A5015872488- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Advanced NMR Techniques and Applications
- Covalent Organic Framework Applications
- DNA and Nucleic Acid Chemistry
- Metal-Organic Frameworks: Synthesis and Applications
- X-ray Diffraction in Crystallography
- Molecular spectroscopy and chirality
- Advanced Photocatalysis Techniques
- Crystallization and Solubility Studies
- Machine Learning in Materials Science
- Protein Structure and Dynamics
- Crystallography and molecular interactions
- Electron Spin Resonance Studies
- Inorganic Fluorides and Related Compounds
- Chemical Synthesis and Analysis
- Molecular Spectroscopy and Structure
- Photochemistry and Electron Transfer Studies
- Inorganic Chemistry and Materials
- RNA and protein synthesis mechanisms
- Solid-state spectroscopy and crystallography
- DNA Repair Mechanisms
- Gas Sensing Nanomaterials and Sensors
- Magnetism in coordination complexes
- Luminescence and Fluorescent Materials
Ludwig-Maximilians-Universität München
2016-2025
Max Planck Institute for Solid State Research
2018-2025
Institute of Theoretical Physics
2025
LMU Klinikum
2015-2023
Center for NanoScience
2017-2021
Excellence Cluster Universe
2020-2021
Korea University
2021
Center for Integrated Protein Science Munich
2013-2019
Nanosystems Initiative Munich
2018
University of Münster
2015
Abstract Hydrogen evolution from photocatalytic reduction of water holds promise as a sustainable source carbon-free energy. Covalent organic frameworks (COFs) present an interesting new class photoactive materials, which combine three key features relevant to the process, namely crystallinity, porosity and tunability. Here we synthesize series water- photostable 2D azine-linked COFs hydrazine triphenylarene aldehydes with varying number nitrogen atoms. The electronic steric variations in...
Q-Chem 2.0 is a new release of an electronic structure program package, capable performing first principles calculations on the ground and excited states molecules using both density functional theory wave function-based methods. A review technical features contained within presented. This article contains brief descriptive discussions key physical all algorithms theoretical models, together with sample that illustrate their performance. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 1532–1548,
Covalent organic frameworks (COFs) are a new class of nanoporous polymeric vector showing promise as drug-delivery vehicles with high loading capacity and biocompatibility. The interaction between the carrier cargo is specifically tailored on molecular level by H-bonding. Cell-proliferation studies indicate higher efficacy drug in cancer cells nanocarrier delivery mediated COF.
We demonstrate photocatalytic hydrogen evolution using COF photosensitizers with molecular proton reduction catalysts for the first time. With azine-linked N2-COF photosensitizer, chloro(pyridine)cobaloxime co-catalyst, and TEOA donor, H2 rate of 782 μmol h–1 g–1 TON 54.4 has been obtained in a water/acetonitrile mixture. PXRD, solid-state spectroscopy, EM analysis, quantum-chemical calculations suggest an outer sphere electron transfer from to co-catalyst which subsequently follows...
Stabilization of covalent organic frameworks (COFs) by post-synthetic locking strategies is a powerful tool to push the limits COF utilization, which are imposed reversible linkage. Here we introduce sulfur-assisted chemical conversion two-dimensional imine-linked into thiazole-linked COF, with full retention crystallinity and porosity. This modification entails significantly enhanced electron beam stability, enabling investigation real framework structure at high level detail. An in-depth...
Solar hydrogen (H2) evolution from water utilizing covalent organic frameworks (COFs) as heterogeneous photosensitizers has gathered significant momentum by virtue of the COFs' predictive structural design, long-range ordering, tunable porosity, and excellent light-harvesting ability. However, most photocatalytic systems involve rare expensive platinum co-catalyst for reduction, which appears to be bottleneck in development economical environmentally benign solar H2 production systems....
Solving the structure of carbon nitrides has been a long-standing challenge due to low crystallinity and complex structures observed within this class earth-abundant photocatalysts. Herein, we report on two-dimensional layered potassium poly(heptazine imide) (K-PHI) its proton-exchanged counterpart (H-PHI), obtained by ionothermal synthesis using molecular precursor route. We present comprehensive analysis in-plane three-dimensional PHI. Transmission electron microscopy solid-state NMR...
The use of covalent organic frameworks (COFs) in environmental settings such as atmospheric water capture or CO2 separation under realistic pre- and post-combustion conditions is largely unexplored to date. Herein, we present two isostructural azine-linked COFs based on 1,3,5-triformyl benzene (AB-COF) 1,3,5-triformylphloroglucinol (ATFG-COF) hydrazine building units, respectively, whose sorption characteristics are precisely tunable by the rational design chemical nature pore walls. This...
Covalent organic frameworks (COFs) are an extensively studied class of porous materials, which distinguish themselves from other polymers in their crystallinity and high degree modularity, enabling a wide range applications. COFs most commonly synthesized solvothermally, is often time-consuming process restricted to well-soluble precursor molecules. Synthesis polyimide-linked (PI-COFs) further complicated by the poor reversibility ring-closing reaction under solvothermal conditions. Herein,...
Abstract Covalent organic frameworks (COFs) have emerged as a new class of crystalline porous polymers displaying molecular tunability combined with structural definition. Here, series three conjugated, photoactive azine‐linked COFs based on pyrene building blocks which differ in the number nitrogen atoms peripheral aromatic units is presented. The structure analyzed by experimental and computational physisorption well quantum‐chemical calculations, suggest slipped‐stacked arrangement 2D...
Covalent organic frameworks (COFs) display a unique combination of chemical tunability, structural diversity, high porosity, nanoscale regularity, and thermal stability. Recent efforts are directed at using such as tunable scaffolds for reactions. In particular, COFs have emerged viable platforms mimicking natural photosynthesis. However, there is an indisputable need efficient, stable, economical alternatives the traditional platinum-based cocatalysts light-driven hydrogen evolution. Here,...
Covalent organic frameworks (COFs) are typically designed by breaking down the desired network into feasible building blocks - either simple and highly symmetric, or more convoluted thus less symmetric. The linkers chosen complementary to each other such that an extended, fully condensed structure can form. We show not only exception, but a design principle allows free of rules. tri- tetratopic be combined form imine-linked [4 + 3] sub-stoichiometric 2D COFs featuring unexpected bex net...
We computationally dissected the electronic and geometrical influences of ortho-chlorinated azobenzenes on their photophysical properties. X-ray analysis provided insight that trans-tetra-ortho-chloro azobenzene is conformationally flexible thus subject to molecular motions. This allows photoswitch adopt a range red-shifted geometries, which account for extended n → π* band tails. On basis our results, we designed di-ortho-fluoro di-ortho-chloro (dfdc) computational evidence superiority this...
Covalent organic frameworks have emerged as a powerful synthetic platform for installing and interconverting dedicated molecular functions on crystalline polymeric backbone with atomic precision. Here, we present novel strategy to directly access amine-linked covalent frameworks, which serve scaffold enabling pore-wall modification linkage-interconversion by new methods based Leuckart-Wallach reduction formic acid ammonium formate. Frameworks connected entirely secondary amine linkages,...
Herein, we report a facile postsynthetic linkage conversion method giving synthetic access to nitrone-linked covalent organic frameworks (COFs) from imine- and amine-linked COFs. The new two-dimensional (2D) frameworks, NO-PI-3-COF NO-TTI-COF, are obtained with high crystallinity large surface areas. Nitrone-modified pore channels induce condensation of water vapor at 20% lower humidity compared their amine- or imine-linked precursor Thus, the topochemical transformation nitrone linkages...
We present a new method (LinK) to form the exact exchange matrix, as needed in Hartree–Fock and hybrid density functional theory calculations, with an effort capable of scaling only linearly molecular size. It preserves highly optimized structure conventional direct self-consistent field (SCF) methods negligible prescreening overhead does not impose predefined decay properties. Our LinK leads very early advantages compared for systems larger band gaps. Due screening it is also competitive...
An extensive study of error distributions for calculating hydrogen and carbon NMR chemical shifts at Hartree–Fock (HF), density functional theory (DFT), Møller–Plesset second-order perturbation (MP2) levels is presented. Our investigation employs accurate CCSD(T)/cc-pVQZ calculations providing reference data 48 40 nuclei within an extended set compounds covering a broad range the scale with high relevance to applications, especially in organic chemistry. Besides approximations HF, variety...
A Laplace-transformed second-order Møller–Plesset perturbation theory (MP2) method is presented, which allows to achieve linear scaling of the computational effort with molecular size for electronically local structures. Also systems a delocalized electronic structure, cubic or even quadratic behavior achieved. Numerically significant contributions atomic orbital (AO)-MP2 energy are preselected using so-called multipole-based integral estimates (MBIE) introduced earlier by us [J. Chem. Phys....
We present a simple but accurate preselection method based on Schwarz integral estimates to determine the significant elements of exact exchange matrix before its evaluation, thus providing an asymptotical linear-scaling behavior for non-metallic systems. Our screening procedure proves be highly suitable calculations massively parallel computing architectures, such as graphical processing units, which we first evaluation algorithm.
The influence of the chemical environment on NMR shifts a central molecular region is studied for several biomolecular and supramolecular systems. To investigate long-range effects, we systematically increase QM until changes shielding tensor are negligible considered nuclei; that is, convergence with selected size reached. reach convergence, regions up to about 1500 atoms 15 000 basis functions treated by our density matrix-based linear-scaling coupled perturbed self-consistent field...
Abstract Carbon nitrides constitute a class of earth‐abundant polymeric semiconductors, which have high potential for tunability on molecular level, despite their chemical and thermal inertness. Here the first postsynthetic modification 2D carbon nitride poly(heptazine imide) (PHI) is reported, decorated with terminal melamine (Mel) moieties by functional group interconversion. The covalent attachment this verified based suite spectroscopic microscopic techniques supported quantum–chemical...
We present an extension of our recently presented PreLinK scheme (J. Chem. Phys. 2013, 138, 134114) for the exact exchange contribution to nuclear forces. The significant contributions gradient are determined by preselection based on accurate shell-pair SCF energy prior calculation. Therefore, method is highly suitable massively parallel electronic structure calculations because efficient load balancing only and unhampered control flow. efficiency shown several illustrative single GPU...
Organic solids such as covalent organic frameworks (COFs), porous polymers and carbon nitrides have garnered attention a new generation of photocatalysts that offer tunability their optoelectronic properties both at the molecular level nanoscale. Owing to inherent porosity well-ordered nanoscale architectures, COFs are an especially attractive platform for rational design light-induced hydrogen evolution. In this report, our previous strategy altering nitrogen content in azine-linked COF...