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1,159 results on '"Nitschke, Jonathan R."'

2. Supramolecular self-assembly as a tool to preserve electronic purity of perylene diimide chromophores

Author

Heckelmann, Ina, Lu, Zifei, Prentice, Joseph C. A., Auras, Florian, Ronson, Tanya K., Friend, Richard H., Nitschke, Jonathan R., and Feldmann, Sascha

Subjects
Physics - Chemical Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

Small molecule organic semiconductors hold great promise for efficient, printable, and flexible optoelectronic applications like solar cells and displays. However, strong excited-state quenching due to uncontrolled aggregation currently limits their performance and employability in devices. Here, we report on the self-assembly of a supramolecular pseudo-cube formed from six modified tetradentate perylene diimides (PDIs). The rigid, shape-persistent cage sets the distance and orientation of the PDI chromophores and suppresses intramolecular rotations and vibrations, leading to non-aggregated, monomer-like electronic properties in solution as well as in the solid state, in contrast to the fast fluorescence quenching in the free ligand. The stabilized excited state and electronic purity of the cage enable the observation of delayed fluorescence due to a bright excited multimer state, which acts as an excited state reservoir, due to a rare case of benign inter-chromophore interactions in the cage. Our results suggest that not only the photophysical properties of the subcomponents but the geometric structure is crucial for the overall optoelectronic properties of supramolecular systems. We show that self-assembly provides a powerful tool for retaining and controlling the electronic properties of well-studied chromophores, providing a route to bring molecular electronics applications in reach.

Published
2022

9. Metal Ions Trigger the Gelation of Cysteine‐Containing Peptide‐Appended Coordination Cages.

Author

Li, Meng, Zhu, Huangtianzhi, Adorinni, Simone, Xue, Weichao, Heard, Andrew, Garcia, Ana M., Kralj, Slavko, Nitschke, Jonathan R., and Marchesan, Silvia

Subjects
MODULAR design, SULFHYDRYL group, PEPTIDES, METAL ions, GELATION
Abstract

We report a series of coordination cages that incorporate peptide chains at their vertices, prepared through subcomponent self‐assembly. Three distinct heterochiral tripeptide subcomponents were incorporated, each exhibiting an L−D−L stereoconfiguration. Through this approach, we prepared and characterized three tetrahedral metal‐peptide cages that incorporate thiol and methylthio groups. The gelation of these cages was probed through the binding of additional metal ions, with the metal‐peptide cages acting as junctions, owing to the presence of sulfur atoms on the peripheral peptides. Gels were obtained with cages bearing cysteine at the C‐terminus. Our strategy for developing functional metal‐coordinated supramolecular gels with a modular design may result in the development of materials useful for chemical separations or drug delivery. [ABSTRACT FROM AUTHOR]

Published
2024
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21. Quantifying the Effect of Guest Binding on Host Environment

Author

Ryan, Hugh P., primary, Fishman, Zachary S., additional, Pawlik, Jacob T., additional, Grommet, Angela, additional, Musial, Malgorzata, additional, Rizzuto, Felix, additional, Booth, James C., additional, Long, Christian J., additional, Schwarz, Kathleen, additional, Orloff, Nathan D., additional, Nitschke, Jonathan R., additional, and Stelson, Angela C., additional

Published
2023
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24. An antiaromatic-walled nanospace

Author

Yamashina, Masahiro, Tanaka, Yuya, Lavendomme, Roy, Ronson, Tanya K., Pittelkow, Michael, and Nitschke, Jonathan R.

Subjects
Nanoparticles -- Design and construction -- Chemical properties, Self-organizing systems -- Design and construction -- Chemical properties, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Over the past few decades, several molecular cages, hosts and nanoporous materials enclosing nanometre-sized cavities have been reported.sup.1-5, including coordination-driven nanocages.sup.6. Such nanocages have found widespread use in molecular recognition, separation, stabilization and the promotion of unusual chemical reactions, among other applications.sup.3-10. Most of the reported nanospaces within molecular hosts are confined by aromatic walls, the properties of which help to determine the host-guest behaviour. However, cages with nanospaces surrounded by antiaromatic walls have not yet been developed, owing to the instability of antiaromatic compounds; as such, the effect of antiaromatic walls on the properties of nanospaces remains unknown. Here we demonstrate the construction of an antiaromatic-walled nanospace within a self-assembled cage composed of four metal ions with six identical antiaromatic walls. Calculations indicate that the magnetic effects of the antiaromatic moieties surrounding this nanospace reinforce each other. This prediction is confirmed by .sup.1H nuclear magnetic resonance (NMR) signals of bound guest molecules, which are observed at chemical shift values of up to 24 parts per million (ppm), owing to the combined antiaromatic deshielding effect of the surrounding rings. This value, shifted 15 ppm from that of the free guest, is the largest .sup.1H NMR chemical shift displacement resulting from an antiaromatic environment observed so far. This cage may thus be considered as a type of NMR shift reagent, moving guest signals well beyond the usual NMR frequency range and opening the way to further probing the effects of an antiaromatic environment on a nanospace. The construction of a self-assembled nanocage composed of four metal ions and six antiaromatic walls is demonstrated, and the effect of antiaromaticity on the host-guest properties is investigated., Author(s): Masahiro Yamashina [sup.1] [sup.4] , Yuya Tanaka [sup.2] , Roy Lavendomme [sup.1] , Tanya K. Ronson [sup.1] , Michael Pittelkow [sup.3] , Jonathan R. Nitschke [sup.1] Author Affiliations: (1) [...]

Published
2019
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25. Supramolecular Self-Assembly as a Tool To Preserve the Electronic Purity of Perylene Diimide Chromophores

Author

Heckelmann, Ina, Lu, Zifei, Prentice, Joseph CA, Auras, Florian, Ronson, Tanya K, Friend, Richard H, Nitschke, Jonathan R, Feldmann, Sascha, Lu, Zifei [0000-0002-6710-2808], Prentice, Joseph CA [0000-0001-9641-4643], Auras, Florian [0000-0003-1709-4384], Ronson, Tanya K [0000-0002-6917-3685], Friend, Richard H [0000-0001-6565-6308], Nitschke, Jonathan R [0000-0002-4060-5122], Feldmann, Sascha [0000-0002-6583-5354], and Apollo - University of Cambridge Repository

Subjects
3403 Macromolecular and Materials Chemistry, Photophysics, 34 Chemical Sciences, Metal-Organic Cage, Molecular Electronics, Supramolecular Chemistry, 3405 Organic Chemistry, General Chemistry, General Medicine, Catalysis
Abstract

Organic semiconductors are promising for efficient, printable optoelectronics. However, strong excited-state quenching due to uncontrolled aggregation limits their use in devices. We report on the self-assembly of a supramolecular pseudo-cube formed from six perylene diimides (PDIs). The rigid, shape-persistent cage sets the distance and orientation of the PDIs and suppresses intramolecular rotations and vibrations, leading to non-aggregated, monomer-like properties in solution and the solid state, in contrast to the fast fluorescence quenching in the free ligand. The stabilized excited state and electronic purity in the cage enables the observation of delayed fluorescence due to a bright excited multimer, acting as excited-state reservoir in a rare case of benign inter-chromophore interactions in the cage. We show that self-assembly provides a powerful tool for retaining and controlling the electronic properties of chromophores, and to bring molecular electronics devices within reach., Angewandte Chemie. International Edition, 62 (12), ISSN:1433-7851, ISSN:1521-3773, ISSN:0570-0833

Published
2023

26. Subtle Stereochemical Effects Influence Binding and Purification Abilities of an FeII4L4 Cage

Author

Xue, Weichao, Pesce, Luca, Bellamkonda, Adinarayana, Ronson, Tanya K, Wu, Kai, Zhang, Dawei, Vanthuyne, Nicolas, Brotin, Thierry, Martinez, Alexandre, Pavan, Giovanni M, Nitschke, Jonathan R, Xue, Weichao [0000-0002-8376-9485], Pesce, Luca [0000-0001-6364-9577], Ronson, Tanya K [0000-0002-6917-3685], Wu, Kai [0000-0001-6336-7836], Zhang, Dawei [0000-0002-0898-9795], Vanthuyne, Nicolas [0000-0003-2598-7940], Brotin, Thierry [0000-0001-9746-4706], Martinez, Alexandre [0000-0002-6745-5734], Pavan, Giovanni M [0000-0002-3473-8471], Nitschke, Jonathan R [0000-0002-4060-5122], and Apollo - University of Cambridge Repository

Subjects
3402 Inorganic Chemistry, 3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, Article
Abstract

Funder: Deutsche Forschungsgemeinschaft, A tetrahedral FeII4L4 cage assembled from the coordination of triangular chiral, face-capping ligands to iron(II). This cage exists as two diastereomers in solution, which differ in the stereochemistry of their metal vertices, but share the same point chirality of the ligand. The equilibrium between these cage diastereomers was subtly perturbed by guest binding. This perturbation from equilibrium correlated with the size and shape fit of the guest within the host; insight as to the interplay between stereochemistry and fit was provided by atomistic well-tempered metadynamics simulations. The understanding thus gained as to the stereochemical impact on guest binding enabled the design of a straightforward process for the resolution of the enantiomers of a racemic guest.

Published
2023
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27. Tetramine Aspect Ratio and Flexibility Determine Framework Symmetry for Zn8 L6 Self-Assembled Structures

Author

Davies, Jack A, Tarzia, Andrew, Ronson, Tanya K, Auras, Florian, Jelfs, Kim E, Nitschke, Jonathan R, Davies, Jack A [0000-0003-4625-7701], Tarzia, Andrew [0000-0001-8797-8666], Ronson, Tanya K [0000-0002-6917-3685], Auras, Florian [0000-0003-1709-4384], Jelfs, Kim E [0000-0001-7683-7630], Nitschke, Jonathan R [0000-0002-4060-5122], and Apollo - University of Cambridge Repository

Subjects
Self-Assembly, Stereochemistry, Metal-Organic Cages, Supramolecular Chemistry
Abstract

We derive design principles for the assembly of rectangular tetramines into Zn8 L6 pseudo-cubic coordination cages. Because of the rectangular, as opposed to square, geometry of the ligand panels, and the possibility of either Δ or Λ handedness of each metal center at the eight corners of the pseudo-cube, many different cage diastereomers are possible. Each of the six tetra-aniline subcomponents investigated in this work assembled with zinc(II) and 2-formylpyridine in acetonitrile into a single Zn8 L6 pseudo-cube diastereomer, however. Each product corresponded to one of four diastereomeric configurations, with T, Th , S6 or D3 symmetry. The preferred diastereomer for a given tetra-aniline subcomponent was shown to be dependent on its aspect ratio and conformational flexibility. Analysis of computationally modeled individual faces or whole pseudo-cubes provided insight as to why the observed diastereomers were favored.

Published
2023
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35. Host Spin-Crossover Thermodynamics Indicate Guest Fit

Author

Zheng, Jieyu, Von Krbek, Larissa KS, Ronson, Tanya K, Nitschke, Jonathan R, Zheng, Jieyu [0000-0002-6658-0672], von Krbek, Larissa KS [0000-0002-4278-5235], Ronson, Tanya K [0000-0002-6917-3685], Nitschke, Jonathan R [0000-0002-4060-5122], and Apollo - University of Cambridge Repository

Subjects
Host-Guest Chemistry, Spin Crossover, Metal-Organic Cages
Abstract

Funder: Cambridge Trust; Id: http://dx.doi.org/10.13039/501100003343, Funder: Newnham College, University of Cambridge; Id: http://dx.doi.org/10.13039/501100000663, Spin-crossover (SCO) metal-organic cages capable of switching between high-spin and low-spin states have the potential to be used as magnetic sensors and switches. Variation of the donor strength of heterocyclic aldehyde subcomponents in imine-based ligands can tune the ligand field for a FeII center, which results in both homoleptic and heteroleptic cages with diverse SCO behaviors. The tetrahedral SCO cage built from 1-methyl-1H-imidazole-2-carbaldehyde is capable of encapsulating various guests, which stabilize different cage spin states depending on guest size. Conversely, the SCO tetrahedron exhibits different affinities for guests in different spin states, which is inferred to result from subtle structural differences of the cavity caused by the change in metal center spin state. Examination of SCO thermodynamics across a series of host-guest complexes enabled sensitive probing of guest fit to the host cavity, providing information complementary to binding-constant determination.

Published
2022
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48. Stereocontrolled Self-Assembly of a Helicate-Bridged CuI12L4Cage That Emits Circularly Polarized Light

Author

Zhu, Huangtianzhi, Pesce, Luca, Chowdhury, Rituparno, Xue, Weichao, Wu, Kai, Ronson, Tanya K., Friend, Richard H., Pavan, Giovanni M., and Nitschke, Jonathan R.

Abstract

Control over the stereochemistry of metal–organic cages can give rise to useful functions that are entwined with chirality, such as stereoselective guest binding and chiroptical applications. Here, we report a chiral CuI12L4pseudo-octahedral cage that self-assembled from condensation of triaminotriptycene, aminoquinaldine, and diformylpyridine subcomponents around CuItemplates. The corners of this cage consist of six head-to-tail dicopper(I) helicates whose helical chirality can be controlled by the addition of enantiopure 1,1′-bi-2-naphthol (BINOL) during the assembly process. Chiroptical and nuclear magnetic resonance (NMR) studies elucidated the process and mechanism of stereochemical information transfer from BINOL to the cage during the assembly process. Initially formed CuI(BINOL)2thus underwent stereoselective ligand exchange during the formation of the chiral helicate corners of the cage, which determined the overall cage stereochemistry. The resulting dicopper(I) helicate corners of the cage were also shown to generate circularly polarized luminescence.

Published
2024
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49. Steric and Geometrical Frustration Generate Two Higher-Order CuI12L8Assemblies from a Triaminotriptycene Subcomponent

Author

Zhu, Huangtianzhi, Ronson, Tanya K., Wu, Kai, and Nitschke, Jonathan R.

Abstract

The use of copper(I) in metal–organic assemblies leads readily to the formation of simple grids and helicates, whereas higher-order structures require complex ligand designs. Here, we report the clean and selective syntheses of two complex and structurally distinct CuI12L8frameworks, 1and 2, which assemble from the same simple triaminotriptycene subcomponent and a formylpyridine around the CuItemplates. Both represent new structure types. In T-symmetric 1, the copper(I) centers describe a pair of octahedra with a common center but whose vertices are offset from each other, whereas in D3-symmetric 2, the metal ions form a distorted hexagonal prism. The syntheses of these architectures illustrate how more intricate CuI-based complexes can be prepared via subcomponent self-assembly than has been possible to date through consideration of the interplay between the subcomponent geometry and solvent and electronic effects.

Published
2024
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