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The steric strain between the two terminal methyl groups accounts for the difference in energy between the two similar, yet very different conformations ...
a torsion angle between 90° and 150° or −90° and −150° is called anticlinal (ac) a torsion angle between ±150° and 180° is called antiperiplanar (ap), also called anti-or trans-conformation; Torsional strain or "Pitzer strain" refers to resistance to twisting about a bond.
The activation strain model was originally proposed and has been extensively developed by Bickelhaupt and coworkers. [4] This model breaks the potential energy curve as a function of reaction coordinate, ζ, of a reaction into 2 components as shown in equation 1: the energy due to straining the original reactant molecules (∆E strain) and the energy due to interaction between reactant ...
These types of steric interactions are commonly known as 1,3 diaxial interactions. [2] These types of interactions are not present with substituents at the equatorial position. There are generally considered three principle contributions to the conformational free energy: [3] Baeyer strain, defined as the strain arising from deformation of bond ...
In a molecule, strain energy is released when the constituent atoms are allowed to rearrange themselves in a chemical reaction. [1] The external work done on an elastic member in causing it to distort from its unstressed state is transformed into strain energy which is a form of potential energy.
Steric hindrance is often exploited to control selectivity, such as slowing unwanted side-reactions. Steric hindrance between adjacent groups can also affect torsional bond angles. Steric hindrance is responsible for the observed shape of rotaxanes and the low rates of racemization of 2,2'-disubstituted biphenyl and binaphthyl derivatives.
A two-dimensional flow that, at the highlighted point, has only a strain rate component, with no mean velocity or rotational component. In continuum mechanics, the strain-rate tensor or rate-of-strain tensor is a physical quantity that describes the rate of change of the strain (i.e., the relative deformation) of a material in the neighborhood of a certain point, at a certain moment of time.
The definition of strain rate was first introduced in 1867 by American metallurgist Jade LeCocq, who defined it as "the rate at which strain occurs. It is the time rate of change of strain." In physics the strain rate is generally defined as the derivative of the strain with respect to time. Its precise definition depends on how strain is measured.