FG Theoretische Chemie - Quantenchemie

14 Items

Recent Submissions
Vibrational characterization of a diiron bridging hydride complex – a model for hydrogen catalysis

Gee, Leland B. ; Pelmenschikov, Vladimir ; Wang, Hongxin ; Mishra, Nakul ; Liu, Yu-Chiao ; Yoda, Yoshitaka ; Tamasaku, Kenji ; Chiang, Ming-Hsi ; Cramer, Stephen P. (2020-05-06)

A diiron complex containing a bridging hydride and a protonated terminal thiolate of the form [(μ,κ2-bdtH)(μ-PPh2)(μ-H)Fe2(CO)5]+ has been investigated through 57Fe nuclear resonance vibrational spectroscopy (NRVS) and interpreted using density functional theory (DFT) calculations. We report the Fe–μH–Fe wagging mode, and indications for Fe–μD stretching vibrations in the D-isotopologue, observ...

Stable Actinide π Complexes of a Neutral 1,4-Diborabenzene

Paprocki, Valerie ; Hrobárik, Peter ; Harriman, Katie L. M. ; Luff, Martin S. ; Kupfer, Thomas ; Kaupp, Martin ; Murugesu, Muralee ; Braunschweig, Holger (2020-04-24)

The π coordination of arene and anionic heteroarene ligands is a ubiquitous bonding motif in the organometallic chemistry of d-block and f-block elements. By contrast, related π interactions of neutral heteroarenes including neutral bora-π-aromatics are less prevalent particularly for the f-block, due to less effective metal-to-ligand backbonding. In fact, π complexes with neutral heteroarene l...

Development, implementation and validation of excited-state gradients for local hybrid functionals

Grotjahn, Robin (2021)

In the present work, excited-state nuclear gradients within linear-response time-dependent density functional theory are developed for local hybrid functionals (local hybrids). The derived equations are implemented in the quantum chemical program TURBOMOLE using an efficient seminumerical integration scheme. The implementation is used to validate local hybrids for a range of excited-state prope...

Insights from 125Te and 57Fe nuclear resonance vibrational spectroscopy: a [4Fe–4Te] cluster from two points of view

Wittkamp, Florian ; Mishra, Nakul ; Wang, Hongxin ; Wille, Hans-Christian ; Steinbrügge, René ; Kaupp, Martin ; Cramer, Stephen P. ; Apfel, Ulf-Peter ; Pelmenschikov, Vladimir (2019-06-24)

Iron–sulfur clusters are common building blocks for electron transport and active sites of metalloproteins. Their comprehensive investigation is crucial for understanding these enzymes, which play important roles in modern biomimetic catalysis and biotechnology applications. We address this issue by utilizing (Et4N)3[Fe4Te4(SPh)4], a tellurium modified version of a conventional reduced [4Fe–4S]...

Ein neutrales 1,4‐Diborabenzol als π‐Ligand in Actinoidkomplexen

Paprocki, Valerie ; Hrobárik, Peter ; Harriman, Katie L. M. ; Luff, Martin S. ; Kupfer, Thomas ; Kaupp, Martin ; Murugesu, Muralee ; Braunschweig, Holger (2020-05-25)

Die π‐Koordination von Aren‐ und anionischen Heteroarenliganden ist ein allgegenwärtiges Strukturmotiv in der metallorganischen Chemie der d‐ und f‐Block‐Elemente. Im Gegensatz dazu sind vergleichbare π‐Wechselwirkungen neutraler Heteroarene, darunter auch solche neutraler, aromatischer Borheterocyclen, für den f‐Block weit weniger verbreitet, was z. T. mit einer geringeren Effektivität der Met...

TURBOMOLE: Modular program suite for ab initio quantum-chemical and condensed-matter simulations

Balasubramani, Sree Ganesh ; Chen, Guo P. ; Coriani, Sonia ; Diedenhofen, Michael ; Frank, Marius S. ; Franzke, Yannick J. ; Furche, Filipp ; Grotjahn, Robin ; Harding, Michael E. ; Hättig, Christof ; Hellweg, Arnim ; Helmich-Paris, Benjamin ; Holzer, Christof ; Huniar, Uwe ; Kaupp, Martin ; Marefat Khah, Alireza ; Karbalaei Khani, Sarah ; Müller, Thomas ; Mack, Fabian ; Nguyen, Brian D. ; Parker, Shane M. ; Perlt, Eva ; Rappoport, Dmitrij ; Reiter, Kevin ; Roy, Saswata ; Rückert, Matthias ; Schmitz, Gunnar ; Sierka, Marek ; Tapavicza, Enrico ; Tew, David P. ; van Wüllen, Christoph ; Voora, Vamsee K. ; Weigend, Florian ; Wodyński, Artur ; Yu, Jason M. (2020-05-13)

TURBOMOLE is a collaborative, multi-national software development project aiming to provide highly efficient and stable computational tools for quantum chemical simulations of molecules, clusters, periodic systems, and solutions. The TURBOMOLE software suite is optimized for widely available, inexpensive, and resource-efficient hardware such as multi-core workstations and small computer cluster...

Implementation of modern density functional methods

Klawohn, Sascha (2019)

Local hybrid functionals are a relatively new and promising tool in the widely used Kohn-Sham density functional theory, but they have been lacking the capability for structure optimization and vibrational spectroscopic calculations. To close that gap, this thesis is concerned with the implementation and assessment of energy derivatives w.r.t. nuclear displacements (gradients) for local hybrids...

Computation of NMR shifts for paramagnetic solids

Mondal, Arobendo (2019)

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for studying the structural and electronic properties of paramagnetic solids such as battery materials, metal-organic frameworks, and molecular/ionic crystals. However, the interpretation of paramagnetic NMR spectra is often challenging as a result of the interactions of unpaired electrons with the nuclear spins of interest. In th...

Structural Dynamics of Spin Crossover in Iron(II) Complexes with Extended-Tripod Ligands

Stock, Philipp ; Wiedemann, Dennis ; Petzold, Holm ; Hörner, Gerald (2017-09-05)

Selective manipulation of spin states in iron(II) complexes by thermal or photonic energy is a desirable goal in the context of developing molecular functional materials. As dynamic spin-state equilibration in isolated iron(II) complexes typically limits the lifetime of a given spin state to nanoseconds, synthetic strategies need to be developed that aim at inhibited relaxation. Herein we show ...

Assessment and contributions to local hybrid functionals

Seshaditya, A. (2018)

The exchange-correlation energy functional (XC) is the most important ingredient of Kohn-Sham density-functional theory (KS-DFT). Unfortunately this quantity has to be approximated as the exact functional form is not known. But many mathematical studies on density functionals have demonstrated conditions to hold for the exact XC functional. The most important conditions are the stepwise-lineari...

Low frequency dynamics of the nitrogenase MoFe protein via femtosecond pump probe spectroscopy

Maiuri, Margherita ; Delfino, Ines ; Cerullo, Giulio ; Manzoni, Cristian ; Pelmenschikov, Vladimir ; Guo, Yisong ; Wang, Hongxin ; Gee, Leland B. ; Dapper, Christie H. ; Newton, William E. ; Cramer, Stephen P. (2015)

We have used femtosecond pump-probe spectroscopy (FPPS) to study the FeMo-cofactor within the nitrogenase (N2ase) MoFe protein from Azotobacter vinelandii. A sub-20-fs visible laser pulse was used to pump the sample to an excited electronic state, and a second sub-10-fs pulse was used to probe changes in transmission as a function of probe wavelength and delay time. The excited protein relaxes ...

Gas-phase activation of CO2 and CH4 by selected transition-metal complexes: ligand effects and the role of the metal

Firouzbakht, Marjan (2018)

Die vorliegende Arbeit behandelt die Übergangsmetall-vermittelten Aktivierungen von CO2 und CH4, die mittels massenspektrometrischer Methoden und quantenchemischer Rechnungen untersucht wurden. Die Kationen der jeweiligen Übergangsmetalle wurden durch Elektrosprayionisation (ESI) erzeugt und anschließend mit der Tandem-Massenspektrometrie unter Quadrupol-Hexapol-Quadrupol Anordnung charakterisi...

Relativistic effects on electronic structure and nuclear magnetic resonance shifts in heavy metal systems

Greif, Anja Helene (2017)

The role of relativistic effects on the electronic structure and ligand NMR chemical shifts in diamagnetic 5d transition-metal and uranium hydrides as well as organometallic uranium complexes is investigated. New NMR trends and spectral regions for these compounds are suggested based on fully and quasi-relativistic density functional theory calculations carefully calibrated on the experimentall...

Mechanism of the cooperative Si-H bond activation at Ru-S bonds

Stahl, Timo ; Hrobárik, Peter ; Königs, C. David F. ; Ohki, Yasuhiro ; Tatsumi, Kazuyuki ; Kemper, Sebastian ; Kaupp, Martin ; Klare, Hendrik F. T. ; Oestreich, Martin (2015)

The nature of the hydrosilane activation mediated by ruthenium(II) thiolate complexes of type [(R3P)-Ru(SDmp)](+)[BAr4F]- is elucidated by an in-depth experimental and theoretical study. The combination of various ruthenium(II) thiolate complexes and tertiary hydrosilanes under variation of the phosphine ligand and the substitution pattern at the silicon atom is investigated, providing detailed...