Dr. Michael Kathan
Profil
Forschungsthemen1
Nanoskopische Maschinen verzahnen chemische Strukturen (NanoMECHs)
Quelle ↗Förderer: DFG Nachwuchsgruppe Zeitraum: 10/2023 - 09/2026 Projektleitung: Dr. Michael Kathan
Mögliche Industrie-Partner10
Stand: 26.4.2026, 19:48:44 (Top-K=20, Min-Cosine=0.4)
- 23 Treffer60.4%
- Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)P60.4%
- Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)
- 39 Treffer60.4%
- Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)P60.4%
- EU: Bottom-Up Generation of atomicalLy Precise syntheTIc 2D MATerials for High Performance in Energy and Electronic Applications – A Multi-Site Innovative Training Action (ULTIMATE)P50.5%
- Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)
- 26 Treffer60.4%
- Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)P60.4%
- SIB-DE_Forschung - Sodium-Ion-Battery Deutschland (SIB:DE Initiative) - Eignung der Natrium-Ionen-Technologie für die europäische Energie- und MobilitätswendeP47.0%
- Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)
- 6 Treffer54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural SystemsP54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
- 6 Treffer54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural SystemsP54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
- 6 Treffer54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural SystemsP54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
- 6 Treffer54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural SystemsP54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
- 6 Treffer54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural SystemsP54.4%
- CUBES Circle – Closed Urban Modular Energy- and Resource-Efficient Agricultural Systems
- DYnamic control in hybrid plasmonic NAnopores: road to next generation multiplexed single MOlecule detectionP53.6%
- DYnamic control in hybrid plasmonic NAnopores: road to next generation multiplexed single MOlecule detection
- 6 Treffer52.8%
- Correlated Multielectron Dynamics in Intense Light Fields "CORINF" - HUMP52.8%
- Correlated Multielectron Dynamics in Intense Light Fields "CORINF" - HUM
Publikationen25
Top 25 nach Zitationen — Quelle: OpenAlex (BAAI/bge-m3 embedded für Matching).
Chemical Society Reviews · 306 Zitationen · DOI
In order to perform chemical work, molecular systems have to be operated away from thermodynamic equilibrium and therefore require the input of energy. Light is perhaps the most abundant and advantageous energy source that in combination with photoswitches allows for a reversible and hence continuous stimulation of a system. In this review, we illustrate how photoswitchable molecules can be used to escape the global thermodynamic minimum by populating metastable states, from which energy can be transferred and transformed in a controlled fashion. We emphasize the unique feature of photodynamic equilibria, in which population of the states is dictated by the excitation wavelength (and not primarily by temperature), thereby avoiding microscopic reversibility since the photoreaction involves an electronically excited state. Thus, photoswitchable molecular systems can remotely be controlled with high spatial and temporal resolution and in addition their action can be fueled by light.
Angewandte Chemie International Edition · 189 Zitationen · DOI
Various aldehyde-containing photoswitches have been developed whose reactivity toward amines can be controlled externally. A thermally stable bifunctional diarylethene, which in its ring-closed form exhibits imine formation accelerated by one order of magnitude, was used as a photoswitchable crosslinker and mixed with a commercially available amino-functionalized polysiloxane to yield a rubbery material with viscoelastic and self-healing properties that can be reversibly tuned by irradiation.
Nature Catalysis · 153 Zitationen · DOI
Journal of the American Chemical Society · 136 Zitationen · DOI
We present the synthesis and characterization of enantiomerically pure [6]helicene o-quinones (P)-(+)-1 and (M)-(-)-1 and their application to chiroptical switching and chiral recognition. (P)-(+)-1 and (M)-(-)-1 each show a reversible one-electron reduction process in their cyclic voltammogram, which leads to the formation of the semiquinone radical anions (P)-(+)-1(•-) and (M)-(-)-1(•-), respectively. Spectroelectrochemical ECD measurements give evidence of the reversible switching between the two redox states, which is associated with large differences of the Cotton effects [Δ(Δε)] in the UV and visible regions. The reduction of (±)-1 by lithium metal provides [Li(+){(±)-1(•-)}], which was studied by EPR and ENDOR spectroscopy to reveal substantial delocalization of the spin density over the helicene backbone. DFT calculations demonstrate that the lithium hyperfine coupling A((7)Li) in [Li(+){(±)-1(•-)}] is very sensitive to the position of the lithium cation. On the basis of this observation, chiral recognition by ENDOR spectroscopy was achieved by complexation of [Li(+){(P)-(+)-1(•-)}] and [Li(+){(M)-(-)-1(•-)}] with an enantiomerically pure phosphine oxide ligand.
Nature Chemistry · 124 Zitationen · DOI
Nature Nanotechnology · 86 Zitationen · DOI
Biological molecular machines enable chemical transformations, assembly, replication and motility, but most distinctively drive chemical systems out of-equilibrium to sustain life<sup>1,2</sup>. In such processes, nanometre-sized machines produce molecular energy carriers by driving endergonic equilibrium reactions. However, transforming the work performed by artificial nanomachines<sup>3-5</sup> into chemical energy remains highly challenging. Here, we report a light-fuelled small-molecule ratchet capable of driving a coupled chemical equilibrium energetically uphill. By bridging two imine<sup>6-9</sup> macrocycles with a molecular motor<sup>10,11</sup>, the machine forms crossings and consequently adopts several distinct topologies by either a thermal (temporary bond-dissociation) or photochemical (unidirectional rotation) pathway. While the former will relax the machine towards the global energetic minimum, the latter increases the number of crossings in the system above the equilibrium value. Our approach provides a blueprint for coupling continuous mechanical motion performed by a molecular machine with a chemical transformation to reach an out-of-equilibrium state.
Chemical Science · 50 Zitationen · DOI
The incorporation of molecular machines into the backbone of porous framework structures will facilitate nano actuation, enhanced molecular transport, and other out-of-equilibrium host-guest phenomena in well-defined 3D solid materials. In this work, we detail the synthesis of a diamine-based light-driven molecular motor and its incorporation into a series of imine-based polymers and covalent organic frameworks (COF). We study structural and dynamic properties of the molecular building blocks and derived self-assembled solids with a series of spectroscopic, diffraction, and theoretical methods. Using an acid-catalyzed synthesis approach, we are able to obtain the first crystalline 2D COF with stacked hexagonal layers that contains 20 mol% molecular motors. The COF features a specific pore volume and surface area of up to 0.45 cm<sup>3</sup> g<sup>-1</sup> and 604 m<sup>2</sup> g<sup>-1</sup>, respectively. Given the molecular structure and bulkiness of the diamine motor, we study the supramolecular assembly of the COF layers and detail stacking disorders between adjacent layers. We finally probe the motor dynamics with <i>in situ</i> spectroscopic techniques revealing current limitations in the analysis of these new materials and derive important analysis and design criteria as well as synthetic access to new generations of motorized porous framework materials.
Angewandte Chemie International Edition · 48 Zitationen · DOI
In a chemical equilibrium, the formation of high-energy species-in a closed system-is inefficient due to microscopic reversibility. Here, we demonstrate how this restriction can be circumvented by coupling a dynamic equilibrium to a light-induced E/Z isomerization of an azobenzene imine cage. The stable E-cage resists intermolecular imine exchange reactions that would "open" it. Upon switching, the strained Z-cage isomers undergo imine exchange spontaneously, thus opening the cage. Subsequent isomerization of the Z-open compounds yields a high-energy, kinetically trapped E-open species, which cannot be efficiently obtained from the initial E-cage, thus shifting an imine equilibrium energetically uphill in a closed system. Upon heating, the nucleophile is displaced back into solution and an opening/closing cycle is completed by regenerating the stable all-E-cage. Using this principle, a light-induced cage-to-cage transformation is performed by the addition of a ditopic aldehyde.
Chemical Communications · 41 Zitationen · DOI
A class of novel corannulene-derived ferrocene donor-acceptor systems has been synthesized by straight-forward Negishi-type coupling of iodocorannulene. Their solid state structures have been studied crystallographically and found to exhibit unique inter- and intramolecular slipped stacking interactions.
Angewandte Chemie International Edition · 28 Zitationen · DOI
The transfer of stereoinformation is at the heart of asymmetric reactions. By incorporating the natural monoterpene l-menthone into the backbone of a diarylethene, we achieved efficient chirality transfer upon photocyclization, resulting in the preferred formation of one major closed isomer in a diastereomeric ratio (d.r.) of 85:15. More significantly, we were able to completely reverse the diastereomeric outcome of the ring closure simply by altering the chemical environment or the irradiation conditions. As a result, we could selectively accumulate the less favored minor closed isomer, with remarkable d.r. values of >99:1 and 74:26, respectively. Computations revealed that a stability inversion after photocyclization is the basis for the observed unprecedented control over diastereoselectivity.
Angewandte Chemie · 28 Zitationen · DOI
Abstract Es wurden mehrere aldehydsubstituierte Photoschalter entwickelt, deren Reaktivität gegenüber Aminen ferngesteuert werden kann. Ein thermisch stabiles, difunktionelles Diarylethen, das in seiner ringgeschlossenen Form eine um den Faktor zehn erhöhte Reaktivität gegenüber Aminen aufweist, wurde als photoschaltbarer Vernetzer für ein kommerziell erhältliches, aminofunktionalisiertes Polysiloxan eingesetzt. Die Selbstheilungsgeschwindigkeit und viskoelastischen Eigenschaften dieses gummiartigen Materials können somit reversibel mit Licht moduliert werden.
Angewandte Chemie International Edition · 22 Zitationen · DOI
In artificial small-molecule machines, molecular motors can be used to perform work on coupled systems by applying a mechanical load-such as strain-that allows for energy transduction. Here, we report how ring strain influences the rotation of a rotary molecular motor. Bridging the two halves of the motor with alkyl tethers of varying sizes yields macrocycles that constrain the motor's movement. Increasing the ring size by two methylene increments increases the mobility of the motor stepwise and allows for fine-tuning of strain in the system. Small macrocycles (8-14 methylene units) only undergo a photochemical E/Z isomerization. Larger macrocycles (16-22 methylene units) can perform a full rotational cycle, but thermal helix inversion is strongly dependent on the ring size. This study provides systematic and quantitative insight into the behavior of molecular motors under a mechanical load, paving the way for the development of complex coupled nanomachinery.
Science · 19 Zitationen · DOI
Precise mechanical manipulation of molecules is inherently difficult owing to random thermal motion. Although directed movement on the molecular scale has been achieved, using it to impose specific-especially energetically disfavored-shapes on molecules and construct mechanically interlocked structures remains a fundamental challenge. In this study, we report the synthesis of a catenane enabled by a molecular motor that winds molecular strands into discrete entangled structures, each defined by a specific number of mechanical crossings. Light energy drives unidirectional motor rotation, enabling path-dependent control over a sequence of thermodynamically disfavored yet mechanically distinct and kinetically stable winding states, which are covalently captured and subsequently released to yield a catenane. This machine-directed approach offers a general proof-of-concept strategy for the template-free construction of mechanically interlocked molecules.
European Journal of Inorganic Chemistry · 16 Zitationen · DOI
Abstract The syntheses and properties of corannulenes bearing different numbers and types of ferrocenyl groups are described. Six different monoferrocenylated corannulenes were synthesized, and the crystal structure of 1‐corannulenyl‐1′‐(ferrocenyl)benzene was elucidated by single‐crystal X‐ray analysis. Further, diferrocenylated corannulenes bearing methyl or trifluoromethyl groups are reported. Buckybowls with four and five ferrocenyl substituents were synthesized from tetrabromocorannulene and the symmetrical pentachlorocorannulene. The molecular structure and nutshell‐like crystal packing of a tetraferrocenylated corannulene was determined by single‐crystal X‐ray analysis. Additionally, all compounds presented herein were subjected to electrochemical and optical measurements in solution.
Journal of Polymer Science Part A Polymer Chemistry · 11 Zitationen · DOI
ABSTRACT Here, we describe a “smart” polymeric material, which is able to readily detect and discriminate amine vapors. The dynamic imine‐based network can be conveniently prepared by mixing a commercially available, amino‐functionalized polysiloxane with small amounts of a diarylethene dialdehyde. The photoswitchable crosslinker allows for reversible imprinting of custom‐designed patterns on the polymer surface with (sun)light and thus enables noninvasive information storage in the material, which before, during, and after amine exposure can readily be decoded with commonly used smartphone apps. This feature along with the self‐healing nature of the dynamic polymer, an easy recycling and manufacturing procedure, and the overall low cost and toxicity render this material advantageous to develop low‐cost and practical amine sensing devices for the broad public. © 2019 The Authors. Journal of Polymer Science Part A: Polymer Chemistry published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57 , 2378–2382
Angewandte Chemie · 9 Zitationen · DOI
Abstract In artificial small‐molecule machines, molecular motors can be used to perform work on coupled systems by applying a mechanical load—such as strain—that allows for energy transduction. Here, we report how ring strain influences the rotation of a rotary molecular motor. Bridging the two halves of the motor with alkyl tethers of varying sizes yields macrocycles that constrain the motor's movement. Increasing the ring size by two methylene increments increases the mobility of the motor stepwise and allows for fine‐tuning of strain in the system. Small macrocycles (8–14 methylene units) only undergo a photochemical E / Z isomerization. Larger macrocycles (16–22 methylene units) can perform a full rotational cycle, but thermal helix inversion is strongly dependent on the ring size. This study provides systematic and quantitative insight into the behavior of molecular motors under a mechanical load, paving the way for the development of complex coupled nanomachinery.
Angewandte Chemie · 6 Zitationen · DOI
Abstract Der Transfer von Stereoinformation ist das Herzstück asymmetrischer Reaktionen. Durch die Integration des natürlichen Monoterpens l ‐Menthon in das Rückgrat eines Diarylethens konnte ein effizienter Chiralitätstransfer bei der Photocyclisierung erreicht werden, was zur bevorzugten Bildung eines geschlossenen Hauptisomers mit einem Diastereomerenverhältnis (d.r.) von 85:15 führte. Noch stärker hervorzuheben ist allerdings, dass die Diastereoselektivität des Ringschlusses vollständig umgekehrt werden kann, indem die chemische Umgebung oder die Bestrahlungsbedingungen verändert werden. Infolgedessen konnte selektiv das weniger favorisierte geschlossene Isomer mit bemerkenswerten d.r.‐Werten von >99:1 bzw. 74:26 akkumuliert werden. Berechnungen zeigen, dass eine Stabilitätsinversion nach der Photocyclisierung die Grundlage für die beobachtete beispiellose Kontrolle der Diastereoselektivität ist.
3 Zitationen · DOI
This chapter outlines how photoswitchable molecules can be used to perturb thermal equilibria and how this unique feature is applied in molecular, microscopic, and even macroscopic systems. It explains the fundamentals of photodynamic equilibria and introduces the most prominent classes of photoswitchable molecules. The chapter illustrates how photoswitches can be used to drive chemical systems with light. The photoswitching event can enhance or reduce the reactivity in a dynamic covalent reaction. Chemical transport constitutes an essential part of chemical work in living systems since reactants and products have to actively be pumped in and out of the cell, against an existing gradient. Self-assembly constitutes a very powerful mechanism to obtain elaborate functional structures and amplify the properties of the individual components. Nature developed an ingenious method to drive thermodynamically disfavored reactions: photosynthesis. The chapter highlights functional molecular systems, in which the incorporation of photoswitchable units enables light to be used as their external power supply.
Angewandte Chemie · 2 Zitationen · DOI
Abstract In a chemical equilibrium, the formation of high‐energy species—in a closed system—is inefficient due to microscopic reversibility. Here, we demonstrate how this restriction can be circumvented by coupling a dynamic equilibrium to a light‐induced E / Z isomerization of an azobenzene imine cage. The stable E ‐cage resists intermolecular imine exchange reactions that would “open” it. Upon switching, the strained Z ‐cage isomers undergo imine exchange spontaneously, thus opening the cage. Subsequent isomerization of the Z ‐open compounds yields a high‐energy, kinetically trapped E ‐open species, which cannot be efficiently obtained from the initial E ‐cage, thus shifting an imine equilibrium energetically uphill in a closed system. Upon heating, the nucleophile is displaced back into solution and an opening/closing cycle is completed by regenerating the stable all‐ E ‐cage. Using this principle, a light‐induced cage‐to‐cage transformation is performed by the addition of a ditopic aldehyde.
ChemRxiv · 2 Zitationen · DOI
The incorporation of molecular machines into the backbone of porous framework structures will facilitate nano actuation, enhanced molecular transport, and other out-of-equilibrium host-guest phenomena in well-defined 3D solid materials. In this work, we detail the synthesis of a diamine-based light-driven molecular motor and its incorporation into a series of imine-based polymers and covalent organic frameworks (COF). We study structural and dynamic properties of the molecular building blocks and derived self-assembled solids with a series of spectroscopic, diffraction, and theoretical methods. Using an acid-catalyzed synthesis approach, we are able to obtain the first crystalline 2D COF with stacked hexagonal layers that contains 20 mol-% molecular motors. The COF features a specific pore volume and surface area of up to 0.45 cm3 g−1 and 604 m2 g−1, respectively. Given the molecular structure and bulkiness of the diamine motor, we study the supramolecular assembly of the COF layers and detail stacking disorders between adjacent layers. We finally probe the motor dynamics with in situ spectroscopic techniques revealing current limitations in the analysis of the these new materials and derive important analysis and design criteria as well as synthetic access to new generations of motorized porous framework materials.
Angewandte Chemie · 1 Zitationen · DOI
Kurzzusammenfassung Präorganisation durch Assemblierungs‐ oder Templatstrategien wird häufig in der Synthese von Rotaxanen eingesetzt. Während diese Ansätze die Herstellung komplexer, ineinander verzahnter Moleküle ermöglicht haben, sind sie oft durch strenge strukturelle Anforderungen an Templat und Ausgangsstoffe limitirt. Wir berichten hier über eine molekulare Maschine, die die Synthese eines Rotaxans durch aktives mechanisches Formen der Ausgangsbausteine steuert. Die lichtinduzierte Rotation eines molekularen Motors wickelt dabei gezielt einen molekularen Strang um eine Achse und erzeugt dabei diskrete, thermodynamisch ungünstige Kreuzungspunkte zwischen beiden Komponenten. Durch kovalente Fixierung werden diese kinetisch stabilen Verschlingungen chemisch konserviert, wodurch der gewundene Strang in einen Makrozyklus überführt wird. Dieser wird anschließend abgelöst und dabei mechanisch auf der Achse aufgefädelt, was zur Bildung eines Rotaxans führt. Diese maschinengesteuerte Strategie eröffnet einen neuartigen Zugang zur Synthese von Rotaxanen durch aktives mechanisches Formen molekularer Bausteine und ermöglicht den Aufbau ineinander verzahnter Architekturen, die jenseits der Möglichkeiten herkömmlicher Assemblierungs‐ und Templatmethoden liegen.
Angewandte Chemie International Edition · 1 Zitationen · DOI
Preorganization by assembly or templating strategies is frequently used in the synthesis of rotaxanes. While these approaches have led to complex interlocked molecules, they are often limited by strict compositional requirements of templates and starting materials. Here, we use a molecular machine to direct the synthesis of a rotaxane by active shaping of starting materials through mechanical winding. Light induced rotation of a molecular motor actively winds a molecular strand around an axle, forming discrete, thermodynamically disfavored crossings between these two parts. Covalent capture preserves the kinetically stable entanglements, transforming the strand into a macrocycle that is subsequently released and mechanically trapped on the axle, yielding a rotaxane. Our machine-directed strategy pioneers a new way of synthesizing rotaxanes by active mechanical shaping of molecular building blocks, enabling access to interlocked architectures beyond the reach of traditional assembly and templating approaches.
ChemRxiv · DOI
Direct measurements of molecular motion during chemical reactions are essential to understand how molecular machines perform work. In most systems, however, the reaction rate is dictated by the probability of reaching the transition state, thereby masking the underlying molecular motions. Here, we study the dynamics of rotation around the central double bond of an artificial light-driven molecular motor by femtosecond transient absorption and fluorescence spectroscopy. We observe a first rotation step of 28° which occurs synchronously across the motor ensemble and without an activation barrier, such that the measurements are representative of molecular dynamics. We can thus estimate the rotation speed and the relative importance of inertia, friction and strain, and propose a simplified nanomechanical model for the molecular motor. The results promise a new window of investigation into work at the nanoscale, and provide tools to analyze the mechanics of molecular machines, both synthetic or biological.
The Cambridge Structural Database · DOI
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
edoc Publication server (Humboldt University of Berlin) · DOI
Preorganization by assembly or templating strategies is frequently used in the synthesis of rotaxanes. While these approaches have led to complex interlocked molecules, they are often limited by strict compositional requirements of templates and starting materials. Here, we use a molecular machine to direct the synthesis of a rotaxane by active shaping of starting materials through mechanical winding. Light induced rotation of a molecular motor actively winds a molecular strand around an axle, forming discrete, thermodynamically disfavored crossings between these two parts. Covalent capture preserves the kinetically stable entanglements, transforming the strand into a macrocycle that is subsequently released and mechanically trapped on the axle, yielding a rotaxane. Our machine‐directed strategy pioneers a new way of synthesizing rotaxanes by active mechanical shaping of molecular building blocks, enabling access to interlocked architectures beyond the reach of traditional assembly and templating approaches.
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Stammdaten
Identität, Organisation und Kontakt aus HU-FIS.
- Name
- Dr. Michael Kathan
- Titel
- Dr.
- Fakultät
- Mathematisch-Naturwissenschaftliche Fakultät
- Institut
- Institut für Chemie
- Arbeitsgruppe
- NWG Molekulare Maschinen
- Telefon
- +49 30 2093-7237
- HU-FIS-Profil
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- 26.4.2026, 01:07:03