Residual dipolar couplings unveil structure of small molecules
New method for unraveling molecular structures
2011-02-18
(Press-News.org) The team of Professor Burkhard Luy from KIT and Junior Professor Stefan F. Kirsch from the TUM has now shown for the first time that certain NMR parameters, the so-called residual dipolar couplings (RDCs), can make a significant contribution towards determining the constitution of chemical compounds when traditional methods fail. To do this they embedded molecules of the compound in a gel which slightly constricts their mobility. By stretching the gel, the molecules can be aligned along a preferred orientation. While residual dipolar couplings average out in solution, they become measurable in such partially aligned samples and provide valuable structural information that can be used to build a model of the molecule.
To test this new approach to chemical structure determination the scientists examined a molecule whose atomic composition was known, but not the precise connectivities of the individual atoms in the molecule. The molecule was obtained using a unique reaction, so there were no precedents for its structure. Classical methods of analysis failed because of the compactness of the molecule. In this particular case it was only possible to determine the structure by means of residual dipolar couplings, so that the newly acquired knowledge could be used to draw conclusions about the formation of the molecule – something that in the past could only be speculated about.
"This type of analysis will not be suitable for all structures in the future," said scientists Luy and Kirsch. "There will still be molecules whose structures will defy all attempts at unraveling, in spite of tremendous efforts and cutting-edge technologies. But this new method provides us with one further tool to help us unravel the structural mysteries of nature."
INFORMATION:
This research was funded through the German Research Foundation DFG (Heisenberg Program, Research Group FOR 934) and the Chemical Industry Fund. The scientists conducted their measurements on equipment from the Bavarian NMR Center.
Literature:
Grit Kummerlöwe, Benedikt Crone; Manuel Kretschmer, Stefan F. Kirsch und Burkhard Luy: Residual Dipolar Couplings as a Powerful Tool for Constitutional Analysis: The Unexpected Formation of Tricyclic Compounds. Angewandte Chemie International Edition, scheduled to go online 17 or 18 February 2011. DOI: 10.1002/anie.2010007305
END
ELSE PRESS RELEASES FROM THIS DATE:
2011-02-18
Depending on the level of smoking and leisure time exercise, vitamin E supplementation may decrease or increase, or may have no effect, on the risk of pneumonia, according to a study published in Clinical Epidemiology.
In laboratory studies, vitamin E has influenced the immune system. In several animal studies vitamin E protected against viral and bacterial infections. However, the importance of vitamin E on human infections is not known.
Dr. Harri Hemila and Professor Jaakko Kaprio, of the University of Helsinki, Finland, studied the effect of vitamin E on the risk ...
2011-02-18
CHICAGO—Afraid of becoming disabled in old age, not being able to dress yourself or walk up and down the stairs? Staying physically active before symptoms set in could help. But so could going out to eat, playing bingo and taking overnight trips.
According to research conducted at Rush University Medical Center, higher levels of social activity are associated with a decreased risk of becoming disabled. The study has just been posted online and will be published in the April issue of the Journal of Gerontology: Medical Sciences.
"Social activity has long been recognized ...
2011-02-18
Feb. 17, 2011– A new treatment approach which uses tiny bursts of electricity to reawaken paralyzed muscles "significantly" reduced disability and improved grasping in people with incomplete spinal cord injuries, beyond the effects of standard therapy, newly published research shows.
In a study published online in the journal Neurorehabilitation and Neural Repair, Toronto researchers report that functional electrical stimulation (FES) therapy worked better than conventional occupational therapy alone to increase patients' ability to pick up and hold objects.
FES therapy ...
2011-02-18
WASHINGTON – Lifestyle changes—such as getting more exercise, time in nature, or helping others—can be as effective as drugs or counseling to treat an array of mental illnesses, according to a new paper published by the American Psychological Association.
Multiple mental health conditions, including depression and anxiety, can be treated with certain lifestyle changes as successfully as diseases such as diabetes and obesity, according to Roger Walsh, M.D., PhD. of the University of California, Irvine's College of Medicine. Walsh reviewed research on the effects of what ...
2011-02-18
VIDEO:
Although, in the majority of cases, the localized presence of Neisseria meningitidis in the throat has no consequence, it can sometimes lead to meningitis or septicaemia. The seriousness of these...
Click here for more information.
Although, in the majority of cases, the localized presence of Neisseria meningitidis in the throat has no consequence, it can sometimes lead to meningitis or septicaemia. The seriousness of these two infections is driving researchers from ...
2011-02-18
Young children living in urban public housing spend more time playing outdoors than other urban children, according to researchers at Rice University, Columbia University and Princeton University.
Contrary to the expectations of the researchers, who hypothesized that children living in poorer circumstances would be playing outside less, the study found that 5-year-olds living in public housing played outside 13 percent more per day, on average, than did other urban 5-year-olds. Children living in places of high physical disorder -- areas with visible graffiti, trash, ...
2011-02-18
The research could eventually lead to new approaches for controlling sleeping sickness in humans and wasting diseases in livestock which are caused by trypanosomes carried by the bloodsucking tsetse fly.
Biologists believe that sexual reproduction evolved very early and is now ubiquitous in organisms with complex cell structure (the eukaryotes, essentially all living organisms except bacteria). However, real evidence is lacking for a large section of the evolutionary tree.
Trypanosomes represent an early and very distant branch of the eukaryote tree of life and ...
2011-02-18
Scientists at The Wistar Institute and the University of Pennsylvania School of Medicine report the discovery of protein markers that could provide physicians with the first reliable blood test to predict ectopic pregnancies. Their findings are presented in the February 16 issue of the Journal of Proteome Research, currently available online. In a related small-scale study of clinical samples, published recently in the journal Fertility and Sterility, the researchers found that one of the proteins—ADAM12—showed a nearly 97 percent correlation with ectopic pregnancy.
Ectopic ...
2011-02-18
Champaign, IL – February 4, 2011 - An article in the current issue of Global Change Biology Bioenergy reviews the suitability of Agave as a bioenergy feedstock that can sustain high productivity in spite of poor soil and stressful climatic conditions accompanying climate change.
Agave, which grows successfully under hot, dry conditions, is currently used in the production of beverages, food, and fiber, and has only recently been considered a promising source of biofuel.
Garcia-Moya and colleagues (2011) were able to assess Agave's potential as a biomass crop by reviewing ...
2011-02-18
U.S. military officials should improve efforts to identify those at-risk and improve both the quality and access to behavioral health treatment in response to a sharp rise in suicide among members of nation's armed forces, according to a new RAND Corporation study.
Needed changes include making service members aware of the advantages of using behavioral health care, ensuring that providers and chaplains are delivering high quality care, and assuring that service members can receive confidential help for their problems, according to the report.
"Efforts should focus ...
LAST 30 PRESS RELEASES:
[Press-News.org] Residual dipolar couplings unveil structure of small molecules
New method for unraveling molecular structures
