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5. Tetrazole and Oxadiazole Derivatives as Thermally Activated Delayed Fluorescence Emitters.

Author

Leonhardt, Céline, Mauri, Anna, Garin, Idoia, Rosemann, Nils W., Wenzel, Wolfgang, Lemmer, Uli, Kozlowska, Mariana, and Bräse, Stefan

Subjects
DELAYED fluorescence, CHARGE transfer, QUANTUM efficiency, DENSITY functional theory, BAND gaps, ORGANIC light emitting diodes
Abstract

Organic light‐emitting diodes (OLEDs) are promising lighting solutions for sustainability and energy efficiency. Incorporating thermally activated delayed fluorescence (TADF) molecules enables OLEDs to achieve internal quantum efficiency (IQE), in principle, up to 100 %; therefore, new classes of promising TADF emitters and modifications of existing ones are sought after. This study explores the TADF emission properties of six designed TADF emitters, examining their photophysical responses using experimental and theoretical methods. The design strategy involves creating six distinct types of a donor‐acceptor (D−A) system, where tert‐butylcarbazoles are used as donors, while the acceptor component incorporates three different functional groups: nitrile, tetrazole and oxadiazole, with varying electron‐withdrawing character. Additionally, the donor‐acceptor distance is adjusted using a phenylene spacer, and its influence on TADF functionality is examined. The clear dependency of an additional spacer, inhibiting TADF, could be revealed. Emitters with a direct donor‐acceptor connection are demonstrated to exhibit TADF moderate emissive behavior. The analysis emphasizes the impact of charge transfer, singlet‐triplet energy gaps (ΔEST), and other microscopic parameters on photophysical rates, permitting TADF. Among the emitters, TCz‐CN shows optimal performance as a blue‐green emitter with an 88 % photoluminescence quantum yield (PLQY) and fast rate of reversible intersystem crossing of 2×106 s−1 and 1×107 s−1, obtained from time‐resolved photoluminescence (TRPL) experiment in PMMA matrix and quantum mechanical calculations, respectively. This comprehensive exploration identifies molecular bases of superior TADF emitters and provides insights for future designs, advancing the optimization of TADF properties in OLEDs. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Enantiomer Differentiation by Interaction-Specific Prediction of Residual Dipolar Couplings in Spherical-like Molecules

Author

Elsing, David, Luy, Burkhard, and Kozlowska, Mariana

Abstract

Residual Dipolar Couplings (RDCs) are averaged dipolar couplings between nuclear spins of atoms in a molecule that can be measured by nuclear magnetic resonance (NMR) spectroscopy upon partial alignment by a chiral alignment medium. The estimation of differences in alignment of enantiomers may, in principle, enable the determination of absolute configuration. Here, we use molecular dynamics (MD) simulations to mimic the alignment of chiral molecules (i.e., isopinocampheol, quinuclidin-3-ol, borneol, and camphor) to the chiral poly-γ-benzyl-L-glutamate (PBLG) polymer to predict RDCs in silicoand compare calculated and experimentally measured residual dipolar couplings for the four enantiomeric pairs. The aim is to validate the computational scheme for the prediction of RDCs in chiral molecules and understand the interaction leading to the alignment in more detail. We determine the indispensable importance of hydrogen bonds between a chiral molecule and the alignment medium on the overall quality of the simulated alignment and interaction poses toward high agreement with experiments. A good correlation with experimental data is found for camphor and isopinocampheol, while the correlation for quinuclidin-3-ol and borneol is lower. We attribute this observation to the high difficulty of the RDC prediction for rather almost spherical molecules. The study reveals that the prediction of alignment with small enantiomeric differences is possible with an MD-based approach; however, extended simulation times (e.g., 50–100 μs) are required to sufficiently reduce the statistical uncertainty. This may be further used for the determination of the relative, as well as absolute, configuration of chiral molecules.

Published
2024
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10. Disulfide‐Bridged Dynamic Covalent Triazine Polymer Thin Films by Interface Polymerization: High Refractive Index with Excellent Optical Transparency.

Author

Begum, Salma, Kutonova, Ksenia, Mauri, Anna, Koenig, Meike, Chan, Ka Chun, Sprau, Christian, Dolle, Christian, Trouillet, Vanessa, Hassan, Zahid, Leonhard, Tobias, Heißler, Stefan, Eggeler, Yolita M., Wenzel, Wolfgang, Kozlowska, Mariana, and Bräse, Stefan

Subjects
POLYMER films, REFRACTIVE index, THIN films, POLYMERS, MOLECULAR structure, TRIAZINES, POLYMERIZATION, DISULFIDES
Abstract

Exploring innovative strategies for molecular structuring of dynamic materials that combine self‐correcting intrinsic reversibility with the robustness of covalent bonds, has been a long‐standing objective from applications perspective in fields ranging from molecular engineering to nanotechnology and interfacial science. To establish dynamic covalent chemistry approaches combined with interfacial polymerization, herein, a distinct synthetic approach is reported to develop disulfide‐bridged 2D polymeric C3N3S3 triazine thin‐films by interfacial thiol‐disulfide dynamic exchange process crosslinking tritopic planar 1,3,5‐triazine‐2,4,6‐trithiol molecular tectons via intermolecular disulfide formation in the presence of I2 vapors at the air/water interface under redox condition. The resulting centimeter‐scale polymeric thin‐films are covalently cross‐linked, dynamic in nature, featuring tunable thickness (6–200 nm) and significant morphological variations are realized under the influence of varying reaction time, concentration and types of reducing agents. Notably, C3N3S3 polymer thin films exhibit a transflectance of around 99.5% in the range from 430 to 1800 nm, show high refractive indices (1.730–1.488) and optical anisotropy with uniaxial negative birefringence. The C3N3S3 free‐standing polymer thin‐films can be easily transferred to different substrates or possibly into application‐relevant forms for device fabrications, making this useful from materials application perspective. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Layer‐By‐Layer Assembly of Asymmetric Linkers into Non‐Centrosymmetric Metal Organic Frameworks: A Thorough Theoretical Treatment.

Author

Liu, Modan, Elsing, David, Esmaeilpour, Meysam, Kozlowska, Mariana, Wenzel, Wolfgang, and Wöll, Christof

Subjects
METAL-organic frameworks, SECOND harmonic generation, MONTE Carlo method, ELECTROSTATIC fields, MULTISCALE modeling, THERMODYNAMIC equilibrium
Abstract

Layer‐by‐layer synthesis of surface‐coordinated metal–organic frameworks (SURMOF) enables the assembly of asymmetric, dipolar linkers into non‐centrosymmetric pillar‐layered structures. Using appropriate substrate terminations can yield oriented growth with the dipoles aligned perpendicular to the surface. The aligned pillar linkers give rise to a built‐in electrostatic field. In addition, the non‐centrosymmetric structure of the SURMOF gives rise to intriguing nonlinear optical features, such as second harmonic generation. Previous research with methyl‐functionalized bipyridine pillar linkers have demonstrated that this approach works in principle, but so far the total degree of alignment is only very small. Herein, a multiscale modelling approach is presented for in‐silico SURMOF assembly to identify and overcome limitations in the growth of pillar‐layered SURMOFs and to develop a strategy to maximize linker alignment. Using master equation models and kinetic Monte Carlo simulations, it is found that the formation of a highly ordered state corresponding to the thermodynamic equilibrium is often prevented by long‐lasting transient effects. Based on ab initio binding energies for a wide selection of hypothetical pillar linkers, a fast‐binding, slow‐relaxation scheme is able to be identified during the SURMOF growth for a range of different pillar linkers. These observations allow them to derive a rational strategy for the design of novel linkers to yield SURMOF‐based non‐centrosymmetric materials with substantially improved properties. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Twisting of Porphyrin by Assembly in a Metal‐Organic Framework yielding Chiral Photoconducting Films for Circularly‐Polarized‐Light Detection

Author

Li, Chun, primary, Schopmans, Henrik, additional, Langer, Lukas, additional, Marschner, Stefan, additional, Chandresh, Abhinav, additional, Bürck, Jochen, additional, Tsuchiya, Youichi, additional, Chihaya, Adachi, additional, Wenzel, Wolfgang, additional, Bräse, Stefan, additional, Kozlowska, Mariana, additional, and Heinke, Lars, additional

Published
2023
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19. Inside Back Cover: Twisting of Porphyrin by Assembly in a Metal‐Organic Framework yielding Chiral Photoconducting Films for Circularly‐Polarized‐Light Detection (Angew. Chem. Int. Ed. 10/2023)

Author

Li, Chun, primary, Schopmans, Henrik, additional, Langer, Lukas, additional, Marschner, Stefan, additional, Chandresh, Abhinav, additional, Bürck, Jochen, additional, Tsuchiya, Youichi, additional, Chihaya, Adachi, additional, Wenzel, Wolfgang, additional, Bräse, Stefan, additional, Kozlowska, Mariana, additional, and Heinke, Lars, additional

Published
2023
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20. Chirales Porphyrin durch Einbau in metallorganisches Gerüst erlaubt fotoleitende Filme für die Detektion von zirkular polarisiertem Licht

Author

Li, Chun, primary, Schopmans, Henrik, additional, Langer, Lukas, additional, Marschner, Stefan, additional, Chandresh, Abhinav, additional, Bürck, Jochen, additional, Tsuchiya, Youichi, additional, Chihaya, Adachi, additional, Wenzel, Wolfgang, additional, Bräse, Stefan, additional, Kozlowska, Mariana, additional, and Heinke, Lars, additional

Published
2023
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26. Solid and Hollow Poly(p-xylylene) Particles Synthesis via Metal–Organic Framework-Templated Chemical Vapor Polymerization

Author

Begum, Salma, primary, Behboodi-Sadabad, Farid, additional, Pramudya, Yohanes, additional, Dolle, Christian, additional, Kozlowska, Mariana, additional, Hassan, Zahid, additional, Mattern, Cornelia, additional, Gorji, Saleh, additional, Heißler, Stefan, additional, Welle, Alexander, additional, Koenig, Meike, additional, Wenzel, Wolfgang, additional, Eggeler, Yolita M., additional, Bräse, Stefan, additional, Lahann, Joerg, additional, and Tsotsalas, Manuel, additional

Published
2022
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27. Two- and three-photon processes in photoinitiators for 3D laser printing

Author

Mauri, Anna, primary, Kiefer, Pascal, additional, Neidinger, Philipp, additional, Messer, Tobias, additional, Bojanowski, N. Maximilian, additional, Yang, Liang, additional, Walden, Sarah, additional, Unterreiner, Andreas-Neil, additional, Barner-Kowollik, Christopher, additional, Wegener, Martin, additional, Wenzel, Wolfgang, additional, and Kozlowska, Mariana, additional

Published
2022
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28. Hierarchical coarse-grained strategy for macromolecular self-assembly : application to hepatitis B virus-like particles

Author

Depta, Philipp Nicolas, Dosta, Maksym, Wenzel, Wolfgang, Kozlowska, Mariana, Heinrich, Stefan, Depta, Philipp Nicolas, Dosta, Maksym, Wenzel, Wolfgang, Kozlowska, Mariana, and Heinrich, Stefan

Abstract

Macromolecular self-assembly is at the basis of many phenomena in material and life sciences that find diverse applications in technology. One example is the formation of virus-like particles (VLPs) that act as stable empty capsids used for drug delivery or vaccine fabrication. Similarly to the capsid of a virus, VLPs are protein assemblies, but their structural formation, stability, and properties are not fully understood, especially as a function of the protein modifications. In this work, we present a data-driven modeling approach for capturing macromolecular self-assembly on scales beyond traditional molecular dynamics (MD), while preserving the chemical specificity. Each macromolecule is abstracted as an anisotropic object and high-dimensional models are formulated to describe interactions between molecules and with the solvent. For this, data-driven protein–protein interaction potentials are derived using a Kriging-based strategy, built on high-throughput MD simulations. Semi-automatic supervised learning is employed in a high performance computing environment and the resulting specialized force-fields enable a significant speed-up to the micrometer and millisecond scale, while maintaining high intermolecular detail. The reported generic framework is applied for the first time to capture the formation of hepatitis B VLPs from the smallest building unit, i.e., the dimer of the core protein HBcAg. Assembly pathways and kinetics are analyzed and compared to the available experimental observations. We demonstrate that VLP self-assembly phenomena and dependencies are now possible to be simulated. The method developed can be used for the parameterization of other macromolecules, enabling a molecular understanding of processes impossible to be attained with other theoretical models., Macromolecular self-assembly is at the basis of many phenomena in material and life sciences that find diverse applications in technology. One example is the formation of virus-like particles (VLPs) that act as stable empty capsids used for drug delivery or vaccine fabrication. Similarly to the capsid of a virus, VLPs are protein assemblies, but their structural formation, stability, and properties are not fully understood, especially as a function of the protein modifications. In this work, we present a data-driven modeling approach for capturing macromolecular self-assembly on scales beyond traditional molecular dynamics (MD), while preserving the chemical specificity. Each macromolecule is abstracted as an anisotropic object and high-dimensional models are formulated to describe interactions between molecules and with the solvent. For this, data-driven protein–protein interaction potentials are derived using a Kriging-based strategy, built on high-throughput MD simulations. Semi-automatic supervised learning is employed in a high performance computing environment and the resulting specialized force-fields enable a significant speed-up to the micrometer and millisecond scale, while maintaining high intermolecular detail. The reported generic framework is applied for the first time to capture the formation of hepatitis B VLPs from the smallest building unit, i.e., the dimer of the core protein HBcAg. Assembly pathways and kinetics are analyzed and compared to the available experimental observations. We demonstrate that VLP self-assembly phenomena and dependencies are now possible to be simulated. The method developed can be used for the parameterization of other macromolecules, enabling a molecular understanding of processes impossible to be attained with other theoretical models.

Published
2022
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32. Cover Feature: Tetrazole and Oxadiazole Derivatives as Thermally Activated Delayed Fluorescence Emitters (Chem. Eur. J. 57/2024).

Author

Leonhardt, Céline, Mauri, Anna, Garin, Idoia, Rosemann, Nils W., Wenzel, Wolfgang, Lemmer, Uli, Kozlowska, Mariana, and Bräse, Stefan

Subjects
DELAYED fluorescence, PHOTOLUMINESCENCE, OXADIAZOLES
Abstract

This article, titled "Cover Feature: Tetrazole and Oxadiazole Derivatives as Thermally Activated Delayed Fluorescence Emitters," discusses the use of star-like molecules decorated with oxadiazoles and carbazoles as blue-green emitters. These molecules have shown optimal performance with an 88% photoluminescence quantum yield and fast rates of reversible intersystem crossing. The article provides more information on this topic and can be found in the Research Article by M. Kozlowska, S. Bräse, and co-workers. [Extracted from the article]

Published
2024
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33. Stabilization of Pancake Bonding in (TCNQ)2.− Dimers in the Radical‐Anionic Salt (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN) Solvate and Antiferromagnetism Induction

Author

Starodub, Tetiana N., Čižmár, Erik, Kliuikov, Andrii, Starodub, Vladimir A., Feher, Alexander, and Kozlowska, Mariana

Subjects
lcsh:Chemistry, radical ions, charge transfer processes, lcsh:QD1-999, crystal engineering, Communication, density functional calculations, magnetic properties, Communications
Abstract

We report a new antiferromagnetic radical‐anion salt (RAS) formed from 7,7,8,8‐tetracyanquinonedimethane (TCNQ) anion and 2‐amino‐5‐chloro‐pyridine cation with the composition of (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN). The crystallographic data indicates the formation of (TCNQ)2 .− radical‐anion π‐dimers in the synthesized RAS. Unrestricted density functional theory calculations show that the formed π‐dimers characterize with strong π‐stacking “pancake” interactions, resulting in high electronic coupling, enabling efficient charge transfer properties, but π‐dimers cannot be stable in the isolated conditions as a result of strong Coulomb repulsions. In a crystal, where (TCNQ)2 .− π‐dimers bound in the endless chainlets via supramolecular bonds with (N−CH3−2‐NH2−5‐Cl−Py)+ cations, the repulsion forces are screened, allowing for specific parallel π‐stacking interactions and stable radical‐anion dimers formation. Measurements of magnetic susceptibility and magnetization confirm antiferromagnetic properties of RAS, what is in line with the higher stability of ground singlet state of the radical‐anion pair, calculated by means of the DFT. Therefore, the reported radical‐anion (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN) solvate has promising applications in novel magnetics with supramolecular structures.

Published
2019

37. Interplay of structural dynamics and electronic effects in an engineered assembly of pentacene in a metal–organic framework

Author

Haldar, Ritesh, primary, Kozlowska, Mariana, additional, Ganschow, Michael, additional, Ghosh, Samrat, additional, Jakoby, Marius, additional, Chen, Hongye, additional, Ghalami, Farhad, additional, Xie, Weiwei, additional, Heidrich, Shahriar, additional, Tsutsui, Yusuke, additional, Freudenberg, Jan, additional, Seki, Shu, additional, Howard, Ian A., additional, Richards, Bryce S., additional, Bunz, Uwe H. F., additional, Elstner, Marcus, additional, Wenzel, Wolfgang, additional, and Wöll, Christof, additional

Published
2021
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38. (Invited) The Interplay of Conformation and Electronic Structure in Metal Organic Frameworks

Author

Pramudya, Yohanes, primary, Kozlowska, Mariana, additional, Heidrich, Shahriar, additional, Krstić, Marjan, additional, Haldar, Ritesh, additional, Neumann, Tobias, additional, Schlöder, Tobias, additional, Zhang, Qiang, additional, Symalla, Franz, additional, Hassan, Zeinab Mohamed, additional, Liu, Xiaojing, additional, Heinke, Lars, additional, Woell, Christof, additional, and Wenzel, Wolfgang, additional

Published
2020
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39. Tuning Optical Properties by Controlled Aggregation: Electroluminescence Assisted by Thermally‐Activated Delayed Fluorescence from Thin Films of Crystalline Chromophores

Author

Haldar, Ritesh, primary, Jakoby, Marius, additional, Kozlowska, Mariana, additional, Rahman Khan, Motiur, additional, Chen, Hongye, additional, Pramudya, Yohanes, additional, Richards, Bryce S., additional, Heinke, Lars, additional, Wenzel, Wolfgang, additional, Odobel, Fabrice, additional, Diring, Stéphane, additional, Howard, Ian A., additional, Lemmer, Uli, additional, and Wöll, Christof, additional

Published
2020
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42. Photoconductivity in Metal–Organic Framework (MOF) Thin Films

Author

Liu, Xiaojing, primary, Kozlowska, Mariana, additional, Okkali, Timur, additional, Wagner, Danny, additional, Higashino, Tomohiro, additional, Brenner‐Weiß, Gerald, additional, Marschner, Stefan M., additional, Fu, Zhihua, additional, Zhang, Qiang, additional, Imahori, Hiroshi, additional, Bräse, Stefan, additional, Wenzel, Wolfgang, additional, Wöll, Christof, additional, and Heinke, Lars, additional

Published
2019
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43. Photoleitfähigkeit in Dünnfilmen Metall‐organischer Gerüste

Author

Liu, Xiaojing, primary, Kozlowska, Mariana, additional, Okkali, Timur, additional, Wagner, Danny, additional, Higashino, Tomohiro, additional, Brenner‐Weiß, Gerald, additional, Marschner, Stefan M., additional, Fu, Zhihua, additional, Zhang, Qiang, additional, Imahori, Hiroshi, additional, Bräse, Stefan, additional, Wenzel, Wolfgang, additional, Wöll, Christof, additional, and Heinke, Lars, additional

Published
2019
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45. Highly Efficient One-Dimensional Triplet Exciton Transport in a Palladium–Porphyrin-Based Surface-Anchored Metal–Organic Framework

Author

Adams, Michael, primary, Kozlowska, Mariana, additional, Baroni, Nicolò, additional, Oldenburg, Michael, additional, Ma, Rui, additional, Busko, Dmitry, additional, Turshatov, Andrey, additional, Emandi, Ganapathi, additional, Senge, Mathias O., additional, Haldar, Ritesh, additional, Wöll, Christof, additional, Nienhaus, G. Ulrich, additional, Richards, Bryce S., additional, and Howard, Ian A., additional

Published
2019
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50. Stabilization of Pancake Bonding in (TCNQ)2.− Dimers in the Radical‐Anionic Salt (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN) Solvate and Antiferromagnetism Induction.

Author

Starodub, Tetiana N., Čižmár, Erik, Kliuikov, Andrii, Starodub, Vladimir A., Feher, Alexander, and Kozlowska, Mariana

Subjects
MAGNETIC measurements, DIMERS, ANTIFERROMAGNETISM, MAGNETIC susceptibility, CHARGE transfer, STACKING interactions
Abstract

We report a new antiferromagnetic radical‐anion salt (RAS) formed from 7,7,8,8‐tetracyanquinonedimethane (TCNQ) anion and 2‐amino‐5‐chloro‐pyridine cation with the composition of (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN). The crystallographic data indicates the formation of (TCNQ)2.− radical‐anion π‐dimers in the synthesized RAS. Unrestricted density functional theory calculations show that the formed π‐dimers characterize with strong π‐stacking "pancake" interactions, resulting in high electronic coupling, enabling efficient charge transfer properties, but π‐dimers cannot be stable in the isolated conditions as a result of strong Coulomb repulsions. In a crystal, where (TCNQ)2.− π‐dimers bound in the endless chainlets via supramolecular bonds with (N−CH3−2‐NH2−5‐Cl−Py)+ cations, the repulsion forces are screened, allowing for specific parallel π‐stacking interactions and stable radical‐anion dimers formation. Measurements of magnetic susceptibility and magnetization confirm antiferromagnetic properties of RAS, what is in line with the higher stability of ground singlet state of the radical‐anion pair, calculated by means of the DFT. Therefore, the reported radical‐anion (N−CH3−2‐NH2−5Cl−Py)(TCNQ)(CH3CN) solvate has promising applications in novel magnetics with supramolecular structures. [ABSTRACT FROM AUTHOR]

Published
2019
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