Preferred Label : strain energy;
IUPAC definition : The excess energy due to steric strain of a molecular entity or transition state structure,
i i.e. /i distortions relative to a reference (real or hypothetical) 'strainless'
structure with the standard bond lengths, bond angles and dihedral angles. The strain
energy components involve the following destabilizing terms: non-bonded repulsions,
bond-angle distortions, bond stretch or compression, rotation around or twisting of
double bonds, and electrostatic strain. In general, the contributions of these components
are inseparable and interdependent. A quantitative assessment of strain and strain
energies can be made by taking the difference between the heat of formation of the
substance under consideration and that of a hypothetical strain-free model. Several
approaches to the assessment of strain energies have been developed based on the use
of energies of isodesmic and homodesmotic reactions and on the so-called 'strainless
increments', i i.e. /i heats of formation of certain groups (CH sub 3 /sub , CH
sub 2 /sub , CH, C i etc /i ).;
Origin ID : ST07108;
See also
The excess energy due to steric strain of a molecular entity or transition state structure,
i i.e. /i distortions relative to a reference (real or hypothetical) 'strainless'
structure with the standard bond lengths, bond angles and dihedral angles. The strain
energy components involve the following destabilizing terms: non-bonded repulsions,
bond-angle distortions, bond stretch or compression, rotation around or twisting of
double bonds, and electrostatic strain. In general, the contributions of these components
are inseparable and interdependent. A quantitative assessment of strain and strain
energies can be made by taking the difference between the heat of formation of the
substance under consideration and that of a hypothetical strain-free model. Several
approaches to the assessment of strain energies have been developed based on the use
of energies of isodesmic and homodesmotic reactions and on the so-called 'strainless
increments', i i.e. /i heats of formation of certain groups (CH sub 3 /sub , CH
sub 2 /sub , CH, C i etc /i ).
