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Bi H, Palma CA, Gong Y, Hasch P, Elbing M, Mayor M, Reichert J, Barth JV. Voltage-Driven Conformational Switching with Distinct Raman Signature in a Single-Molecule Junction. J Am Chem Soc 2018; 140:4835-4840. [DOI: 10.1021/jacs.7b12818] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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77
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Delarue Bizzini L, Müntener T, Häussinger D, Neuburger M, Mayor M. Synthesis of trinorbornane. Chem Commun (Camb) 2018; 53:11399-11402. [PMID: 28975933 DOI: 10.1039/c7cc06273g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report the synthesis and characterisation of the until recently unreported chiral C11 skeleton of tetracyclo[5.2.2.01,6.04,9]undecane ("trinorbornane") which could be obtained in 7% overall yield in 9 steps. This new rigid structural type was found to be present in the computer generated Chemical Universe Data-base (GDB) and has until now no real-world counterpart.
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Karamzadeh B, Eaton T, Torres DM, Cebula I, Mayor M, Buck M. Sequential nested assembly at the liquid/solid interface. Faraday Discuss 2017; 204:173-190. [PMID: 28782775 DOI: 10.1039/c7fd00115k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Studying the stepwise assembly of a four component hybrid structure on Au(111)/mica, the pores of a hydrogen bonded bimolecular network of 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) and 1,3,5-triazine-2,4,6-triamine (melamine) were partitioned by three and four-armed molecules based on oligo([biphenyl]-4-ylethynyl)benzene, followed by the templated adsorption of either C60 fullerene or adamantane thiol molecules. The characterisation by ambient scanning tunneling microscopy (STM) reveals that the pore modifiers exhibit dynamics which pronouncedly depend on the molecular structure. The three-armed molecule 1,3,5-tris([1,1'-biphenyl]-4-ylethynyl)benzene (3BPEB) switches between two symmetry equivalent configurations on a time scale fast compared to the temporal resolution of the STM. Derivatisation of 3BPEB by hydroxyl groups substantially reduces the switching rate. For the four-armed molecule configurational changes are observed only occasionally. The observation of isolated fullerenes and small clusters of adamantane thiol molecules, which are arranged in a characteristic fashion, reveals the templating effect of the trimolecular supramolecular network. However, the fraction of compartments filled by guest molecules is significantly below one for both the thermodynamically controlled adsorption of C60 and the kinetically controlled adsorption of the thiol with the latter causing partial removal of the pore modifier. The experiments, on the one hand, demonstrate the feasibility of templating by nested assembly but, on the other hand, also pinpoint the requirement for the energy landscape to be tolerant to variations in the assembly process.
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79
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Valášek M, Mayor M. Frontispiece: Spatial and Lateral Control of Functionality by Rigid Molecular Platforms. Chemistry 2017. [DOI: 10.1002/chem.201785561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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80
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Valášek M, Mayor M. Spatial and Lateral Control of Functionality by Rigid Molecular Platforms. Chemistry 2017; 23:13538-13548. [PMID: 28766790 DOI: 10.1002/chem.201703349] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 11/11/2022]
Abstract
Surface mounted molecular devices have received significant attention in the scientific community because of their unique ability to construct functional materials. The key involves the platform on which the molecular device works on solid substrates, such as in solid-liquid or solid-vacuum interfaces. Here, we outline the concept of rigid molecular platforms to immobilize active functionality atop flat surfaces in a controllable manner. Most of these (multipodal) platforms have at least three anchoring groups to control the spatial arrangement of the protruding functional moieties and form mechanically stable and electronically tuned contacts to the underlying substrate. Another approach is based on employing of flat aromatic scaffolds bearing perpendicular functionalities that form stable lateral assemblies on various surfaces. Emphasis is placed on the need for controllable assembly and separation of these tailor-made molecules that expose functionalities at the molecular scale. The discussions are focused on the different molecular designs realizing functional 3D architectures on surfaces, the role of various anchoring strategies to control the spatial arrangement, and structural considerations controlling physical features like the coupling to the surface or the available space for sterically demanding molecular operations.
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Schätti J, Sezer U, Pedalino S, Cotter JP, Arndt M, Mayor M, Köhler V. Tailoring the volatility and stability of oligopeptides. JOURNAL OF MASS SPECTROMETRY : JMS 2017; 52:550-556. [PMID: 28608445 PMCID: PMC5601229 DOI: 10.1002/jms.3959] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 06/07/2023]
Abstract
Amino acids are essential building blocks of life, and fluorinated derivatives have gained interest in chemistry and medicine. Modern mass spectrometry has enabled the study of oligo- and polypeptides as isolated entities in the gas phase, but predominantly as singly or even multiply charged species. While laser desorption of neutral peptides into adiabatically expanding supersonic noble gas jets is possible, UV-VIS spectroscopy, electric or magnetic deflectometry as well as quantum interferometry would profit from the possibility to prepare thermally slow molecular beams. This has typically been precluded by the fragility of the peptide bond and the fact that a peptide would rather 'fry', i.e. denature and fragment than 'fly'. Here, we explore how tailored perfluoroalkyl functionalization can reduce the intermolecular binding and thus increase the volatility of peptides and compare it to previously explored methylation, acylation and amidation of peptides. We show that this strategy is essential and enables the formation of thermal beams of intact neutral tripeptides, whereas only fragments were observed for an extensively fluoroalkyl-decorated nonapeptide. © 2017 The Authors. Journal of Mass Spectrometry Published by John Wiley & Sons Ltd.
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Aeschi Y, Drayss-Orth S, Valášek M, Raps F, Häussinger D, Mayor M. Assembly of [2]Rotaxanes in Water. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700640] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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83
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Le Pleux L, Kapatsina E, Hildesheim J, Häussinger D, Mayor M. A Molecular Turnstile as an E
-Field-Triggered Single-Molecule Switch: Concept and Synthesis. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700318] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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84
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Lindner M, Valášek M, Mayor M, Frauhammer T, Wulfhekel W, Gerhard L. Molekulares Kästchenpapier. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703586] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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85
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Lindner M, Valášek M, Mayor M, Frauhammer T, Wulfhekel W, Gerhard L. Molecular Graph Paper. Angew Chem Int Ed Engl 2017; 56:8290-8294. [PMID: 28544167 DOI: 10.1002/anie.201703586] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Indexed: 11/10/2022]
Abstract
We present a self-assembled template that consists of tetraphenylmethane derivatives and adopts a periodic lateral arrangement on a Au(111) surface with acetyl groups sticking out of the molecular film. By using the tip of a scanning tunneling microscope, these acetyl groups can be removed in a spatially controlled way without significantly affecting the remaining molecular assembly. The chemically modified molecules can be readily distinguished from the original ones such that information can be engraved in the molecular film. Both the modified nature of an individual molecule and the order of the molecular film are shown to persist at room temperature. The mesh size of this molecular graph paper can be tuned by varying the length of the molecular spacer so that writing and reading information on the nanoscale with variable letter sizes becomes possible.
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Gerhard L, Edelmann K, Homberg J, Valášek M, Bahoosh SG, Lukas M, Pauly F, Mayor M, Wulfhekel W. An electrically actuated molecular toggle switch. Nat Commun 2017; 8:14672. [PMID: 28276442 PMCID: PMC5347093 DOI: 10.1038/ncomms14672] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 01/23/2017] [Indexed: 01/28/2023] Open
Abstract
Molecular electronics is considered a promising approach for future nanoelectronic devices. In order that molecular junctions can be used as electrical switches or even memory devices, they need to be actuated between two distinct conductance states in a controlled and reproducible manner by external stimuli. Here we present a tripodal platform with a cantilever arm and a nitrile group at its end that is lifted from the surface. The formation of a coordinative bond between the nitrile nitrogen and the gold tip of a scanning tunnelling microscope can be controlled by both electrical and mechanical means, and leads to a hysteretic switching of the conductance of the junction by more than two orders of magnitude. This toggle switch can be actuated with high reproducibility so that the forces involved in the mechanical deformation of the molecular cantilever can be determined precisely with scanning tunnelling microscopy. Robust molecular junctions demand highly reproducible switching between two or more well-defined conductance states upon control. Here, Gerhard et al. show the utility of elastic deformation of tripodal spirobifluorene derivatives in the junction of a scanning tunnelling microscope to achieve this goal.
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Lehmann M, Peters EH, Mayor M. Size Matters: Influence of Gold-to-Ligand Ratio and Sulfur-Sulfur Distance of Linear Thioether Heptamers on the Size of Gold Nanoparticles. Helv Chim Acta 2017. [DOI: 10.1002/hlca.201600395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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88
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Hoffmann V, le Pleux L, Häussinger D, Unke OT, Prescimone A, Mayor M. Deltoid versus Rhomboid: Controlling the Shape of Bis-ferrocene Macrocycles by the Bulkiness of the Substituents. Organometallics 2017. [DOI: 10.1021/acs.organomet.6b00909] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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89
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Sezer U, Geyer P, Kriegleder M, Debiossac M, Shayeghi A, Arndt M, Felix L, Mayor M. Selective photodissociation of tailored molecular tags as a tool for quantum optics. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:325-333. [PMID: 28243571 PMCID: PMC5301912 DOI: 10.3762/bjnano.8.35] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 01/17/2017] [Indexed: 06/06/2023]
Abstract
Recent progress in synthetic chemistry and molecular quantum optics has enabled demonstrations of the quantum mechanical wave-particle duality for complex particles, with masses exceeding 10 kDa. Future experiments with even larger objects will require new optical preparation and manipulation methods that shall profit from the possibility to cleave a well-defined molecular tag from a larger parent molecule. Here we present the design and synthesis of two model compounds as well as evidence for the photoinduced beam depletion in high vacuum in one case.
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Abstract
Chiral non-planar polyaromatic systems that display zero, positive or negative Gaussian curvature are analysed and their potential to ‘encode’ chirality of larger sp2-carbon allotropes is evaluated. Shown is a hypothetical peanut-shaped carbon allotrope, where helical chirality results from the interplay of various curvature types.
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Rickhaus M, Mayor M, Juríček M. Strain-induced helical chirality in polyaromatic systems. Chem Soc Rev 2016; 45:1542-56. [PMID: 26765050 DOI: 10.1039/c5cs00620a] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Helicity in a molecule arises when the molecule contains a stereogenic axis instead of a stereogenic centre. In a molecule that is not inherently helically chiral, helicity can be induced by designing the molecule such that an unfavourable steric interaction, or strain, is present in its planar conformation. The release of this strain forces the molecule to adopt a helical twist against the cost of the torsional strain induced in the backbone, an interplay of forces, which must be balanced in favour of the helical conformation over the planar one. In this tutorial review, design principles that govern this process are analysed and the selected examples are categorised into three main (I, II and III) and two related (IV and V) classes, simply by their relation to one of the three types of helically twisted ribbons or two types of helically twisted cyclic ribbons, respectively. The presented examples were selected such that they illustrate their category in the best possible way, as well as based on availability of their solid-state structures and racemisation energy barriers. Finally, the relationship between the structure and properties is discussed, highlighting the cases in which induced helicity gave rise to unprecedented phenomena.
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Frisenda R, Harzmann GD, Celis Gil JA, Thijssen JM, Mayor M, van der Zant HSJ. Stretching-Induced Conductance Increase in a Spin-Crossover Molecule. NANO LETTERS 2016; 16:4733-7. [PMID: 27088578 DOI: 10.1021/acs.nanolett.5b04899] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We investigate transport through mechanically triggered single-molecule switches that are based on the coordination sphere-dependent spin state of Fe(II)-species. In these molecules, in certain junction configurations the relative arrangement of two terpyridine ligands within homoleptic Fe(II)-complexes can be mechanically controlled. Mechanical pulling may thus distort the Fe(II) coordination sphere and eventually modify their spin state. Using the movable nanoelectrodes in a mechanically controlled break-junction at low temperature, current-voltage measurements at cryogenic temperatures support the hypothesized switching mechanism based on the spin-crossover behavior. A large fraction of molecular junctions formed with the spin-crossover-active Fe(II)-complex displays a conductance increase for increasing electrode separation and this increase can reach 1-2 orders of magnitude. Theoretical calculations predict a stretching-induced spin transition in the Fe(II)-complex and a larger transmission for the high-spin configuration.
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Lindner M, Valášek M, Homberg J, Edelmann K, Gerhard L, Wulfhekel W, Fuhr O, Wächter T, Zharnikov M, Kolivoška V, Pospíšil L, Mészáros G, Hromadová M, Mayor M. Importance of the Anchor Group Position (ParaversusMeta) in Tetraphenylmethane Tripods: Synthesis and Self-Assembly Features. Chemistry 2016; 22:13218-35. [DOI: 10.1002/chem.201602019] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Indexed: 11/06/2022]
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94
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Su PY, Chen YF, Liu JM, Xiao LM, Kuang DB, Mayor M, Su CY. Hydrophobic Hole-Transporting Materials Incorporating Multiple Thiophene Cores with Long Alkyl Chains for Efficient Perovskite Solar Cells. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.05.122] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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95
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Puebla-Hellmann G, Mayor M, Lörtscher E. Functional Nanopores: A Solid-state Concept for Artificial Reaction Compartments and Molecular Factories. Chimia (Aarau) 2016; 70:432-8. [PMID: 27363373 DOI: 10.2533/chimia.2016.432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
On the road towards the long-term goal of the NCCR Molecular Systems Engineering to create artificial molecular factories, we aim at introducing a compartmentalization strategy based on solid-state silicon technology targeting zeptoliter reaction volumes and simultaneous electrical contact to ensembles of well-oriented molecules. This approach allows the probing of molecular building blocks under a controlled environment prior to their use in a complex molecular factory. Furthermore, these ultra-sensitive electrical conductance measurements allow molecular responses to a variety of external triggers to be used as sensing and feedback mechanisms. So far, we demonstrate the proof-of-concept by electrically contacting self-assembled mono-layers of alkane-dithiols as an established test system. Here, the molecular films are laterally constrained by a circular dielectric confinement, forming a so-called 'nanopore'. Device yields above 85% are consistently achieved down to sub-50 nm nanopore diameters. This generic platform will be extended to create distributed, cascaded reactors with individually addressable reaction sites, including interconnecting micro-fluidic channels for electrochemical communication among nanopores and sensing sites for reaction control and feedback. In this scientific outlook, we will sketch how such a solid-state nanopore concept can be used to study various aspects of molecular compounds tailored for operation in a molecular factory.
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Karimi MA, Bahoosh SG, Valášek M, Bürkle M, Mayor M, Pauly F, Scheer E. Identification of the current path for a conductive molecular wire on a tripodal platform. NANOSCALE 2016; 8:10582-10590. [PMID: 27163116 DOI: 10.1039/c5nr08708b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present the chemical synthesis as well as charge transport measurements and calculations for a new tripodal platform based on a rigid 9,9'-spirobifluorene equipped with a phenylene-ethynylene wire. The transport experiments are performed with the help of the low-temperature mechanically controlled break junction technique with gold electrodes. By combining experimental and theoretical investigations of elastic and inelastic charge transport, we show that the current proceeds through the designated molecular wire and identify a binding geometry that is compatible with the experimental observations. The conductive molecular wire on the platform features a well-defined and relatively high conductance of the order of 10(-3)G0 despite the length of the current path of more than 1.7 nm, demonstrating that this platform is suitable to incorporate functional units like molecular switches or sensors.
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Hoffmann V, Jenny N, Häussinger D, Neuburger M, Mayor M. Rotationally Restricted 1,1′-Bis(phenylethynyl)ferrocene Subunits in Macrocycles. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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98
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Rickhaus M, Jundt L, Mayor M. Determining Inversion Barriers in Atrop- isomers – A Tutorial for Organic Chemists. Chimia (Aarau) 2016; 70:192-202. [DOI: 10.2533/chimia.2016.192] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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99
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Valášek M, Lindner M, Mayor M. Rigid multipodal platforms for metal surfaces. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:374-405. [PMID: 27335731 PMCID: PMC4901557 DOI: 10.3762/bjnano.7.34] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 02/17/2016] [Indexed: 06/05/2023]
Abstract
In this review the recent progress in molecular platforms that form rigid and well-defined contact to a metal surface are discussed. Most of the presented examples have at least three anchoring units in order to control the spatial arrangement of the protruding molecular subunit. Another interesting feature is the lateral orientation of these foot structures which, depending on the particular application, is equally important as the spatial arrangement of the molecules. The numerous approaches towards assembling and organizing functional molecules into specific architectures on metal substrates are reviewed here. Particular attention is paid to variations of both, the core structures and the anchoring groups. Furthermore, the analytical methods enabling the investigation of individual molecules as well as monomolecular layers of ordered platform structures are summarized. The presented multipodal platforms bearing several anchoring groups form considerably more stable molecule-metal contacts than corresponding monopodal analogues and exhibit an enlarged separation of the functional molecules due to the increased footprint, as well as restrict tilting of the functional termini with respect to the metal surface. These platforms are thus ideally suited to tune important properties of the molecule-metal interface. On a single-molecule level, several of these platforms enable the control over the arrangement of the protruding rod-type molecular structures (e.g., molecular wires, switches, rotors, sensors) with respect to the surface of the substrate.
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100
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Lehmann M, Peters EH, Mayor M. Linear Tetraphenylmethane-Based Thioether Oligomers Stabilising an Entire Gold Nanoparticle by Enwrapping. Chemistry 2016; 22:2261-5. [PMID: 26690321 DOI: 10.1002/chem.201504575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Indexed: 11/05/2022]
Abstract
The design and synthesis of a novel linear thioether-based ligand subunit with a tetraphenylmethane core used in the stabilisation of gold nanoparticles (AuNPs) are presented. Mono-, tri, penta- and heptamers of the ligand have been synthesised and used to stabilise AuNPs by enwrapping. With the exception of the monomer, all ligands provide reliable long-term stability and redispersibility for the coated nanoparticles in common organic solvents. Despite variation of the oligomer length, all stable particles were of the same size within error tolerance (1.16±0.32 nm for the trimer, 1.15±0.30 nm for the pentamer, 1.17±0.34 nm for the heptamer), as investigated by transmission electron microscopy (TEM). These findings suggest that not only the number of sulfur atoms in the ligand, but also its bulkiness play a crucial role in stabilising the AuNPs. These findings are supported by thermogravimetric analysis (TGA), showing that AuNPs stabilised by the penta- or heptamer are passivated by a single ligand. Thermal stability measurements suggest a correlation between ligand coverage and thermal stability, further supporting these findings.
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