The 600 MHz 1H-1H COSY spectrum of
In ascending order, sections of the 125 MHz 13C NMR spectra of 9-(2-indenyl)triptycene, η6-Cr complex,
Indenyl- and alkene-rotations interconvert different pairs of alkene protons in
Symmetry 2014, 6(3), 622-654; doi:10.3390/sym6030622
School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland; E-Mail: email@example.com; Tel.: +353-1-716-2165; Fax: +353-1-716-1178
Alcan Award of the Canadian Society for Chemistry (2000)
For contact information in Dublin, see http://chemistry.ucd.ie/mcglinchey/
Variable-temperature NMR spectroscopy is probably the most convenient and sensitive technique to monitor changes in molecular structure in solution. Rearrangements that are rapid on the NMR time-scale exhibit simplified spectra, whereby non-equivalent nuclear environments yield time-averaged resonances. At lower temperatures, when the rate of exchange is sufficiently reduced, these degeneracies are split and the underlying “static” molecular symmetry, as seen by X-ray crystallography, becomes apparent. Frequently, however, such rearrangement processes are hidden, even when they become slow on the NMR time-scale, because the molecular point group remains unchanged. Judicious symmetry breaking, such as by substitution of a molecular fragment by a similar, but not identical moiety, or by the incorporation of potentially diastereotopic (chemically non-equivalent) nuclei, allows the elucidation of the kinetics and energetics of such processes. Examples are chosen that include a wide range of rotations, migrations and other rearrangements in organic, inorganic and organometallic chemistry.
Multiple Cope rearrangements equilibrate all ten CH positions in bullvalene.
Interconversions of the eight different indenyl ring environments in the
The photograph shows the group in May 2000 at a Chinese restaurant.
Standing: Mike McGlinchey, Nicole Deschamps, Andrea Szkurhan, John Kaldis, Hari Gupta.
Seated: Stacey Brydges, Pippa Lock, Nada Reginato, Laura Ennis.
Since the picture was taken, Frank Ogini has joined the group.
University College Dublin campus double-decker bus
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