Preferred Label : stereochemical non-rigidity;
IUPAC acronym : NMR;
IUPAC definition : The capability of a molecule to undergo fast and reversible intramolecular isomerization,
the energy barrier to which is lower than that allowing for the preparative isolation
of the individual isomers at room temperature. It is conventional to assign to the
sterochemically non-rigid systems those compounds whose molecules rearrange rapidly
enough to influence NMR line shapes at temperatures within the practical range (from
-100 C to 200 C) of experimentation. The energy barriers to thus defined rearrangements
fall into the range of 5–20 kcal/mol (21–85 kJ/mol).;
Origin ID : ST07107;
Automatic exact mappings (from CISMeF team)
- See also
The capability of a molecule to undergo fast and reversible intramolecular isomerization,
the energy barrier to which is lower than that allowing for the preparative isolation
of the individual isomers at room temperature. It is conventional to assign to the
sterochemically non-rigid systems those compounds whose molecules rearrange rapidly
enough to influence NMR line shapes at temperatures within the practical range (from
-100 C to 200 C) of experimentation. The energy barriers to thus defined rearrangements
fall into the range of 5–20 kcal/mol (21–85 kJ/mol).
