RESEARCH
GROUP OF
PROF. H.-H.
LIMBACH
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ACTUAL
RESEARCH
AREA OF
PROF. H.-H.
LIMBACH
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Abstract
The current research program is focused on the design and the
study by NMR spectroscopy of the structure and dynamics of isotopically
labeled molecular model systems for proton and hydride transfer.
The range between small organic molecules embedded in liquids,
solids and surfaces, modified enzymes, oligonucleotides and transition
metal hydrides is covered. The whole instrumentarium of variable
temperature liquid and solid state NMR spectroscopy is applied.
The aim is to measure kinetic, equilibrium and geometric isotope
and tunnel effects of hydrogen transfer in high- and low-barrier
hydrogen bonds and in the coordination sphere of transition metal
catalysts, and to model the results theoretically. A substantial
part of the work is done in collaboration with other research
groups specialized in other areas of spectroscopy, synthetic and
theoretical chemistry, supramolecular-, polymer- and biochemistry,
material and surface science.
Topics for research laboratory stages
Physical-chemical research regarding the structure and dynamic
of molecules in condensed phases via NMR-spectroscopy; organic
molecule crystals and glass, amorph solids, polymers; reaction
kinetics in sol.; kinetic isotope effects; isotope labelling.In
the future: Low temperature liquids, interfaces, colloids; structure
and dynamic of biomolecules in liquids and solid states; biological
objects.
Skills acquired during the laboratory stage
Synthesis of isotopically labeled compounds, liquid and solid
state NMR spectroscopy at low temperatures, NMR as a tool for
the study of kinetic processes, especially proton transfer, NMR-lineshape
analysis, ab initio calculations
Further Reading
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ACTUAL
RESEARCH
AREA OF
DR. G.
BUNTKOWSKY
Abstract
Principal research area is the study of complex
heterogeneous systems with solid state NMR spectroscopy.
For the characterization of heterogeneous and/or
amorphous materials a technique is needed which on one hand is able to
look beyond the surface of the material and which on the other hand does
not depend on regular (crystalline) order, like most diffraction techniques.
The experimental technique which is capable for these studies is solid
state NMR spectroscopy, which allows to directly investigate interactions
between different compounds (for example host/guest complexes) in a
heterogeneous system, which are reflected in the local spatial structure of the
host guest complex (aggregate). By suitable combination of different isotopes
(selective isotope labelling) it is possible to map out the interesting
structures in the aggregate. Primarily different double resonance and triple
resonance solid state NMR techniques (REDOR,TEDOR,SEDOR, Multiple Quantum
NMR, CP- MAS (cross polarization and magic angle spinning) spectroscopy,
tensor correlation, etc.) are used for the analysis of magnetic dipolar
interactions in the interesting compounds. Other research activities include
low temperature NMR spectroscopy in particular 2H solid state
NMR spectroscopy of h-bound di-deuterium metal
complexes to look for 2H-NMR tunneling and theoretical studies
of spin dynamics. For the future it is planned to start with field gradient
NMR (either switched field gradient or static gradient) for diffusion measurements
in porous systems. Most experiments are run on a home built three channel
solid state NMR spectrometer operated at 7Tesla.
Topics for research laboratory stages
Study of 13C- 15N dipolar
interactions in selectively labelled organic compounds. 2H-NMR
investigations of hapdo-bound di-deuterium metal
complexes.
Skills acquired during the laboratory stage
A solid knowledge of experimental solid state NMR on a home built
spectrometer (i.e. not a black box) is acquired. Depending on
the chosen topic (VT and low temperature solid state NMR or study
of dipolar interactions in solids) additional skills are acquired
either in the handling of a He flow cryostat system and spin
echo techniques for measuring 2H-NMR spectra and relaxation
times at low temperatures or in modern MAS techniques for dipolar
recoupling.
Further Reading
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ACTUAL
RESEARCH
AREA OF
DR. K.
WEISZ
Abstract
NMR studies on the structure and stability of nucleic acids und proteins.
Topics for research laboratory stages
Synthesis of oligonucleotides with non-natural and isotope-labeled
nucleosides.
NMR studies on hydrogen bonds in nucleic acids
3D structure determination of antisense and antigene oligonucleotides
Skills acquired during the laboratory stage
Nucleoside chemistry, preparation and purification of oligonucleotides,
multi-dimensional homo- and heteronuclear NMR spectroscopy
Further Reading
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