Sakaguchi
- Institute of Advanced Energy, Kyoto University, Gokasyo, Uji, Kyoto, 611-0011, Japan
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3
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Brown T, Blowey PJ, Sweetman A. Precise determination of molecular adsorption geometries by room temperature non-contact atomic force microscopy. Commun Chem 2024; 7:8. [PMID: 38184736 PMCID: PMC10771516 DOI: 10.1038/s42004-023-01093-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 12/20/2023] [Indexed: 01/08/2024] Open
Abstract
High resolution force measurements of molecules on surfaces, in non-contact atomic force microscopy, are often only performed at cryogenic temperatures, due to needing a highly stable system, and a passivated probe tip (typically via CO-functionalisation). Here we show a reliable protocol for acquiring three-dimensional force map data over both single organic molecules and assembled islands of molecules, at room temperature. Isolated cobalt phthalocyanine and islands of C60 are characterised with submolecular resolution, on a passivated silicon substrate (B:Si(111)-[Formula: see text]). Geometries of cobalt phthalocyanine are determined to a ~ 10 pm accuracy. For the C60, the protocol is sufficiently robust that areas spanning 10 nm × 10 nm are mapped, despite the difficulties of room temperature operation. These results provide a proof-of-concept for gathering high-resolution three-dimensional force maps of networks of complex, non-planar molecules on surfaces, in conditions more analogous to real-world application.
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4
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Zhang N, Li J, Kou J, Sun C. Effects of Hydrogen Bonds between Ethoxylated Alcohols and Sodium Oleate on Collecting Performance in Flotation of Quartz. Molecules 2023; 28:6945. [PMID: 37836788 PMCID: PMC10574789 DOI: 10.3390/molecules28196945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Hydrogen bonds play an important role in the interaction between surfactants. In this study, the effect of three different ethoxylated alcohols (OP-10, NP-10, AEO-9) on the collecting behavior of sodium oleate (NaOL) in the flotation of quartz was investigated. To explore the mechanism, the hydrogen bond between ethoxylated alcohols and NaOL was analyzed using molecular dynamics (MD) simulation. The results showed that ethoxylated alcohols promoted the collecting performance of NaOL and reduced the dosage of the activator CaO and the collector NaOL in the flotation of quartz. The Zeta potential measurement illustrated that ethoxylated alcohols promoted the adsorption of OL- on the activated quartz surface and the degree of promotion was in the order of OP-10 > NP-10 > AEO-9. The MD simulation results showed that a hydrogen bond presented between ethoxylated alcohols and OL-. Due to the hydrogen bond between the ethoxylated alcohols and OL-, the attraction force between OL- and the quartz surface increased with the addition of ethoxylated alcohols in the order of OP-10 > NP-10 > AEO-9 based on the MD simulation results. As the result, the addition of ethoxylated alcohols increased the adsorption density of OL- on the activated quartz surface, which explained the promotion of the collecting performance of OL- in the flotation of quartz.
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Affiliation(s)
| | | | | | - Chunbao Sun
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China; (N.Z.)
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5
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Néel N, Kröger J. Orbital and Skeletal Structure of a Single Molecule on a Metal Surface Unveiled by Scanning Tunneling Microscopy. J Phys Chem Lett 2023; 14:3946-3952. [PMID: 37078645 DOI: 10.1021/acs.jpclett.3c00460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Atomic-scale spatial characteristics of a phthalocyanine orbital and skeleton are obtained on a metal surface with a scanning tunneling microscope and a CO-functionalized tip. Intriguingly, the high spatial resolution of the intramolecular electronic patterns is achieved without resonant tunneling into the orbital and despite the hybridization of the molecule with the reactive Cu substrate. The resolution can be fine-tuned by the tip-molecule distance, which controls the p-wave and s-wave contribution of the molecular probe to the imaging process. The detailed structure is deployed to minutely track the translation of the molecule in a reversible interconversion of rotational variants and to quantify relaxations of the adsorption geometry. Entering into the Pauli repulsion imaging mode, the intramolecular contrast loses its orbital character and reflects the molecular skeleton instead. The assignment of pyrrolic-hydrogen sites becomes possible, which in the orbital patterns remains elusive.
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Affiliation(s)
- Nicolas Néel
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - Jörg Kröger
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
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6
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Brown T, Blowey PJ, Henry J, Sweetman A. Intramolecular Force Mapping at Room Temperature. ACS NANO 2023; 17:1298-1304. [PMID: 36603104 PMCID: PMC9878970 DOI: 10.1021/acsnano.2c09463] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Acquisition of dense, three-dimensional, force fields with intramolecular resolution via noncontact atomic force microscopy (NC-AFM) has yielded enormous progress in our ability to characterize molecular and two-dimensional materials at the atomic scale. To date, intramolecular force mapping has been performed exclusively at cryogenic temperatures, due to the stability afforded by low temperature operation, and as the carbon monoxide functionalization of the metallic scanning probe tip, normally required for submolecular resolution, is only stable at low temperature. In this paper we show that high-resolution, three-dimensional force mapping of a single organic molecule is possible even at room temperature. The physical limitations of room temperature operation are overcome using semiconducting materials to inhibit molecular diffusion and create robust tip apexes, while challenges due to thermal drift are overcome with atom tracking based feedforward correction. Three-dimensional force maps comparable in spatial and force resolution to those acquired at low temperature are demonstrated, permitting a quantitative analysis of the adsorption induced changes in the geometry of the molecule at the picometer level.
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Affiliation(s)
- Timothy Brown
- The School of Physics and Astronomy,
Bragg Centre for Materials Research, The
University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Philip James Blowey
- The School of Physics and Astronomy,
Bragg Centre for Materials Research, The
University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Jack Henry
- The School of Physics and Astronomy,
Bragg Centre for Materials Research, The
University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Adam Sweetman
- The School of Physics and Astronomy,
Bragg Centre for Materials Research, The
University of Leeds, Leeds LS2 9JT, United Kingdom
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7
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Weymouth AJ, Roche E, Giessibl FJ. From a free electron gas to confined states: A mixed island of PTCDA and copper phthalocyanine on Ag(111). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:1572-1577. [PMID: 36628110 PMCID: PMC9795859 DOI: 10.3762/bjnano.13.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
When perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) is deposited on the Ag(111) surface at submonolayer coverage, it forms islands under which the native Shockley state of the Ag(111) surface can no longer be found. Previous work has shown that this state shifts upwards to form a new interface state starting at 0.6 V above the Fermi level, having properties of a two-dimensional electron gas (2DEG). We investigated mixed islands of PTCDA and copper phthalocyanine (CuPc) to study the change in the electronic state with the addition of an electron donor. We no longer observe a 2DEG state and instead identify states at 0.46 and 0.79 V. While one state appears in dI/dV images as an array of one-dimensional quantum wells, our analysis shows that this state does not act as a free electron gas and that the features are instead localized above individual PTCDA molecules.
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Affiliation(s)
- Alfred J Weymouth
- Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Emily Roche
- Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Franz J Giessibl
- Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93053 Regensburg, Germany
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8
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Quinn S, Davies ES, Pearce N, Rosenberg C, Pfeiffer CR, Orton GRF, Champness NR. Donor-Acceptor Dyads and Triads Employing Core-Substituted Naphthalene Diimides: A Synthetic and Spectro (Electrochemical) Study. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248671. [PMID: 36557805 PMCID: PMC9783862 DOI: 10.3390/molecules27248671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022]
Abstract
Donor-acceptor dyads and triads comprising core-substituted naphthalene diimide (NDI) chromophores and either phenothiazine or phenoxazine donors are described. Synthesis combined with electrochemical and spectroelectrochemical investigations facilitates characterisation of the various redox states of these molecules, confirming the ability to combine arrays of electron donating and accepting moieties into single species that retain the redox properties of these individual moieties.
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Affiliation(s)
- Samuel Quinn
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - E. Stephen Davies
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Nicholas Pearce
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Callum Rosenberg
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Constance R. Pfeiffer
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Georgia R. F. Orton
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Neil R. Champness
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- Correspondence:
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9
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Rothe K, Néel N, Bocquet ML, Kröger J. Tracking the Interaction between a CO-Functionalized Probe and Two Ag-Phthalocyanine Conformers by Local Vertical Force Spectroscopy. J Phys Chem A 2022; 126:6890-6897. [PMID: 36154143 DOI: 10.1021/acs.jpca.2c04760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Intentionally terminating scanning probes with a single atom or molecule belongs to a rapidly growing field in the quantum chemistry and physics at surfaces. However, the detailed understanding of the coupling between the probe and adsorbate is in its infancy. Here, an atomic force microscopy probe functionalized with a single CO molecule is approached with picometer control to two conformational isomers of Ag-phthalocyanine adsorbed on Ag(111). The isomer with the central Ag atom pointing to CO exhibits a complex evolution of the distance-dependent interaction, while the conformer with Ag bonded to the metal surface gives rise to a Lennard-Jones behavior. By virtue of spatially resolved force spectroscopy and the comparison with results obtained from microscope probes terminated with a single Ag atom, the mutual coupling of the protruding O atom of the tip and the Ag atom of the phthalocyanine molecule is identified as the cause for the unconventional variation of the force. Simulations of the entire junction within density functional theory unveil the presence of ample relaxations in the case of one conformer, which represents a rationale for the peculiar vertical-distance evolution of the interaction. The simulations highlight the role of physisorption, chemisorption, and unexpected junction distortions at the verge of bond formation in the interpretation of the distance-dependent force between two molecules.
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Affiliation(s)
- Karl Rothe
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - Nicolas Néel
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - Marie-Laure Bocquet
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, F-75005 Paris, France
| | - Jörg Kröger
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
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10
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Rothe K, Néel N, Bocquet ML, Kröger J. Extraction of Chemical Reactivity and Structural Relaxations of an Organic Dye from the Short-Range Interaction with a Molecular Probe. J Phys Chem Lett 2022; 13:8660-8665. [PMID: 36084075 DOI: 10.1021/acs.jpclett.2c02140] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A CO-functionalized atomic force microscope tip is used to locally probe local chemical reactivity and subtle structural relaxations of a single phthalocyanine molecule at different stages of pyrrolic-H abstraction. Spatially resolved vertical force spectroscopy unveils a variation of the maximum short-range attraction between CO and intramolecular sites, which is interpreted as a measure for the local chemical reactivity. In addition, the vertical position of the point of maximum attraction is observed to vary across the molecules. These changes follow the calculated adsorption heights of the probed molecular atoms.
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Affiliation(s)
- Karl Rothe
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - Nicolas Néel
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - Marie-Laure Bocquet
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, F-75005 Paris, France
| | - Jörg Kröger
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
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11
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Wang D, Wang Z, Liu W, Zhong S, Feng YP, Loh KP, Wee ATS. Real-Space Investigation of the Multiple Halogen Bonds by Ultrahigh-Resolution Scanning Probe Microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202368. [PMID: 35719029 DOI: 10.1002/smll.202202368] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Indexed: 06/15/2023]
Abstract
The chemical bond is of central interest in chemistry, and it is of significance to study the nature of intermolecular bonds in real-space. Herein, non-contact atomic force microscopy (nc-AFM) and low-temperature scanning tunneling microscopy (LT-STM) are employed to acquire real-space atomic information of molecular clusters, i.e., monomer, dimer, trimer, tetramer, formed on Au(111). The formation of the various molecular clusters is due to the diversity of halogen bonds. DFT calculation also suggests the formation of three distinct halogen bonds among the molecular clusters, which originates from the noncovalent interactions of Br-atoms with the positive potential H-atoms, neutral potential Br-atoms, and negative potential N-atoms, respectively. This work demonstrates the real-space investigation of the multiple halogen bonds by nc-AFM/LT-STM, indicating the potential use of this technique to study other intermolecular bonds and to understand complex supramolecular assemblies at the atomic/sub-molecular level.
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Affiliation(s)
- Dingguan Wang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Zishen Wang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Wei Liu
- School of Physics, Southeast University, 2 Southeast University Road, Nanjing, China
| | - Siying Zhong
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Andrew Thye Shen Wee
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
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12
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Li D, Zhang L. Structure Prediction and Potential Inhibitors Docking of Enterovirus 2C Proteins. Front Microbiol 2022; 13:856574. [PMID: 35572704 PMCID: PMC9100428 DOI: 10.3389/fmicb.2022.856574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/31/2022] [Indexed: 11/18/2022] Open
Abstract
Human enterovirus infections are mostly asymptomatic and occasionally could be severe and life-threatening. The conserved non-structural 2C from enteroviruses protein is a promising target in antiviral therapies against human enteroviruses. Understanding of 2C-drug interactions is crucial for developing the potential antiviral agents. While functions of enterovirus 2C proteins have been widely studied, three-dimensional structure information of 2C is limited. In this study, the structures of 2C proteins from 20 enteroviruses were simulated and reconstructed using I-TASSER programs. Subsequent docking studies of the known 22 antiviral inhibitors for 2C proteins were performed to uncover the inhibitor-binding characteristics of 2C. Among the potential inhibitors, the compound hydantoin exhibited the highest broad-spectrum antiviral activities with binding to 2C protein. The anti-enteroviral activity of GuaHCL, compound 19b, R523062, compound 12a, compound 12b, quinoline analogs 12a, compound 19d, N6-benzyladenosine, dibucaine derivatives 6i, TBZE-029, fluoxetine analogs 2b, dibucaine, 2-(α-hydroxybenzyl)-benzimidazole (HBB), metrifudil, pirlindole, MRL-1237, quinoline analogs 10a, zuclopenthixol, fluoxetine, fluoxetine HCl, and quinoline analogs 12c showed a trend of gradual decrease. In addition, the free energy with 22 compounds binding to EV 2C ranged from −0.35 to −88.18 kcal/mol. Our in silico studies will provide important information for the development of pan-enterovirus antiviral agents based on 2C.
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Affiliation(s)
- Daoqun Li
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China
- Department of Pathogen Biology, School of Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
- Medical Science and Technology Innovation Center, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Leiliang Zhang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China
- Department of Pathogen Biology, School of Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
- Medical Science and Technology Innovation Center, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
- *Correspondence: Leiliang Zhang
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13
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Krieger A, Zika A, Gröhn F. Functional Nano-Objects by Electrostatic Self-Assembly: Structure, Switching, and Photocatalysis. Front Chem 2022; 9:779360. [PMID: 35359487 PMCID: PMC8961288 DOI: 10.3389/fchem.2021.779360] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/30/2021] [Indexed: 11/14/2022] Open
Abstract
The design of functional nano-objects by electrostatic self-assembly in solution signifies an emerging field with great potential. More specifically, the targeted combination of electrostatic interaction with other effects and interactions, such as the positioning of charges on stiff building blocks, the use of additional amphiphilic, π-π stacking building blocks, or polyelectrolytes with certain architectures, have recently promulgated electrostatic self-assembly to a principle for versatile defined structure formation. A large variety of architectures from spheres over rods and hollow spheres to networks in the size range of a few tenths to a few hundred nanometers can be formed. This review discusses the state-of-the-art of different approaches of nano-object formation by electrostatic self-assembly against the backdrop of corresponding solid materials and assemblies formed by other non-covalent interactions. In this regard, particularly promising is the facile formation of triggerable structures, i.e. size and shape switching through light, as well as the use of electrostatically assembled nano-objects for improved photocatalysis and the possible solar energy conversion in the future. Lately, this new field is eliciting an increasing amount of understanding; insights and limitations thereof are addressed in this article. Special emphasis is placed on the interconnection of molecular building block structures and the resulting nanoscale architecture via the key of thermodynamics.
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Affiliation(s)
| | | | - Franziska Gröhn
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM) and Bavarian Polymer Institute (BPI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
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14
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Abbasi-Pérez D, Sang H, Junqueira FLQ, Sweetman A, Recio JM, Moriarty P, Kantorovich L. Cyclic Single Atom Vertical Manipulation on a Nonmetallic Surface. J Phys Chem Lett 2021; 12:11383-11390. [PMID: 34784484 DOI: 10.1021/acs.jpclett.1c02271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Motivated by the quest for experimental procedures capable of controlled manipulation of single atoms on surfaces, we set up a computational strategy that explores the cyclical vertical manipulation of a broad set of single atoms on the GaAs(110) surface. First-principles simulations of atomic force microscope tip-sample interactions were performed considering families of GaAs and Au-terminated tip apexes with varying crystalline termination. We identified a subset of tips capable of both picking up and depositing an adatom (Ga, As, Al, and Au) any number of times via a modify-restore cycle that "resets" the apex of the scanning probe to its original structure at the end of each cycle. Manipulation becomes successful within a certain window of lateral and vertical tip distances that are observed to be different for extracting and depositing each atom. A practical experimental protocol of special utility for potential cyclical manipulation of single atoms on a nonmetallic surface is proposed.
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Affiliation(s)
| | - Hongqian Sang
- Department of Physics, King's College London, London WC2R 2LS, U.K
- Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China
| | - Filipe L Q Junqueira
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, U.K
| | - Adam Sweetman
- School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - J Manuel Recio
- MALTA-Consolider Team and Department of Analytical and Physical Chemistry, Universidad de Oviedo, Oviedo 33006, Spain
| | - Philip Moriarty
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, U.K
| | - Lev Kantorovich
- Department of Physics, King's College London, London WC2R 2LS, U.K
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15
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Zahl P, Yakutovich AV, Ventura-Macías E, Carracedo-Cosme J, Romero-Muñiz C, Pou P, Sadowski JT, Hybertsen MS, Pérez R. Hydrogen bonded trimesic acid networks on Cu(111) reveal how basic chemical properties are imprinted in HR-AFM images. NANOSCALE 2021; 13:18473-18482. [PMID: 34580697 DOI: 10.1039/d1nr04471k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
High resolution non-contact atomic force microscopy measurements characterize assemblies of trimesic acid molecules on Cu(111) and the link group interactions, providing the first fingerprints utilizing CO-based probes for this widely studied paradigm for hydrogen bond driven molecular self assembly. The enhanced submolecular resolution offered by this technique uniquely reveals key aspects of the competing interactions. Accurate comparison between full-density-based modeled images and experiment allows to identify key structural elements in the assembly in terms of the electron-withdrawing character of the carboxylic groups, interactions of those groups with Cu atoms in the surface, and the valence electron density in the intermolecular region of the hydrogen bonds. This study of trimesic acid assemblies on Cu(111) combining high resolution atomic force microscopy measurements with theory and simulation forges clear connections between fundamental chemical properties of molecules and key features imprinted in force images with submolecular resolution.
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Affiliation(s)
- Percy Zahl
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
| | - Aliaksandr V Yakutovich
- Swiss Federal Laboratories for Materials Science and Technology (Empa), nanotech@surfaces laboratory, CH-8600 Dübendorf, Switzerland
| | - Emiliano Ventura-Macías
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Jaime Carracedo-Cosme
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Quasar Science Resources S.L., Camino de las Ceudas 2, E-28232 Las Rozas, Madrid, Spain
| | - Carlos Romero-Muñiz
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, E-41013, Seville, Spain
| | - Pablo Pou
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
| | - Jerzy T Sadowski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
| | - Mark S Hybertsen
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
| | - Rubén Pérez
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
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16
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Schulze Lammers B, Yesilpinar D, Timmer A, Hu Z, Ji W, Amirjalayer S, Fuchs H, Mönig H. Benchmarking atomically defined AFM tips for chemical-selective imaging. NANOSCALE 2021; 13:13617-13623. [PMID: 34477636 DOI: 10.1039/d1nr04080d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Controlling the identity of the tip-terminating atom or molecule in low-temperature atomic force microscopy has led to ground breaking progress in surface chemistry and nanotechnology. Lacking a comparative tip-performance assessment, a profound standardization in such experiments is highly desirable. Here we directly compare the imaging and force-spectroscopy capabilities of four atomically defined tips, namely Cu-, Xe-, CO-, and O-terminated Cu-tips (CuOx-tips). Using a nanostructured copper-oxide surface as benchmark system, we found that Cu-tips react with surface oxygen, while chemically inert Xe- and CO-tips allow entering the repulsive force regime enabling increased resolution. However, their high flexibility leads to imaging artifacts and their strong passivation suppresses the chemical contrast. The higher rigidity and selectively increased chemical reactivity of CuOx-tips prevent tip-bending artifacts and generate a distinct chemical contrast. This result is particularly promising in view of future studies on other metal-oxide surfaces.
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Affiliation(s)
- Bertram Schulze Lammers
- Physikalisches Institut, Westfälische Wilhelms-Universität, 48149 Münster, Germany.
- Center for Nanotechnology, 48149 Münster, Germany
| | - Damla Yesilpinar
- Physikalisches Institut, Westfälische Wilhelms-Universität, 48149 Münster, Germany.
- Center for Nanotechnology, 48149 Münster, Germany
| | | | - Zhixin Hu
- Center for Quantum Joint Studies and Department of Physics, Tianjin University, Tianjin, China.
| | - Wei Ji
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, China
| | - Saeed Amirjalayer
- Physikalisches Institut, Westfälische Wilhelms-Universität, 48149 Münster, Germany.
- Center for Nanotechnology, 48149 Münster, Germany
- Center for Multiscale Theory and Computation, 48149 Münster, Germany
| | - Harald Fuchs
- Physikalisches Institut, Westfälische Wilhelms-Universität, 48149 Münster, Germany.
- Center for Nanotechnology, 48149 Münster, Germany
| | - Harry Mönig
- Physikalisches Institut, Westfälische Wilhelms-Universität, 48149 Münster, Germany.
- Center for Nanotechnology, 48149 Münster, Germany
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17
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Dou Z, Qian J, Li Y, Lin R, Wang J, Cheng P, Xu Z. Reducing molecular simulation time for AFM images based on super-resolution methods. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:775-785. [PMID: 34386314 PMCID: PMC8329368 DOI: 10.3762/bjnano.12.61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Atomic force microscopy (AFM) has been an important tool for nanoscale imaging and characterization with atomic and subatomic resolution. Theoretical investigations are getting highly important for the interpretation of AFM images. Researchers have used molecular simulation to examine the AFM imaging mechanism. With a recent flurry of researches applying machine learning to AFM, AFM images obtained from molecular simulation have also been used as training data. However, the simulation is incredibly time consuming. In this paper, we apply super-resolution methods, including compressed sensing and deep learning methods, to reconstruct simulated images and to reduce simulation time. Several molecular simulation energy maps under different conditions are presented to demonstrate the performance of reconstruction algorithms. Through the analysis of reconstructed results, we find that both presented algorithms could complete the reconstruction with good quality and greatly reduce simulation time. Moreover, the super-resolution methods can be used to speed up the generation of training data and vary simulation resolution for AFM machine learning.
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Affiliation(s)
- Zhipeng Dou
- School of Physics, Beihang University, Beijing 100083, China
| | - Jianqiang Qian
- School of Physics, Beihang University, Beijing 100083, China
| | - Yingzi Li
- School of Physics, Beihang University, Beijing 100083, China
| | - Rui Lin
- School of Physics, Beihang University, Beijing 100083, China
| | - Jianhai Wang
- School of Physics, Beihang University, Beijing 100083, China
| | - Peng Cheng
- School of Physics, Beihang University, Beijing 100083, China
| | - Zeyu Xu
- School of Physics, Beihang University, Beijing 100083, China
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18
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Chen P, Fatayer S, Schuler B, Metz JN, Gross L, Yao N, Zhang Y. The Role of Methyl Groups in the Early Stage of Thermal Polymerization of Polycyclic Aromatic Hydrocarbons Revealed by Molecular Imaging. ENERGY & FUELS : AN AMERICAN CHEMICAL SOCIETY JOURNAL 2021; 35:2224-2233. [PMID: 33574639 PMCID: PMC7869141 DOI: 10.1021/acs.energyfuels.0c04016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/23/2020] [Indexed: 05/03/2023]
Abstract
The initial thermal reactions of aromatic hydrocarbons are relevant to many industrial applications. However, tracking the growing number of heavy polycyclic aromatic hydrocarbon (PAH) products is extremely challenging because many reactions are unfolding in parallel from a mixture of molecules. Herein, we studied the reactions of 2,7-dimethylpyrene (DMPY) to decipher the roles of methyl substituents during mild thermal treatment. We found that the presence of methyl substituents is key for reducing the thermal severity required to initiate chemical reactions in natural molecular mixtures. A complex mixture of thermal products including monomers, dimers, and trimers was characterized by NMR, mass spectrometry, and noncontact atomic force microscopy (nc-AFM). A wide range of structural transformations including methyl transfer and polymerization reactions were identified. A detailed mechanistic understanding on the roles of H radicals during the polymerization of polycyclic aromatic hydrocarbons was obtained.
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Affiliation(s)
- Pengcheng Chen
- Princeton
Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08540, United States
| | - Shadi Fatayer
- IBM
Research−Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Bruno Schuler
- Empa,
Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Jordan N. Metz
- Corporate
Strategic Research, ExxonMobil Research
and Engineering Company, 1545 Route 22 E., Annandale, New Jersey 08801, United States
| | - Leo Gross
- IBM
Research−Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Nan Yao
- Princeton
Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08540, United States
| | - Yunlong Zhang
- Corporate
Strategic Research, ExxonMobil Research
and Engineering Company, 1545 Route 22 E., Annandale, New Jersey 08801, United States
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19
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Schultz JF, Yang B, Jiang N. On-surface formation of metal–organic coordination networks with C⋯Ag⋯C and C=O⋯Ag interactions assisted by precursor self-assembly. J Chem Phys 2021; 154:044703. [DOI: 10.1063/5.0038559] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Jeremy F. Schultz
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Bing Yang
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Liaoning 116023, China
| | - Nan Jiang
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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20
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Single hydrogen atom manipulation for reversible deprotonation of water on a rutile TiO 2 (110) surface. Commun Chem 2021; 4:5. [PMID: 36697495 PMCID: PMC9814442 DOI: 10.1038/s42004-020-00444-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/07/2020] [Indexed: 01/28/2023] Open
Abstract
The discovery of hydrogen atoms on the TiO2 surface is crucial for many practical applications, including photocatalytic water splitting. Electronically activating interfacial hydrogen atoms on the TiO2 surface is a common way to control their reactivity. Modulating the potential landscape is another way, but dedicated studies for such an activation are limited. Here we show the single hydrogen atom manipulation, and on-surface facilitated water deprotonation process on a rutile TiO2 (110) surface using low temperature atomic force microscopy and Kelvin probe force spectroscopy. The configuration of the hydrogen atom is manipulated on this surface step by step using the local field. Furthermore, we quantify the force needed to relocate the hydrogen atom on this surface using force spectroscopy and density functional theory. Reliable control of hydrogen atoms provides a new mechanistic insight of the water molecules on a metal oxide surface.
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21
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Hydrogen-bonded host-guest systems are stable in ionic liquids. Sci Rep 2020; 10:15414. [PMID: 32963260 PMCID: PMC7508985 DOI: 10.1038/s41598-020-71803-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 07/17/2020] [Indexed: 11/08/2022] Open
Abstract
We show that H-bonded host–guest systems associate in ionic liquids (ILs), pure salts with melting point below room temperature, in which dipole–dipole electrostatic interactions should be negligible in comparison with dipole-charge interactions. Binding constants (Ka) obtained from titrations of four H-bonded host–guest systems in two organic solvents and two ionic liquids yield smaller yet comparable Ka values in ionic liquids than in organic solvents. We also detect the association event using force spectroscopy, which confirms that the binding is not solely due to (de)solvation processes. Our results indicate that classic H-bonded host–guest supramolecular chemistry takes place in ILs. This implies that strong H-bonds are only moderately affected by surroundings composed entirely of charges, which can be interpreted as an indication that the balance of Coulombic to covalent forces in strong H-bonds is not tipped towards the former.
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22
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Laflör L, Reichling M, Rahe P. Protruding hydrogen atoms as markers for the molecular orientation of a metallocene. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1432-1438. [PMID: 33029472 PMCID: PMC7522462 DOI: 10.3762/bjnano.11.127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
A distinct dumbbell shape is observed as the dominant contrast feature in the experimental data when imaging 1,1'-ferrocene dicarboxylic acid (FDCA) molecules on bulk and thin film CaF2(111) surfaces with non-contact atomic force microscopy (NC-AFM). We use NC-AFM image calculations with the probe particle model to interpret this distinct shape by repulsive interactions between the NC-AFM tip and the top hydrogen atoms of the cyclopentadienyl (Cp) rings. Simulated NC-AFM images show an excellent agreement with experimental constant-height NC-AFM data of FDCA molecules at several tip-sample distances. By measuring this distinct dumbbell shape together with the molecular orientation, a strategy is proposed to determine the conformation of the ferrocene moiety, herein on CaF2(111) surfaces, by using the protruding hydrogen atoms as markers.
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Affiliation(s)
- Linda Laflör
- Fachbereich Physik, Universität Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany
| | - Michael Reichling
- Fachbereich Physik, Universität Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany
| | - Philipp Rahe
- Fachbereich Physik, Universität Osnabrück, Barbarastrasse 7, 49076 Osnabrück, Germany
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23
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Lawrence J, Sosso GC, Đorđević L, Pinfold H, Bonifazi D, Costantini G. Combining high-resolution scanning tunnelling microscopy and first-principles simulations to identify halogen bonding. Nat Commun 2020; 11:2103. [PMID: 32355173 PMCID: PMC7192931 DOI: 10.1038/s41467-020-15898-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 03/24/2020] [Indexed: 12/02/2022] Open
Abstract
Scanning tunnelling microscopy (STM) is commonly used to identify on-surface molecular self-assembled structures. However, its limited ability to reveal only the overall shape of molecules and their relative positions is not always enough to fully solve a supramolecular structure. Here, we analyse the assembly of a brominated polycyclic aromatic molecule on Au(111) and demonstrate that standard STM measurements cannot conclusively establish the nature of the intermolecular interactions. By performing high-resolution STM with a CO-functionalised tip, we clearly identify the location of rings and halogen atoms, determining that halogen bonding governs the assemblies. This is supported by density functional theory calculations that predict a stronger interaction energy for halogen rather than hydrogen bonding and by an electron density topology analysis that identifies characteristic features of halogen bonding. A similar approach should be able to solve many complex 2D supramolecular structures, and we predict its increasing use in molecular nanoscience at surfaces.
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Affiliation(s)
- James Lawrence
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Gabriele C Sosso
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
- Centre for Scientific Computing, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Luka Đorđević
- School of Chemistry, Cardiff University, Park Place Main Building, Cardiff, CF10 3AT, UK
| | - Harry Pinfold
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Davide Bonifazi
- School of Chemistry, Cardiff University, Park Place Main Building, Cardiff, CF10 3AT, UK.
| | - Giovanni Costantini
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
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24
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Yesilpinar D, Schulze Lammers B, Timmer A, Amirjalayer S, Fuchs H, Mönig H. High resolution noncontact atomic force microscopy imaging with oxygen-terminated copper tips at 78 K. NANOSCALE 2020; 12:2961-2965. [PMID: 31970359 DOI: 10.1039/c9nr10450j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Functionalizing atomic force microscopy (AFM) tips by picking up single inert probe particles like CO or Xe from the surface drastically increase the resolution. In particular, this approach allows imaging organic molecules with submolecular resolution revealing their internal bonding structure. However, due to the weak coupling of these probe particles to both, the surface they are picked up from and the tip apex, these experiments require liquid helium temperatures (i.e.≈5 K). In the present study we demonstrate that functionalizing an AFM tip with an atomically defined O-terminated copper tip (CuOx tip) allows performing such experiments at liquid nitrogen temperatures (i.e.≈78 K) with outstanding quality. We show that it is possible to utilize CuOx tips for chemically selective imaging of a copper oxide nanodomain on a partially oxidized Cu(110) surface in the repulsive force regime at elevated temperatures. Moreover, the high structural and chemical stability of CuOx tips allow even ex situ investigations where these tips are used to perform experiments on other, non-Cu, non-oxidized, substrates. In particular, we present results obtained from a dicoronylene (DCLN) molecule with submolecular resolution. An analysis of inner and peripheral bond lengths of the DCLN molecule shows excellent agreement with theoretical gas phase simulations emphasizing the exceptional imaging properties of CuOx tips also at elevated temperatures.
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Affiliation(s)
- Damla Yesilpinar
- Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
| | - Bertram Schulze Lammers
- Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
| | - Alexander Timmer
- Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
| | - Saeed Amirjalayer
- Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
| | - Harald Fuchs
- Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
| | - Harry Mönig
- Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
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25
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Webber AL, Yates JR, Zilka M, Sturniolo S, Uldry AC, Corlett EK, Pickard CJ, Pérez-Torralba M, Angeles Garcia M, Santa Maria D, Claramunt RM, Brown SP. Weak Intermolecular CH···N Hydrogen Bonding: Determination of 13CH- 15N Hydrogen-Bond Mediated J Couplings by Solid-State NMR Spectroscopy and First-Principles Calculations. J Phys Chem A 2020; 124:560-572. [PMID: 31880451 DOI: 10.1021/acs.jpca.9b10726] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Weak hydrogen bonds are increasingly hypothesized to play key roles in a wide range of chemistry from catalysis to gelation to polymer structure. Here, 15N/13C spin-echo magic-angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) experiments are applied to "view" intermolecular CH···N hydrogen bonding in two selectively labeled organic compounds, 4-[15N] cyano-4'-[13C2] ethynylbiphenyl (1) and [15N3,13C6]-2,4,6-triethynyl-1,3,5-triazine (2). The synthesis of 2-15N3,13C6 is reported here for the first time via a multistep procedure, where the key element is the reaction of [15N3]-2,4,6-trichloro-1,3,5-triazine (5) with [13C2]-[(trimethylsilyl)ethynyl]zinc chloride (8) to afford its immediate precursor [15N3,13C6]-2,4,6-tris[(trimethylsilyl)ethynyl]-1,3,5-triazine (9). Experimentally determined hydrogen-bond-mediated 2hJCN couplings (4.7 ± 0.4 Hz (1) and 4.1 ± 0.3 Hz (2)) are compared with density functional theory (DFT) gauge-including projector augmented wave (GIPAW) calculations, whereby species-independent coupling values 2hKCN (29.0 × 1019 kg m-2 s-2 A-2 (1) and 27.9 × 1019 kg m-2 s-2 A-2 (2)) quantitatively demonstrate the J couplings for these "weak" CH···N hydrogen bonds to be of a similar magnitude to those for conventionally observed NH···O hydrogen-bonding interactions in uracil (2hKNO: 28.1 and 36.8 × 1019 kg m-2 s-2 A-2). Moreover, the GIPAW calculations show a clear correlation between increasing 2hJCN (and 3hJCN) coupling and reducing C(H)···N and H···N hydrogen-bonding distances, with the Fermi contact term accounting for at least 98% of the isotropic 2hJCN coupling.
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Affiliation(s)
- Amy L Webber
- Department of Physics , University of Warwick , Coventry CV4 7AL , U.K
| | - Jonathan R Yates
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , U.K
| | - Miri Zilka
- Department of Physics , University of Warwick , Coventry CV4 7AL , U.K
| | - Simone Sturniolo
- Scientific Computing Department , Rutherford Appleton Laboratory , Chilton, Didcot , Oxfordshire OX11 0QX , U.K
| | - Anne-Christine Uldry
- Department for Biomedical Research , University of Bern , Freiburgstrasse 15 , Bern 3010 , Switzerland
| | - Emily K Corlett
- Department of Physics , University of Warwick , Coventry CV4 7AL , U.K
| | - Chris J Pickard
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , U.K.,Advanced Institute for Materials Research , Tohoku University 2-1-1 Katahira , Aoba, Sendai 980-8577 , Japan
| | - Marta Pérez-Torralba
- Departamento de Química Orgánica y Bio-Orgánica , Facultad de Ciencias, UNED , Senda del Rey 9 , Madrid E-28040 , Spain
| | - M Angeles Garcia
- Departamento de Química Orgánica y Bio-Orgánica , Facultad de Ciencias, UNED , Senda del Rey 9 , Madrid E-28040 , Spain
| | - Dolores Santa Maria
- Departamento de Química Orgánica y Bio-Orgánica , Facultad de Ciencias, UNED , Senda del Rey 9 , Madrid E-28040 , Spain
| | - Rosa M Claramunt
- Departamento de Química Orgánica y Bio-Orgánica , Facultad de Ciencias, UNED , Senda del Rey 9 , Madrid E-28040 , Spain
| | - Steven P Brown
- Department of Physics , University of Warwick , Coventry CV4 7AL , U.K
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26
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Sweetman A, Champness NR, Saywell A. On-surface chemical reactions characterised by ultra-high resolution scanning probe microscopy. Chem Soc Rev 2020; 49:4189-4202. [DOI: 10.1039/d0cs00166j] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The impact of high resolution scanning probe microscopy on imaging individual molecules with intramolecular resolution is reviewed.
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Affiliation(s)
- Adam Sweetman
- School of Physics and Astronomy
- University of Leeds
- Leeds
- UK
| | | | - Alex Saywell
- School of Physics and Astronomy
- University of Nottingham
- Nottingham
- UK
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27
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Mason SE, Beton PH, Besley NA. AIRBED: A Simplified Density Functional Theory Model for Physisorption on Surfaces. J Chem Theory Comput 2019; 15:5628-5634. [PMID: 31465207 DOI: 10.1021/acs.jctc.9b00576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dispersion interactions are commonly included in density functional theory (DFT) calculations through the addition of an empirical correction. In this study, a modification is made to the damping function in DFT-D2 calculations to describe repulsion at small internuclear distances. The resulting Atomic Interactions Represented By Empirical Dispersion (AIRBED) approach is used to model the physisorption of molecules on surfaces such as graphene and hexagonal boron nitride, where the constituent atoms of the surface are no longer required to be included explicitly in the density functional theory calculation but are represented by a point charge to capture electrostatic effects. It is shown that this model can reproduce the structures predicted by full DFT-D2 calculations to a high degree of accuracy. The significant reduction in computational cost allows much larger systems to be studied, including molecular arrays on surfaces and sandwich complexes involving organic molecules between two surface layers.
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Affiliation(s)
- Stephen E Mason
- School of Physics & Astronomy , University of Nottingham , University Park , Nottingham NG7 2RD , United Kingdom
| | - Peter H Beton
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , United Kindom
| | - Nicholas A Besley
- School of Physics & Astronomy , University of Nottingham , University Park , Nottingham NG7 2RD , United Kingdom
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28
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Yang Z, Lotze C, Corso M, Baum S, Franke KJ, Pascual JI. Direct Imaging of the Induced-Fit Effect in Molecular Self-Assembly. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1804713. [PMID: 30748106 DOI: 10.1002/smll.201804713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Molecular recognition is a crucial driving force for molecular self-assembly. In many cases molecules arrange in the lowest energy configuration following a lock-and-key principle. When molecular flexibility comes into play, the induced-fit effect may govern the self-assembly. Here, the self-assembly of dicyanovinyl-hexathiophene (DCV6T) molecules, a prototype specie for highly efficient organic solar cells, on Au(111) by using low-temperature scanning tunneling microscopy and atomic force microscopy is investigated. DCV6T molecules assemble on the surface forming either islands or chains. In the islands the molecules are straight-the lowest energy configuration in gas phase-and expose the dicyano moieties to form hydrogen bonds with neighbor molecules. In contrast, the structure of DCV6T molecules in the chain assemblies deviates significantly from their gas-phase analogues. The seemingly energetically unfavorable bent geometry is enforced by hydrogen-bonding intermolecular interactions. Density functional theory calculations of molecular dimers quantitatively demonstrate that the deformation of individual molecules optimizes the intermolecular bonding structure. The intermolecular bonding energy thus drives the chain structure formation, which is an expression of the induced-fit effect.
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Affiliation(s)
- Zechao Yang
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Christian Lotze
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Martina Corso
- Centro de Física de Materiales (CSIC-UPV/EHU) and Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastian, Spain
| | - Sebastian Baum
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Katharina J Franke
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - José I Pascual
- CIC nanoGUNE and Ikerbaske, Basque Foundation for Science, Tolosa Hiribidea 76, 20018, Donostia San Sebastian, Spain
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29
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Feng G, Zhang WX, Dong L, Li W, Cai W, Wei W, Ji L, Lin Z, Lu P. Negative area compressibility of a hydrogen-bonded two-dimensional material. Chem Sci 2019; 10:1309-1315. [PMID: 30809345 PMCID: PMC6357854 DOI: 10.1039/c8sc03291b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 12/02/2018] [Indexed: 11/21/2022] Open
Abstract
Very few materials expand two-dimensionally under pressure, and this extremely rare phenomenon, namely negative area compressibility (NAC), is highly desirable for technological applications in pressure sensors and actuators. Hitherto, the few known NAC materials have dominantly been limited to 2D crystals bonded via coordination interactions while other 2D systems have not been explored yet. Here, we report the large NAC of a hydrogen-bonded 2D supramolecular coordination complex, Zn(CH3COO)2·2H2O, with a synergistic microscopic mechanism. Our findings reveal that such an unusual phenomenon, over a wide pressure range of 0.15-4.44 GPa without the occurrence of any phase transitions, arises from the complex cooperation of intra-layer coordination and hydrogen-bonding interactions, and inter-layer van der Waals forces. In addition, we propose that these NAC crystals could have important applications as pressure-converting materials in ultrasensitive pressure sensing devices.
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Affiliation(s)
- Guoqiang Feng
- School of Materials Science and Engineering , Nankai University , Tianjin 300350 , China .
- Department of Physics and Mechanical & Electrical Engineering , Hubei University of Education , Wuhan 430205 , China
- School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , China .
| | - Wei-Xiong Zhang
- School of Chemistry and Chemical Engineering , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Liyuan Dong
- School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , China .
| | - Wei Li
- School of Materials Science and Engineering , Nankai University , Tianjin 300350 , China .
- School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , China .
| | - Weizhao Cai
- Department of Physics and Astronomy , University of Utah , Salt Lake City , Utah 84112 , USA .
| | - Wenjuan Wei
- School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , China .
| | - Lijun Ji
- School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , China .
| | - Zheshuai Lin
- Center for Crystal R&D , Key Lab of Functional Crystals and Laser Technology of Chinese Academy of Sciences , Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Beijing 100190 , China .
| | - Peixiang Lu
- School of Physics , Huazhong University of Science and Technology , Wuhan 430074 , China .
- Laboratory for Optical Information Technology , Wuhan Institute of Technology , Wuhan 430205 , China
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30
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Chutora T, de la Torre B, Mutombo P, Hellerstedt J, Kopeček J, Jelínek P, Švec M. Nitrous oxide as an effective AFM tip functionalization: a comparative study. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:315-321. [PMID: 30800570 PMCID: PMC6369984 DOI: 10.3762/bjnano.10.30] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/07/2019] [Indexed: 05/14/2023]
Abstract
We investigate the possibility of functionalizing Au tips by N2O molecules deposited on a Au(111) surface and their further use for imaging with submolecular resolution. First, we characterize the adsorption of the N2O species on Au(111) by means of atomic force microscopy with CO-functionalized tips and density functional theory (DFT) simulations. Subsequently we devise a method of attaching a single N2O to a metal tip apex and benchmark its high-resolution imaging and spectroscopic capabilities using FePc molecules. Our results demonstrate the feasibility of high-resolution imaging. However, we find an inherent asymmetry of the N2O probe-particle adsorption on the tip apex, in contrast to a CO tip reference. These findings are consistent with DFT calculations of the N2O- and CO tip apexes.
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Affiliation(s)
- Taras Chutora
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Bruno de la Torre
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Pingo Mutombo
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Jack Hellerstedt
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Jaromír Kopeček
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Pavel Jelínek
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Martin Švec
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
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31
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Ellner M, Pou P, Pérez R. Molecular Identification, Bond Order Discrimination, and Apparent Intermolecular Features in Atomic Force Microscopy Studied with a Charge Density Based Method. ACS NANO 2019; 13:786-795. [PMID: 30605593 DOI: 10.1021/acsnano.8b08209] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We introduce an efficient method to simulate high-resolution atomic force microscopy (HR-AFM) images with CO probes. Our model explicitly takes into account the charge densities of the sample and the probe for the calculation of the short-range (SR) interaction and retains ab initio accuracy with only two parameters, that are essentially universal, independent of the number of chemical species and the complexity of the bonding topology. The application to molecular images shows a strong dependence on the stoichiometry and bonding configuration that precludes the chemical identification of individual atoms based on local force-distance curves. However, we have identified features in the 2D images and 3D force maps that reflect the highly anisotropic spatial decay of the molecular charge density and provide a way toward molecular identification. The model treats SR and electrostatics interactions on an equal footing and correctly pinpoints the Pauli repulsion as the underlying interaction responsible for the bond order discrimination in C60. Finally, we settle the controversy regarding the origin of the intermolecular features, discarding the effect of the charge redistribution associated with the H bonds, and linking them with the overlap of the wave functions of the atoms that constitute the bond. This overlap creates saddle regions in the potential energy landscape that are sensed by the probe.
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Affiliation(s)
- Michael Ellner
- Departamento de Física Teórica de la Materia Condensada , Universidad Autónoma de Madrid , E-28049 Madrid , Spain
| | - Pablo Pou
- Departamento de Física Teórica de la Materia Condensada , Universidad Autónoma de Madrid , E-28049 Madrid , Spain
- Condensed Matter Physics Center (IFIMAC) , Universidad Autónoma de Madrid , E-28049 Madrid , Spain
| | - Rubén Pérez
- Departamento de Física Teórica de la Materia Condensada , Universidad Autónoma de Madrid , E-28049 Madrid , Spain
- Condensed Matter Physics Center (IFIMAC) , Universidad Autónoma de Madrid , E-28049 Madrid , Spain
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32
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Franconetti A, de Gonzalo G. Recent Developments on Supported Hydrogen-bond Organocatalysts. ChemCatChem 2018. [DOI: 10.1002/cctc.201801459] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Antonio Franconetti
- Departamento de Química; Universitat Autonoma de Barcelona; Cerdanyola del Vallés 01893 Spain
| | - Gonzalo de Gonzalo
- Departamento de Química Orgánica; Universidad de Sevilla; c/ Profesor García González 2 41012 Sevilla Spain
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33
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Preparation of chitosan-supported urea materials and their application in some organocatalytic procedures. Carbohydr Polym 2018; 199:365-374. [DOI: 10.1016/j.carbpol.2018.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 07/03/2018] [Accepted: 07/03/2018] [Indexed: 01/20/2023]
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34
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Kawai S, Krejčí O, Foster AS, Pawlak R, Xu F, Peng L, Orita A, Meyer E. Diacetylene Linked Anthracene Oligomers Synthesized by One-Shot Homocoupling of Trimethylsilyl on Cu(111). ACS NANO 2018; 12:8791-8797. [PMID: 30086235 DOI: 10.1021/acsnano.8b05116] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
On-surface chemical reaction has become a very powerful technique to conjugate small precursor molecules and several reactions have been proposed with the aim to fabricate functional nanostructures on surfaces. Here we present an unforeseen adsorption mode of 9,10-bis((trimethylsilyl)ethynyl)anthracene on a Cu(111)surface and the resulting one-shot desilylative homocoupling of of the adsorbate by annealing at 400 K. With a combination of high-resolution atomic force microscopy and density functional theory calculations, we found that the triple bonds and silicon atoms of the monomer chemically interact with the copper surface. After the oligomerization, we discovered that the anthracene units are linked to each other via buta-1,3-diynediyl fragments while keeping the surface clean. Furthermore, the force measurement revealed the chemical nature at the center of anthracene unit.
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Affiliation(s)
- Shigeki Kawai
- International Center for Materials Nanoarchitectonics , National Institute for Materials Science , 1-1, Namiki , Tsukuba , Ibaraki 305-0044 , Japan
| | - Ondrěj Krejčí
- Department of Applied Physics , Aalto University School of Science , P.O. Box 11100, FI-00076 Aalto , Finland
| | - Adam S Foster
- Department of Applied Physics , Aalto University School of Science , P.O. Box 11100, FI-00076 Aalto , Finland
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
- Graduate School Materials Science in Mainz , Staudinger Weg 9 , 55128 Mainz , Germany
| | - Rémy Pawlak
- Department of Physics , University of Basel , Klingelbergstrasse 82 , CH-4056 Basel , Switzerland
| | - Feng Xu
- Department of Applied Chemistry and Biotechnology , Okayama University of Science , 1-1 Ridai-cho, Kita-ku , Okayama 700-0005 , Japan
| | - Lifen Peng
- Department of Applied Chemistry and Biotechnology , Okayama University of Science , 1-1 Ridai-cho, Kita-ku , Okayama 700-0005 , Japan
| | - Akihiro Orita
- Department of Applied Chemistry and Biotechnology , Okayama University of Science , 1-1 Ridai-cho, Kita-ku , Okayama 700-0005 , Japan
| | - Ernst Meyer
- Department of Physics , University of Basel , Klingelbergstrasse 82 , CH-4056 Basel , Switzerland
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35
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Mönig H. Copper-oxide tip functionalization for submolecular atomic force microscopy. Chem Commun (Camb) 2018; 54:9874-9888. [PMID: 30124700 DOI: 10.1039/c8cc05332d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Establishing submolecular imaging in real-space by non-contact atomic force microscopy (NC-AFM) has been a major breakthrough in the field of organic surface chemistry. The key for the drastically increased resolution in these experiments is to functionalize a metallic tip apex with an inert probe particle. However, due to their weak bonding at the metal apex, these probe particles show a pronounced dynamic lateral deflection in the measurements. This constitutes a major limitation of this approach as it involves image distortions, an overestimation of bond lengths, and even artificial bond-like contrast features where actually no bonds exist. In this contribution, recent progress by using an alternative approach by copper-oxide tip functionalization is reviewed. Copper-oxide tips (CuOx tips) consist of a bulk copper apex, terminated by a covalently connected single oxygen atom, which chemically passivates the tip. Such CuOx tips can be identified by contrast analysis at specific surface sites and allow for submolecular resolution. A comparative analysis of data recorded with flexible tips allows a detailed discussion of the contrast mechanisms and related artificial effects. It is concluded with an assessment of limitations, future challenges and opportunities in such experiments.
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Affiliation(s)
- Harry Mönig
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany.
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36
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Mönig H, Amirjalayer S, Timmer A, Hu Z, Liu L, Díaz Arado O, Cnudde M, Strassert CA, Ji W, Rohlfing M, Fuchs H. Quantitative assessment of intermolecular interactions by atomic force microscopy imaging using copper oxide tips. NATURE NANOTECHNOLOGY 2018; 13:371-375. [PMID: 29632397 DOI: 10.1038/s41565-018-0104-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 02/22/2018] [Indexed: 05/10/2023]
Abstract
Atomic force microscopy is an impressive tool with which to directly resolve the bonding structure of organic compounds1-5. The methodology usually involves chemical passivation of the probe-tip termination by attaching single molecules or atoms such as CO or Xe (refs 1,6-9). However, these probe particles are only weakly connected to the metallic apex, which results in considerable dynamic deflection. This probe particle deflection leads to pronounced image distortions, systematic overestimation of bond lengths, and in some cases even spurious bond-like contrast features, thus inhibiting reliable data interpretation8-12. Recently, an alternative approach to tip passivation has been used in which slightly indenting a tip into oxidized copper substrates and subsequent contrast analysis allows for the verification of an oxygen-terminated Cu tip13-15. Here we show that, due to the covalently bound configuration of the terminal oxygen atom, this copper oxide tip (CuOx tip) has a high structural stability, allowing not only a quantitative determination of individual bond lengths and access to bond order effects, but also reliable intermolecular bond characterization. In particular, by removing the previous limitations of flexible probe particles, we are able to provide conclusive experimental evidence for an unusual intermolecular N-Au-N three-centre bond. Furthermore, we demonstrate that CuOx tips allow the characterization of the strength and configuration of individual hydrogen bonds within a molecular assembly.
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Affiliation(s)
- Harry Mönig
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany.
- Center for Nanotechnology, Münster, Germany.
| | - Saeed Amirjalayer
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Center for Nanotechnology, Münster, Germany
| | - Alexander Timmer
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Center for Nanotechnology, Münster, Germany
| | - Zhixin Hu
- Center for Joint Quantum Studies and Department of Physics, Tianjin University, Tianjin, China
| | - Lacheng Liu
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Center for Nanotechnology, Münster, Germany
| | - Oscar Díaz Arado
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Center for Nanotechnology, Münster, Germany
| | - Marvin Cnudde
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Center for Nanotechnology, Münster, Germany
| | - Cristian Alejandro Strassert
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Center for Nanotechnology, Münster, Germany
| | - Wei Ji
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, China
| | - Michael Rohlfing
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Harald Fuchs
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Center for Nanotechnology, Münster, Germany
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37
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Gross L, Schuler B, Pavliček N, Fatayer S, Majzik Z, Moll N, Peña D, Meyer G. Rasterkraftmikroskopie für die molekulare Strukturaufklärung. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201703509] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Leo Gross
- IBM Research - Zürich; 8803 Rüschlikon Schweiz
| | - Bruno Schuler
- IBM Research - Zürich; 8803 Rüschlikon Schweiz
- Molecular Foundry; Lawrence Berkeley National Laboratory; Berkeley CA 94720 USA
| | | | | | | | | | - Diego Peña
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica; Universidade de Santiago de Compostela; Santiago de Compostela 15782 Spanien
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38
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Gross L, Schuler B, Pavliček N, Fatayer S, Majzik Z, Moll N, Peña D, Meyer G. Atomic Force Microscopy for Molecular Structure Elucidation. Angew Chem Int Ed Engl 2018; 57:3888-3908. [DOI: 10.1002/anie.201703509] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/14/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Leo Gross
- IBM Research-Zurich; 8803 Rüschlikon Switzerland
| | - Bruno Schuler
- IBM Research-Zurich; 8803 Rüschlikon Switzerland
- Current address: Molecular Foundry; Lawrence Berkeley National Laboratory; Berkeley CA 94720 USA
| | | | | | - Zsolt Majzik
- IBM Research-Zurich; 8803 Rüschlikon Switzerland
| | - Nikolaj Moll
- IBM Research-Zurich; 8803 Rüschlikon Switzerland
| | - Diego Peña
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica; Universidade de Santiago de Compostela; Santiago de Compostela 15782 Spain
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39
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Niyas MA, Ramakrishnan R, Vijay V, Hariharan M. Structure-Packing-Property Correlation of Self-Sorted Versus Interdigitated Assembly in TTF⋅TCNQ-Based Charge-Transport Materials. Chemistry 2018; 24:12318-12329. [DOI: 10.1002/chem.201705537] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Indexed: 11/09/2022]
Affiliation(s)
- M. A. Niyas
- School of Chemistry; Indian Institute of, Science Education and Research Thiruvananthapuram, Vithura; Thiruvananthapuram 695551 Kerala India
| | - Remya Ramakrishnan
- School of Chemistry; Indian Institute of, Science Education and Research Thiruvananthapuram, Vithura; Thiruvananthapuram 695551 Kerala India
| | - Vishnu Vijay
- School of Chemistry; Indian Institute of, Science Education and Research Thiruvananthapuram, Vithura; Thiruvananthapuram 695551 Kerala India
| | - Mahesh Hariharan
- School of Chemistry; Indian Institute of, Science Education and Research Thiruvananthapuram, Vithura; Thiruvananthapuram 695551 Kerala India
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40
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Liu LK, Lu YJ, Lu N, Li TY, Huang JY, Lin CH, Wen YS, McMillen CD, Thrasher JS. The (2,2′-bipyridine)PtI2 complex with 5,5′-modification of fluorous side chains: Orthogonal skeleton. J Fluor Chem 2018. [DOI: 10.1016/j.jfluchem.2017.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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41
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Scirè A, Annovazzi-Lodi V. Self-organization in a diversity induced thermodynamics. PLoS One 2017; 12:e0188753. [PMID: 29220363 PMCID: PMC5722306 DOI: 10.1371/journal.pone.0188753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 11/12/2017] [Indexed: 11/24/2022] Open
Abstract
In this work we show how global self-organized patterns can come out of a disordered ensemble of point oscillators, as a result of a deterministic, and not of a random, cooperative process. The resulting system dynamics has many characteristics of classical thermodynamics. To this end, a modified Kuramoto model is introduced, by including Euclidean degrees of freedom and particle polarity. The standard deviation of the frequency distribution is the disorder parameter, diversity, acting as temperature, which is both a source of motion and of disorder. For zero and low diversity, robust static phase-synchronized patterns (crystals) appear, and the problem reverts to a generic dissipative many-body problem. From small to moderate diversity crystals display vibrations followed by structure disintegration in a competition of smaller dynamic patterns, internally synchronized, each of which is capable to manage its internal diversity. In this process a huge variety of self-organized dynamic shapes is formed. Such patterns can be seen again as (more complex) oscillators, where the same description can be applied in turn, renormalizing the problem to a bigger scale, opening the possibility of pattern evolution. The interaction functions are kept local because our idea is to build a system able to produce global patterns when its constituents only interact at the bond scale. By further increasing the oscillator diversity, the dynamics becomes erratic, dynamic patterns show short lifetime, and finally disappear for high diversity. Results are neither qualitatively dependent on the specific choice of the interaction functions nor on the shape of the probability function assumed for the frequencies. The system shows a phase transition and a critical behaviour for a specific value of diversity.
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Affiliation(s)
- Alessandro Scirè
- Dipartimento di Ingegneria Industriale e dell’Informazione, Università di Pavia, Via Ferrata 5, I-27100, Pavia, Italy
| | - Valerio Annovazzi-Lodi
- Dipartimento di Ingegneria Industriale e dell’Informazione, Università di Pavia, Via Ferrata 5, I-27100, Pavia, Italy
- * E-mail:
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42
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Jelínek P. High resolution SPM imaging of organic molecules with functionalized tips. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:343002. [PMID: 28749786 DOI: 10.1088/1361-648x/aa76c7] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
One of the most remarkable and exciting achievements in the field of scanning probe microscopy (SPM) in the last years is the unprecedented sub-molecular resolution of both atomic and electronic structures of single molecules deposited on solid state surfaces. Despite its youth, the technique has already brought many new possibilities to perform different kinds of measurements, which cannot be accomplished by other techniques. This opens new perspectives in advanced characterization of physical and chemical processes and properties of molecular structures on surfaces. Here, we discuss the history and recent progress of the high resolution imaging with a functionalized probe by means of atomic force microscopy (AFM), scanning tunnelling microscopy (STM) and inelastic electron tunneling spectroscopy (IETS). We describe the mechanisms responsible for the high-resolution AFM, STM and IETS-STM contrast. The complexity of this technique requires new theoretical approaches, where a relaxation of the functionalized probe is considered. We emphasise the similarities of the mechanism driving high-resolution SPM with other imaging methods. We also summarise briefly significant achievements and progress in different branches. Finally we provide brief perspectives and remaining challenges of the further refinement of these high-resolution methods.
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Affiliation(s)
- Pavel Jelínek
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic
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43
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Patera LL, Liu X, Mosso N, Decurtins S, Liu SX, Repp J. Crystallization of a Two-Dimensional Hydrogen-Bonded Molecular Assembly: Evolution of the Local Structure Resolved by Atomic Force Microscopy. Angew Chem Int Ed Engl 2017; 56:10786-10790. [DOI: 10.1002/anie.201705338] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Laerte L. Patera
- Department of Physics; University of Regensburg; Universitatsstrasse 31 93053 Regensburg Germany
| | - Xunshan Liu
- Department of Chemistry and Biochemistry; University of Bern; Freiestrasse 3 3012 Bern Switzerland
| | - Nico Mosso
- IBM Research-Zurich; Säumerstrasse 4 8803 Rüschlikon Switzerland
| | - Silvio Decurtins
- Department of Chemistry and Biochemistry; University of Bern; Freiestrasse 3 3012 Bern Switzerland
| | - Shi-Xia Liu
- Department of Chemistry and Biochemistry; University of Bern; Freiestrasse 3 3012 Bern Switzerland
| | - Jascha Repp
- Department of Physics; University of Regensburg; Universitatsstrasse 31 93053 Regensburg Germany
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44
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Patera LL, Liu X, Mosso N, Decurtins S, Liu SX, Repp J. Crystallization of a Two-Dimensional Hydrogen-Bonded Molecular Assembly: Evolution of the Local Structure Resolved by Atomic Force Microscopy. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201705338] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Laerte L. Patera
- Department of Physics; University of Regensburg; Universitatsstrasse 31 93053 Regensburg Germany
| | - Xunshan Liu
- Department of Chemistry and Biochemistry; University of Bern; Freiestrasse 3 3012 Bern Switzerland
| | - Nico Mosso
- IBM Research-Zurich; Säumerstrasse 4 8803 Rüschlikon Switzerland
| | - Silvio Decurtins
- Department of Chemistry and Biochemistry; University of Bern; Freiestrasse 3 3012 Bern Switzerland
| | - Shi-Xia Liu
- Department of Chemistry and Biochemistry; University of Bern; Freiestrasse 3 3012 Bern Switzerland
| | - Jascha Repp
- Department of Physics; University of Regensburg; Universitatsstrasse 31 93053 Regensburg Germany
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45
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Schuler B, Zhang Y, Collazos S, Fatayer S, Meyer G, Pérez D, Guitián E, Harper MR, Kushnerick JD, Peña D, Gross L. Characterizing aliphatic moieties in hydrocarbons with atomic force microscopy. Chem Sci 2017; 8:2315-2320. [PMID: 28451335 PMCID: PMC5363392 DOI: 10.1039/c6sc04698c] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/11/2016] [Indexed: 01/01/2023] Open
Abstract
We designed and studied hydrocarbon model compounds by high-resolution noncontact atomic force microscopy. In addition to planar polycyclic aromatic moieties, these novel model compounds feature linear alkyl and cycloaliphatic motifs that exist in most hydrocarbon resources - particularly in petroleum asphaltenes and other petroleum fractions - or in lipids in biological samples. We demonstrate successful intact deposition by sublimation of the alkyl-aromatics, and differentiate aliphatic moieties from their aromatic counterparts which were generated from the former by atomic manipulation. The characterization by AFM in combination with atomic manipulation provides clear fingerprints of the aromatic and aliphatic moieties that will facilitate their assignment in a priori unknown samples.
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Affiliation(s)
- Bruno Schuler
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland .
| | - Yunlong Zhang
- ExxonMobil Research and Engineering Company , Annandale , NJ 08801 , USA .
| | - Sara Collazos
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) , Departamento de Química Orgánica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain .
| | - Shadi Fatayer
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland .
| | - Gerhard Meyer
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland .
| | - Dolores Pérez
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) , Departamento de Química Orgánica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain .
| | - Enrique Guitián
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) , Departamento de Química Orgánica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain .
| | - Michael R Harper
- ExxonMobil Research and Engineering Company , Annandale , NJ 08801 , USA .
| | | | - Diego Peña
- Centro de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) , Departamento de Química Orgánica , Universidade de Santiago de Compostela , Santiago de Compostela 15782 , Spain .
| | - Leo Gross
- IBM Research - Zurich , Säumerstrasse 4 , 8803 Rüschlikon , Switzerland .
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46
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Dong Y, Svane K, Lemay JC, Groves MN, McBreen PH. STM Study of Ketopantolactone/(R)-1-(1-Naphthyl)ethylamine Complexes on Pt(111): Comparison of Prochiral and Enantiomeric Ratios and Examination of the Contribution of CH···OC Bonding. ACS Catal 2017. [DOI: 10.1021/acscatal.6b02590] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yi Dong
- Department of Chemistry, Laval University, Quebec City, Quebec G1V 0A6, Canada
| | - Katrine Svane
- Department of Chemistry, University of Bath, Bath BA2 7AY, U.K
| | | | - Michael N. Groves
- Department of Chemistry and Biochemistry, California State University, Fullerton, Fullerton, California 92834, United States
| | - Peter H. McBreen
- Department of Chemistry, Laval University, Quebec City, Quebec G1V 0A6, Canada
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47
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Mali KS, Pearce N, De Feyter S, Champness NR. Frontiers of supramolecular chemistry at solid surfaces. Chem Soc Rev 2017; 46:2520-2542. [DOI: 10.1039/c7cs00113d] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Supramolecular chemistry on solid surfaces represents an exciting field of research that continues to develop in new and unexpected directions.
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Affiliation(s)
- Kunal S. Mali
- Division of Molecular Imaging and Photonics
- Department of Chemistry
- KU Leuven – University of Leuven
- B3001 Leuven
- Belgium
| | | | - Steven De Feyter
- Division of Molecular Imaging and Photonics
- Department of Chemistry
- KU Leuven – University of Leuven
- B3001 Leuven
- Belgium
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48
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Pfeiffer CR, Pearce N, Champness NR. Complexity of two-dimensional self-assembled arrays at surfaces. Chem Commun (Camb) 2017; 53:11528-11539. [DOI: 10.1039/c7cc06110b] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The developing field of complexity in self-assembled systems on surfaces is discussed.
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49
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Lübbe J, Temmen M, Rahe P, Reichling M. Noise in NC-AFM measurements with significant tip-sample interaction. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:1885-1904. [PMID: 28144538 PMCID: PMC5238627 DOI: 10.3762/bjnano.7.181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
The frequency shift noise in non-contact atomic force microscopy (NC-AFM) imaging and spectroscopy consists of thermal noise and detection system noise with an additional contribution from amplitude noise if there are significant tip-sample interactions. The total noise power spectral density DΔf (fm) is, however, not just the sum of these noise contributions. Instead its magnitude and spectral characteristics are determined by the strongly non-linear tip-sample interaction, by the coupling between the amplitude and tip-sample distance control loops of the NC-AFM system as well as by the characteristics of the phase locked loop (PLL) detector used for frequency demodulation. Here, we measure DΔf (fm) for various NC-AFM parameter settings representing realistic measurement conditions and compare experimental data to simulations based on a model of the NC-AFM system that includes the tip-sample interaction. The good agreement between predicted and measured noise spectra confirms that the model covers the relevant noise contributions and interactions. Results yield a general understanding of noise generation and propagation in the NC-AFM and provide a quantitative prediction of noise for given experimental parameters. We derive strategies for noise-optimised imaging and spectroscopy and outline a full optimisation procedure for the instrumentation and control loops.
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Affiliation(s)
- Jannis Lübbe
- Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany
| | - Matthias Temmen
- Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany
| | - Philipp Rahe
- Department of Physics and Astronomy, The University of Utah, 115 South 1400 East, Salt Lake City, UT 84112-0830, USA
- now at: School of Physics & Astronomy, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Michael Reichling
- Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany
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50
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Xin X, Gan LY, Van Hove MA, Ren X, Wang H, Guo CS, Zhao Y. Exploring Molecules beyond CO as Tip Functionalizations in High-Resolution Noncontact Atomic Force Microscopy: A First Principles Approach. ACS OMEGA 2016; 1:1004-1009. [PMID: 31457178 PMCID: PMC6640759 DOI: 10.1021/acsomega.6b00168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/09/2016] [Indexed: 06/10/2023]
Abstract
Atomic resolution of molecules has been achieved using noncontact atomic force microscopy (AFM) with the key step to functionalize the tip apex by attaching suitable molecules so as to achieve high spatial resolution through a sharper tip. A few molecular terminations have been explored theoretically and experimentally, and they exhibit various imaging behaviors. Here, we explore the influence of the structures and chemical compositions of various molecular candidates as tips on the contrast of AFM images by a first principles approach. Our results reveal that the two end atoms of a linear molecule terminating nearest the sample dominate the imaging behaviors, for example, atomic resolution, sharpness, distortion, and so forth, whereas the symmetry of the termination plays an important role in the distortion of AFM images. These findings suggest that new tip terminations can be engineered by decoupling the three end atoms responsible for imaging behaviors from the tip structure behind them, which is attached to the macro tip apex.
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Affiliation(s)
- Xiaojun Xin
- Key
Laboratory of Advanced Technology of Materials (Ministry of Education),
Superconductivity and New Energy R&D Center and School of Physical Science and
Technology, Southwest Jiaotong University, Chengdu 610031, Sichuan, China
| | - Li-Yong Gan
- Key
Laboratory of Advanced Technology of Materials (Ministry of Education),
Superconductivity and New Energy R&D Center and School of Physical Science and
Technology, Southwest Jiaotong University, Chengdu 610031, Sichuan, China
| | - Michel A. Van Hove
- Institute
of Computational and Theoretical Studies and Department of Physics, Hong Kong Baptist University, Kowloon, Hong Kong Special Administrative
Region
| | - Xinguo Ren
- Key Laboratory of Quantum Information and Synergistic Innovation Center of
Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Hongyan Wang
- Key
Laboratory of Advanced Technology of Materials (Ministry of Education),
Superconductivity and New Energy R&D Center and School of Physical Science and
Technology, Southwest Jiaotong University, Chengdu 610031, Sichuan, China
| | - Chun-Sheng Guo
- Key
Laboratory of Advanced Technology of Materials (Ministry of Education),
Superconductivity and New Energy R&D Center and School of Physical Science and
Technology, Southwest Jiaotong University, Chengdu 610031, Sichuan, China
| | - Yong Zhao
- Key
Laboratory of Advanced Technology of Materials (Ministry of Education),
Superconductivity and New Energy R&D Center and School of Physical Science and
Technology, Southwest Jiaotong University, Chengdu 610031, Sichuan, China
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