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Sidler E, Malinčík J, Prescimone A, Mayor M. Induced axial chirality by a tight belt: naphthalene chromophores fixed in a 2,5-substituted cofacial para-phenylene-ethynylene framework. JOURNAL OF MATERIALS CHEMISTRY. C 2021; 9:16199-16207. [PMID: 34912562 PMCID: PMC8614465 DOI: 10.1039/d1tc02180j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 07/28/2021] [Indexed: 06/14/2023]
Abstract
We report the design of a synthetically easy accessible axial chirality-inducing framework for a chromophore of choice. The scaffold consists of two basic para-phenylene-ethynylene backbones separated by laterally placed corner units. Substitution with an inherently achiral chromophore at the 2 and 5 positions of the central phenylene excitonically couples the chromophore associated transition and thereby results in chiroptical properties. Using 6-methoxynaphthalene as a model chromophore, we present the synthesis, structural analysis and spectroscopic investigation of the framework. The chiral framework was synthesized in three straightforward synthetic steps and fully characterized. The obtained racemic compounds were resolved using HPLC and assignment of the absolute configuration was performed using the exciton chirality method, crystallography and DFT calculations. This simple yet potent framework might prove useful to enrich the structural diversity of chiral materials.
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Pyurbeeva E, Hsu C, Vogel D, Wegeberg C, Mayor M, van der Zant H, Mol JA, Gehring P. Controlling the Entropy of a Single-Molecule Junction. NANO LETTERS 2021; 21:9715-9719. [PMID: 34766782 DOI: 10.1021/acs.nanolett.1c03591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Single molecules are nanoscale thermodynamic systems with few degrees of freedom. Thus, the knowledge of their entropy can reveal the presence of microscopic electron transfer dynamics that are difficult to observe otherwise. Here, we apply thermocurrent spectroscopy to directly measure the entropy of a single free radical molecule in a magnetic field. Our results allow us to uncover the presence of a singlet to triplet transition in one of the redox states of the molecule, not detected by conventional charge transport measurements. This highlights the power of thermoelectric measurements which can be used to determine the difference in configurational entropy between the redox states of a nanoscale system involved in conductance without any prior assumptions about its structure or microscopic dynamics.
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Zwick P, Dulić D, van der Zant HSJ, Mayor M. Porphyrins as building blocks for single-molecule devices. NANOSCALE 2021; 13:15500-15525. [PMID: 34558586 PMCID: PMC8485416 DOI: 10.1039/d1nr04523g] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 08/19/2021] [Indexed: 05/23/2023]
Abstract
Direct measurement of single-molecule electrical transparency by break junction experiments has become a major field of research over the two last decades. This review specifically and comprehensively highlights the use of porphyrins as molecular components and discusses their potential use for the construction of future devices. Throughout the review, the features provided by porphyrins, such as low level misalignments and very low attenuation factors, are shown with numerous examples, illustrating the potential and limitations of these molecular junctions, as well as differences emerging from applied integration/investigation techniques.
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Dekkiche H, Malinčik J, Prescimone A, Häussinger D, Mayor M. An Ortho-Tetraphenylene-Based "Geländer" Architecture Consisting Exclusively of 52 sp 2 -Hybridized C Atoms. Chemistry 2021; 27:13258-13267. [PMID: 34254710 PMCID: PMC8518721 DOI: 10.1002/chem.202101968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Indexed: 11/28/2022]
Abstract
A new type of "Geländer" molecule based on a ortho-tetraphenylene core is presented. The central para-quaterphenyl backbone is wrapped by a 4,4'-di((Z)-styryl)-1,1'-biphenyl banister, with its aryl rings covalently attached to all four phenyl rings of the backbone. The resulting helical chiral bicyclic architecture consists exclusively of sp2 -hybridized carbon atoms. The target structure was assembled by expanding the central ortho-tetraphenylene subunit with the required additional phenyl rings followed by a twofold macrocyclization. The first macrocyclization attempts based on a twofold McMurry coupling were successful but low yielding; the second strategy, profiting from olefin metathesis, provided satisfying yields. Hydrogenation of the olefins resulted in a saturated derivative of similar topology, thereby allowing the interdependence between saturation and physico-chemical properties to be studied. The target structures, including their solid-state structures, were fully characterized. The helical chiral bicycle was synthesized as a racemate and separated into pure enantiomers by HPLC on a chiral stationary phase. Comparison of recorded and simulated chiroptical properties allowed the enantiomers to be assigned.
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Reznikova K, Hsu C, Schosser WM, Gallego A, Beltako K, Pauly F, van der Zant HSJ, Mayor M. Substitution Pattern Controlled Quantum Interference in [2.2]Paracyclophane-Based Single-Molecule Junctions. J Am Chem Soc 2021; 143:13944-13951. [PMID: 34424713 PMCID: PMC8414552 DOI: 10.1021/jacs.1c06966] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Indexed: 01/25/2023]
Abstract
Quantum interference (QI) of electron waves passing through a single-molecule junction provides a powerful means to influence its electrical properties. Here, we investigate the correlation between substitution pattern, conductance, and mechanosensitivity in [2.2]paracyclophane (PCP)-based molecular wires in a mechanically controlled break junction experiment. The effect of the meta versus para connectivity in both the central PCP core and the phenyl ring connecting the terminal anchoring group is studied. We find that the meta-phenyl-anchored PCP yields such low conductance levels that molecular features cannot be resolved; in the case of para-phenyl-coupled anchoring, however, large variations in conductance values for modulations of the electrode separation occur for the pseudo-para-coupled PCP core, while this mechanosensitivity is absent for the pseudo-meta-PCP core. The experimental findings are interpreted in terms of QI effects between molecular frontier orbitals by theoretical calculations based on density functional theory and the Landauer formalism.
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Balzer N, Lukášek J, Valášek M, Rai V, Sun Q, Gerhard L, Wulfhekel W, Mayor M. Synthesis and Surface Behaviour of NDI Chromophores Mounted on a Tripodal Scaffold: Towards Self-Decoupled Chromophores for Single-Molecule Electroluminescence. Chemistry 2021; 27:12144-12155. [PMID: 34152041 PMCID: PMC8457086 DOI: 10.1002/chem.202101264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Indexed: 12/01/2022]
Abstract
This paper reports the efficient synthesis, absorption and emission spectra, and the electrochemical properties of a series of 2,6-disubstituted naphthalene-1,4,5,8-tetracarboxdiimide (NDI) tripodal molecules with thioacetate anchors for their surface investigations. Our studies showed that, in particular, the pyrrolidinyl group with its strong electron-donating properties enhanced the fluorescence of such core-substituted NDI chromophores and caused a significant bathochromic shift in the absorption spectrum with a correspondingly narrowed bandgap of 1.94 eV. Cyclic voltammetry showed the redox properties of NDIs to be influenced by core substituents. The strong electron-donating character of pyrrolidine substituents results in rather high HOMO and LUMO levels of -5.31 and -3.37 eV when compared with the parental unsubstituted NDI. UHV-STM measurements of a sub-monolayer of the rigid tripodal NDI chromophores spray deposited on Au(111) show that these molecules mainly tend to adsorb flat in a pairwise fashion on the surface and form unordered films. However, the STML experiments also revealed a few molecular clusters, which might consist of upright oriented molecules protruding from the molecular island and show electroluminescence photon spectra with high electroluminescence yields of up to 6×10-3 . These results demonstrate the promising potential of the NDI tripodal chromophores for the fabrication of molecular devices profiting from optical features of the molecular layer.
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Scherrer D, Vogel D, Drechsler U, Olziersky A, Sparr C, Mayor M, Lörtscher E. Reaktionsverfolgung von Festphasensynthesen in selbstassemblierenden Monolagen mit oberflächenverstärkter Raman‐Spektroskopie. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102319] [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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Scherrer D, Vogel D, Drechsler U, Olziersky A, Sparr C, Mayor M, Lörtscher E. Monitoring Solid-Phase Reactions in Self-Assembled Monolayers by Surface-Enhanced Raman Spectroscopy. Angew Chem Int Ed Engl 2021; 60:17981-17988. [PMID: 34048139 PMCID: PMC8456949 DOI: 10.1002/anie.202102319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 05/18/2021] [Indexed: 12/27/2022]
Abstract
Nanopatterned surfaces enhance incident electromagnetic radiation and thereby enable the detection and characterization of self-assembled monolayers (SAMs), for instance in surface-enhanced Raman spectroscopy (SERS). Herein, Au nanohole arrays, developed and characterized as SERS substrates, are exemplarily used for monitoring a solid-phase deprotection and a subsequent copper(I)-catalyzed azide-alkyne cycloaddition "click" reaction, performed directly on the corresponding SAMs. The SERS substrate was found to be highly reliable in terms of signal reproducibility and chemical stability. Furthermore, the intermediates and the product of the solid-phase synthesis were identified by SERS. The spectra of the immobilized compounds showed minor differences compared to spectra of the microcrystalline solids. With its uniform SERS signals and the high chemical stability, the platform paves the way for monitoring molecular manipulations in surface functionalization applications.
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Vladyka A, Perrin ML, Overbeck J, Ferradás RR, García-Suárez V, Gantenbein M, Brunner J, Mayor M, Ferrer J, Calame M. Author Correction: In-situ formation of one-dimensional coordination polymers in molecular junctions. Nat Commun 2021; 12:4072. [PMID: 34183655 PMCID: PMC8238958 DOI: 10.1038/s41467-021-24204-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Peters EH, Mayor M. Monofunctionalized Gold Nanoparticles: Fabrication and Applications. Chimia (Aarau) 2021; 75:414-426. [PMID: 34016235 DOI: 10.2533/chimia.2021.414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
An overview of various approaches to synthesize gold nanoparticles (AuNPs) bearing one single chemically addressable unit and their diverse fields of application is presented. This comprehensive review not only describes the strategies pursued to obtain monofunctionalized AuNPs, but also reports their behavior as 'massive' molecules in wet chemical protocols and the scope of their applications. The latter reaches from site-specific labels in biomolecules over mechanical barriers in superstructures to building blocks in hybrid nano-architectures. The complementing physical properties of AuNPs combined with precise chemical control of their attachment makes these objects promising building blocks for numerous proof-of-concept experiments and applications.
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Xu L, Valášek M, Hennrich F, Fischer R, Kappes MM, Mayor M. Degradable Fluorene- and Carbazole-Based Copolymers for Selective Extraction of Semiconducting Single-Walled Carbon Nanotubes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bannwart LM, Müntener T, Rickhaus M, Jundt L, Häussinger D, Mayor M. Bicyclic Phenyl-Ethynyl Architectures: Synthesis of a 1,4-Bis(phenylbuta-1,3-diyn-1-yl) Benzene Banister. Chemistry 2021; 27:6295-6307. [PMID: 33502051 PMCID: PMC8048618 DOI: 10.1002/chem.202005207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Indexed: 01/09/2023]
Abstract
The novel diacetylene bridged terphenylic macrocycle 1 is presented and discussed in the context of rotationally restricted "Geländer" oligomers. The 1,4-bis(phenylbuta-1,3-diyn-1-yl) benzene bridge of diacetylene 1 is significantly longer than its terphenyl backbone, forcing the bridge to bend around the central pylon. The synthesis of molecule 1 is based to a large extent on acetylene scaffolding strategies, profiting from orthogonal alkyne protection groups to close both macrocyclic subunits by oxidative acetylene coupling sequentially. The spatial arrangement and the dynamic enantiomerization process of the bicyclic target structure 1 are analyzed. In-depth NMR investigations not only reveal an unexpected spatial arrangement with both oligomer strands bent alongside the backbone, but also display the limited stability of the model compound in the presence of molecular oxygen.
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Xu L, Valášek M, Hennrich F, Sedghamiz E, Penaloza-Amion M, Häussinger D, Wenzel W, Kappes MM, Mayor M. Enantiomeric Separation of Semiconducting Single-Walled Carbon Nanotubes by Acid Cleavable Chiral Polyfluorene. ACS NANO 2021; 15:4699-4709. [PMID: 33626282 DOI: 10.1021/acsnano.0c09235] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Helical wrapping by conjugated polymer has been demonstrated as a powerful tool for the sorting of single-walled carbon nanotubes (SWCNTs) according to their electronic type, chiral index, and even handedness. However, a method of one-step extraction of left-handed (M) and right-handed (P) semiconducting SWCNTs (s-SWCNTs) with subsequent cleavage of the polymer has not yet been published. In this work, we designed and synthesized one pair of acid cleavable polyfluorenes with defined chirality for handedness separation of s-SWCNTs from as-produced nanotubes. Each monomer contains a chiral center on the fluorene backbone in the 9-position, and the amino and carbonyl groups in the 2- and 7-positions maintain the head-to-tail regioselective polymerization resulting in polyimines with strictly all-(R) or all-(S) configuration. The obtained chiral polymers exhibit a strong recognition ability toward left- or right-handed s-SWCNTs from commercially available CoMoCAT SWCNTs with a sorting process requiring only bath sonication and centrifugation. Interestingly, the remaining polymer on each single nanotube, which helps to prevent aggregation, does not interfere with the circular dichroism signals from the nanotube at all. Therefore, we observed all four interband transition peaks (E11, E22, E33, E44) in the circular dichroism (CD) spectra of the still wrapped optically enriched left-handed and right-handed (6,5) SWCNTs in toluene. Binding energies obtained from molecular dynamics simulations were consistent with our experimental results and showed a significant preference for one specific handedness from each chiral polymer. Moreover, the imine bonds along the polymer chains enable the release of the nanotubes upon acid treatment. After s-SWNT separation, the polymer can be decomposed into monomers and be cleanly removed under mild acidic conditions, yielding dispersant-free handedness sorted s-SWNTs. The monomers can be almost quantitatively recovered to resynthesize the chiral polymer. This approach enables high selective isolation of polymer-free s-SWNT enantiomers for their further applications in carbon nanotube (CNT) devices.
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Frauhammer T, Gerhard L, Edelmann K, Lindner M, Valášek M, Mayor M, Wulfhekel W. Addressing a lattice of rotatable molecular dipoles with the electric field of an STM tip. Phys Chem Chem Phys 2021; 23:4874-4881. [PMID: 33616122 DOI: 10.1039/d0cp06146h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Functional molecular groups mounted on specific foot structures are ideal model systems to study intermolecular interactions, due to the possibility to separate the functionality and the adsorption mechanism. Here, we report on the rotational switching of a thioacetate group mounted on a tripodal tetraphenylmethane (TPM) derivative adsorbed in ordered islands on a Au(111) surface. Using low temperature scanning tunnelling microscopy, individual freestanding molecular groups of the lattice can be switched between two bistable orientations. The functional dependence of this rotational switching on the sample bias and tip-sample distance allows us to model the energy landscape of this molecular group as an electric dipole in the electric field of the tunnelling junction. As expected for the interaction of two dipoles, we found states of neighbouring molecules to be correlated.
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Mannancherry R, Šolomek T, Cavalli D, Malinčík J, Häussinger D, Prescimone A, Mayor M. Sulfone “Geländer” Helices: Revealing Unexpected Parameters Controlling the Enantiomerization Process. J Org Chem 2021; 86:5431-5442. [DOI: 10.1021/acs.joc.0c03016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Jucker L, Aeschi Y, Mayor M. Aqueous assembly of a (pseudo)rotaxane with a donor–π–acceptor axis formed by a Knoevenagel condensation. Org Chem Front 2021. [DOI: 10.1039/d1qo00643f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The incorporation of a linear D–π–A “push–pull” chromophore synthesized by a Knoevenagel condensation as axle of a rotaxane is reported.
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Zwick P, Hsu C, El Abbassi M, Fuhr O, Fenske D, Dulić D, van der Zant HSJ, Mayor M. Synthesis and Transport Studies of a Cofacial Porphyrin Cyclophane. J Org Chem 2020; 85:15072-15081. [PMID: 33166468 DOI: 10.1021/acs.joc.0c01957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Porphyrin cyclophane 1, consisting of two rigidly fixed but still movable cofacial porphyrins and exposing acetate-masked thiols in opposed directions of the macrocycle, is designed, synthesized, and characterized. The functional cyclophane 1, as pioneer of mechanosensitive 3D materials, forms stable single-molecule junctions in a mechanically controlled break-junction setup. Its reliable integration in a single-molecule junction is a fundamental prerequisite to explore the potential of these structures as mechanically triggered functional units and devices.
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Brandl T, Johannsen S, Häussinger D, Suryadevara N, Prescimone A, Bernhard S, Gruber M, Ruben M, Berndt R, Mayor M. Iron in a Cage: Fixation of a Fe(II)tpy 2 Complex by Fourfold Interlinking. Angew Chem Int Ed Engl 2020; 59:15947-15952. [PMID: 32412664 PMCID: PMC7540000 DOI: 10.1002/anie.202006340] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Indexed: 11/18/2022]
Abstract
The coordination sphere of the Fe(II) terpyridine complex 1 is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa-aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff-base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed-phase HPLC enables the isolation of the all-trans isomer of the Fe(II) terpyridine complex 1, which is fully characterized. While temperature independent low-spin states were recorded with superconducting quantum interference device (SQUID) measurements for both, the open precursor 8 and the interlinked complex 1, evidence of the increased rigidity of the ligand sphere in 1 was provided by proton T2 relaxation NMR experiments. The ligand sphere fixation in the macrocyclized complex 1 even reaches a level resisting substantial deformation upon deposition on an Au(111) surface, as demonstrated by its pristine form in a low temperature ultra-high vacuum scanning tunneling microscope experiment.
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Peters EH, Mayor M. Alkyne‐Monofunctionalized Gold Nanoparticles as Massive Molecular Building Blocks. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Brandl T, Johannsen S, Häussinger D, Suryadevara N, Prescimone A, Bernhard S, Gruber M, Ruben M, Berndt R, Mayor M. Iron in a Cage: Fixation of a Fe(II)tpy
2
Complex by Fourfold Interlinking. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Schätti J, Köhler V, Mayor M, Fein YY, Geyer P, Mairhofer L, Gerlich S, Arndt M. Matter-wave interference and deflection of tripeptides decorated with fluorinated alkyl chains. JOURNAL OF MASS SPECTROMETRY : JMS 2020; 55:e4514. [PMID: 32363659 PMCID: PMC7317408 DOI: 10.1002/jms.4514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 06/11/2023]
Abstract
Studies of neutral biomolecules in the gas phase allow for the study of molecular properties in the absence of solvent and charge effects, thus complementing spectroscopic and analytical methods in solution or in ion traps. Some properties, such as the static electronic susceptibility, are best accessed in experiments that act on the motion of the neutral molecules in an electric field. Here, we screen seven peptides for their thermal stability and electron impact ionizability. We identify two tripeptides as sufficiently volatile and thermostable to be evaporated and interfered in the long-baseline universal matter-wave interferometer. Monitoring the deflection of the interferometric molecular nanopattern in a tailored external electric field allows us to measure the static molecular susceptibility of Ala-Trp-Ala and Ala-Ala-Trp bearing fluorinated alkyl chains at C- and N-termini. The respective values are 4 π ε 0 × 330 ± 150 Å 3 and 4 π ε 0 × 270 ± 80 Å 3 .
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Palma Sanchez D, Haro A, Moreno MJ, Peñas E, Mayor M, Moreno M, Linares Ferrando LF. AB1290-HPR UTILITY OF FRAX IN THE RISK DETECTION OF FRACTURE IN SPONDYLOARTHRITIS. Ann Rheum Dis 2020. [DOI: 10.1136/annrheumdis-2020-eular.3839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background:Axial spondyloarthritis (SpAax) presents an increased risk of vertebral fracture not fully detected by Dual energy X-ray absorptiometry (DXA). The FRAX algorithms give the 10-year probability of hip fracture and of mayor osteoporotic fracture (clinical spine, forearm, hip or shoulder fracture), taking into account 11 clinical risk factors.Objectives:To analyze the suitability of FRAX to detect the risk of fracture in patients with SpAax. To assess whether the incorporation of SpAax as a clinical risk factor to conventional FRAX provides additional information.Methods:Cross-sectional study in which SpAax patients (ASAS criteria) were included. Clinical-demographic and related to the disease variables were collected. FRIDEX model for Spanish population was used to determine low, intermediate or high risk of mayor fracture by FRAX. These results were compared with those obtained by DXA and trabecular bone score (TBS). In the statistical analysis we used mean and standard deviation (SD) in quantitative variables and frequency in qualitative ones. To compare means among 3 groups, ANOVA test was used.Results:The characteristics of the patients are shown in Table 1. According to FRIDEX, no patient had high risk of fracture and 2.4% had intermediate risk. When SpAax was added as a risk factor, no patient had high risk of fracture and 6.1% presented intermediate risk. According to DXA, 7.3% had high risk of fracture and 41.3% intermediate risk. TBS detected high risk of fracture in 18.3% and intermediate risk also in 18.3% of patients.Table 1.Sociodemographic, clinical and related characteristics with the disease (BMD: bone mineral density, BMI: index of body mass)Gender (Male), n (%)61 (74.4)Age, mean ± SD49.48 ± 12.47BMI, mean ± SD27.13 ± 4.42Smoking, n (%)26 (31.7)Diabetes mellitus, n (%)9 (11)Osteoporotic fracture, n (%)1 (1.2)Disease duration (years), mean ± SD11.77 ± 10syndesmophytes, n (%)38 (46.3)ASDAS-PCR, mean ± SD2.55 ± 1.07Lumbar BMD (g / cm2), mean ± SD1.032 ± 0.180BMD femoral neck (g / cm2), mean ± SD0.816 ± 0.140Lumbar TBS, mean ± SD1.383 ± 0.133Conclusion:FRAX does not seem an adequate tool to detect the risk of fracture in patients with SpAax since it did not improve the results obtained by DXA meanwhile TBS did. The incorporation of SpAax as a clinical risk factor to conventional FRAX did not provide additional information in most casesDisclosure of Interests:None declared
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Prabodh A, Bauer D, Kubik S, Rebmann P, Klärner FG, Schrader T, Delarue Bizzini L, Mayor M, Biedermann F. Chirality sensing of terpenes, steroids, amino acids, peptides and drugs with acyclic cucurbit[n]urils and molecular tweezers. Chem Commun (Camb) 2020; 56:4652-4655. [PMID: 32253396 DOI: 10.1039/d0cc00707b] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Achiral chromophoric hosts, i.e. acyclic cucurbit[n]urils and molecular tweezers, were found to respond with characteristic Circular Dichroism (CD) spectra to the presence of micromolar concentrations of chiral hydrocarbons, terpenes, steroids, amino acids and their derivates, and drugs in water. In favourable cases, this allows for analyte identification or for reaction monitoring.
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Delarue Bizzini L, Bürgi T, Mayor M. The Enantiomers of Trinorbornane and Derivatives Thereof. Helv Chim Acta 2020. [DOI: 10.1002/hlca.202000019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Brandl T, Kerzig C, Le Pleux L, Prescimone A, Wenger OS, Mayor M. Improved Photostability of a Cu I Complex by Macrocyclization of the Phenanthroline Ligands. Chemistry 2020; 26:3119-3128. [PMID: 31794079 PMCID: PMC7079024 DOI: 10.1002/chem.201904754] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/30/2019] [Indexed: 11/12/2022]
Abstract
The development of molecular materials for conversion of solar energy into electricity and fuels is one of the most active research areas, in which the light absorber plays a key role. While copper(I)‐bis(diimine) complexes [CuI(L)2]+ are considered as potent substitutes for [RuII(bpy)3]2+, they exhibit limited structural integrity as ligand loss by substitution can occur. In this article, we present a new concept to stabilize copper bis(phenanthroline) complexes by macrocyclization of the ligands which are preorganized around the CuI ion. Using oxidative Hay acetylene homocoupling conditions, several CuI complexes with varying bridge length were prepared and analyzed. Absorption and emission properties are assessed; rewardingly, the envisioned approach was successful since the flexible 1,4‐butadiyl‐bridged complex does show enhanced MLCT absorption and emission, as well as improved photostability upon irradiation with a blue LED compared to a reference complex.
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