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Reports from University of Helsinki Describe Recent Advances in Nuclear Magnetic Resonance (Characteristic Spectral Patterns in the Carbon-13 Nuclear...

August 1, 2014



Reports from University of Helsinki Describe Recent Advances in Nuclear Magnetic Resonance (Characteristic Spectral Patterns in the Carbon-13 Nuclear Magnetic Resonance Spectra of Hexagonal and Crenellated Graphene Fragments)

By a News Reporter-Staff News Editor at Health & Medicine Week -- A new study on Nuclear Magnetic Resonance is now available. According to news reporting originating in Helsinki, Finland, by NewsRx journalists, research stated, "Nuclear magnetic resonance (NMR) spectroscopy is an important molecular characterisation method that may aid the synthesis and production of graphenes, especially the molecularscale graphene nanoislands that have gathered significant attention due to their potential electronic and optical applications. Herein, carbon-13 NMR chemical shifts were calculated using density functional theory methods for finite, increasing-size fragments of graphene, hydrogenated graphene (graphane) and fluorinated graphene (fluorographene)."

The news reporters obtained a quote from the research from the University of Helsinki, "Both concentric hexagon-shaped (zigzag boundary) and crenellated (armchair) fragments were investigated to gain information on the effect of different types of flake boundaries. Convergence trends of the C-13 chemical shift with respect to increasing fragment size and the boundary effects were found and rationalised in terms of low-lying electronically excited states. The results predict characteristic behaviour in the C-13 NMR spectra. Particular attention was paid to the features of the signals arising from the central carbon atoms of the fragments, for graphene and crenellated graphene on the one hand and graphane and fluorographene on the other hand, to aid the interpretation of the overall spectral characteristics. In graphene, the central nuclei become more shielded as the system size increases whereas the opposite behaviour is observed for graphane and fluorographene. The C-13 signals from some of the perimeter nuclei of the crenellated fragments obtain smaller and larger chemical shift values than central nuclei for graphene and graphane/fluorographene, respectively. The diameter of the graphenic quantum dots with zigzag boundary correlates well with the predicted carbon-13 chemical shift range, thus enabling estimation of the size of the system by NMR spectroscopy."

According to the news reporters, the research concluded: "The results provide data of predictive quality for future NMR analysis of the graphene nanoflake materials."

For more information on this research see: Characteristic Spectral Patterns in the Carbon-13 Nuclear Magnetic Resonance Spectra of Hexagonal and Crenellated Graphene Fragments. Chemphyschem, 2014;15(9):1799-1808. Chemphyschem can be contacted at: Wiley-V C H Verlag Gmbh, Boschstrasse 12, D-69469 Weinheim, Germany. (Wiley-Blackwell - www.wiley.com/; Chemphyschem - onlinelibrary.wiley.com/journal/10.1002/(ISSN)1439-7641)

Our news correspondents report that additional information may be obtained by contacting N. Ozcan, University of Helsinki, Dept. of Chem, Helsinki 00014, Finland. Additional authors for this research include J. Vahakangas, P. Lantto and J. Vaara (see also Nuclear Magnetic Resonance).

Keywords for this news article include: Helsinki, Finland, Europe, Nuclear Magnetic Resonance

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Health & Medicine Week


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