PD Dr. Simon Grabowsky

Alumni

University of Bern

• Dr. Ana Stucki-Mafud
• Sergey Fisher
  now at Free University of Amsterdam
• Sinas Furan
  now at the University of Bremen
• Dr Ravish Sankolli
• Dr Michał Andrzejewski
  now at Paul Scherrer Institute PSI
• Dr Florian Kleemiß
  now at the University of Regensburg
• Vasyl Stotskyi
  now at Paul Scherrer Institute PSI

University of Bremen

• Dr Pim Puylaert
  now at the University of Bremen
• Arta Safari
  now at MPI for Solid State Research, Stuttgart
• Dr Malte Fugel
  now at TÜV Nord, Hanover
• Dr Rumpa Pal
  subsequently University of Tsukuba
• Erna Wieduwilt
  now at the University of Lorraine
• Justin Bergmann
  now at European Spallation Source, Lund
• Anneke Dittmer
  now at MPI für Kohlenforschung, Mülheim an der Ruhr
• Dr Maksym Ponomarenko
• Dr Emanuel Hupf
  now at the University of Bremen
• Dr Maxie F. Hesse
  subsequently University of Bremen

The University of Western Australia

• Mingwen Shi
• Dr Joanna M. Krzeszczakowska, née Bąk
  now at Jozef Poniatowski Fifth Secondary Comprehensive School, Warsaw

Our main field of research is method development in quantum crystallography and application of the new methods to bonding analysis in inorganic and bio-organic chemistry.

Method Development: X-ray Wavefunction Refinement

Conventional methods for structure determination using single-crystal X-ray diffraction data neglect the deformation of the valence electron density, but only model atoms with spherical electron densities. However, it is exactly those valence deformations into bonding and lone-pair regions that are the heart of chemistry. Therefore methods were developed to determine the total electron density experimentally (multipole model, maximum entropy methods), which are unfortunately only accessible to experts. Our new method X-ray wavefunction refinement (XWR) employs quantum chemistry in order to interpret the diffraction experiment in a simple fashion. Its first step Hirshfeld Atom Refinement (HAR) makes localisation of hydrogen atoms from the X-ray data as precise and accurate as from neutron-diffraction data. The second step X-ray constrained wavefunction (XCW) fitting allows to extract crystal field effects, electron correlation and relativistic effects from the experimental data. We continuously improve XWR and work on a corresponding software (HARt implemented into Olex2).

Relativistic Effects in the Electron Density

In order to extract relativistic effects with our new method XWR from single-crystal X-ray diffraction data, we synthesise and crystallise organo-metallic molecular compounds bearing heavy elements of the 6th period (e.g., Pt, Au, Hg, Tl, Pb, Bi). Crystal quality must be exceedingly good, so that ultra-high resolution data sets can be measured at the synchrotron SPring-8 in Japan at very low temperatures (< 20K). Subsequently, the data are treated with the method IOTC (infinit order two component) during the crystallographic refinement. Moreover, we carry out many theoretical calculations on test molecules in order to separate effects such as electron correlation, polarisation, core deformation and relativistics from each other.

Electron-Density – Property Relationships in Inorganic Chemistry

We synthesise systematic arrays of compounds that only vary in a single substituent in order to correlate geometric with electron-density parameters across the array. This way, reactions or other chemical processes can be simluated through static crystallographic snapshots along a pseudo-coordinate. Each of these snapshots exhibits a complete experimental electron-density study so that deep insights into the electronic nature of the processes can be gained. Currently we work on penta-coordinated silyl naphtalene compounds peri-substituted with amines that represent an attacking group in a nucleophilic substitution reaction with the varying substituent at the silicon atom representing the leaving group. Other compounds of recent interest are siloxanes where we investigate the change of basicity relative to the Si-O-Si bond angle. The concept can be extended to many other systems and chemical processes.

Academic Positions

• since 08/2019: Research Group Leader and Privatdozent at the Department of Chemistry, Biochemistry and Pharmaceutical Sciences at the University of Bern
• 10/2015 – 07/2019: Extraordinary Professor at the University of Bremen
• 09/2014 – 07/2019: Emmy Noether Research Group Leader at the University of Bremen
• 01/2014 – 08/2014: Assistant Research Professor at the University of Western Australia
• 01/2011 – 01/2014: Australian Postdoctoral Fellow at the University of Western Australia
• 10/2006 – 12/2010: Research assistent at the Free University of Berlin

Education

• 10/2019: Habilitation in Physical Chemistry (venia docendi) at the University of Bern
• 04/2019: Habilitation in Physical Chemistry (venia legendi) at the University of Bremen
• 10/2006 – 12/2010: Doctoral studies and dissertation (Prof Dr Peter Luger): "New Methods in the Analysis of Electron Density and Electron Localizability - Applications to X-O-X Systems (X = C, Si)", Free University of Berlin
• 10/2001 – 09/2006: Studies of chemistry (diploma) at the Free University of Berlin

Societies and Organisations

• Member of Commission on Quantum Crystallography of the International Union of Crystallography
• President of the Swiss Society for Crystallography
• Treasurer of Bernese Chemical Society
• Member of the European Crystallographic Association
• Member of Swiss Chemical Society
• Member of Gesellschaft Deutscher Chemiker
• Member of Deutsche Gesellschaft für Kristallograhie (DGK)

Publications recorded in the new BORIS (Bern Open Repository and Information System) Portal: 

Frühjahr 2025

Quantenchemie (mit Prof. Dr. Natalie Banerji) - Vorlesung im Bachelor-Studium

Pharmazeutische Analytik (mit Prof. Dr. Stefan Schürch, Prof. Dr. Sönke Szidat, Prof. Dr. Julien Furrer) -  Workshop zu Fallstudien

Herbst 2024

Inorganic Chemistry I (with Prof Eva Hevia Freire) - undergraduate course, lectures and excercises

Inorganic Chemistry II (in groups) - undergraduate course, lab class

Chemical Crystallography - graduate course, lectures

Symmetrielehre (mit Prof. Dr. Natalie Banerji) - Vorlesung im Bachelor-Studium

Universität Bremen

Allgemeine Chemie - Vorlesung im Bachelor-Studium

Theorie der Chemischen Bindungen - Vorlesung und Übung im Bachelor-Studium

Anwendung der Theoretischen Chemie - Vorlesung im Master-Studium

Quantum Crystallography - graduate course, lab

Quantenchemie - Übung im Bachelor-Studium

The University of Western Australia

Theoretical Chemistry - undergraduate course, tutorials

Structure Determination in Chemistry - undergraduate course, tutorials

Freie Universität Berlin

Mathematik I und II - Übung im Bachelor-Studium

Single crystal X-ray diffraction

Single crystal X-ray diffraction is a powerful technique, used to study the structure of solids (organic, inorganic or metallorganic). In particular, it provides the type and dimensions of a crystal lattice and the precise positions of atoms in the unit cell. The technique requires single crystal samples (no policrystals, no twinned) of at least 01 x 0.1 x 0.1 mm size. The experiment can be carried out in protected environment in a temperature range 90-400 K. The diffraction experiment normally takes one day of measurement and one day of crystal structure solution and refinement. The ARS team provides a crystallographic information file (cif) for visualisation and analysis, tables of atomic positions and bond distances, full description of the experiment in a format ready for publication.

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