In thermodynamics, enthalpic is a term referring to properties of enthalpy.

In 2006, David Baker, gave the following use, as an example: [1]

“For covalent bonds, entropic effects are often of secondary interest because the enthalpic bond energy contributes to free energy for outweigh the entropic contributions under ambient thermal conditions. For H-bonding, this is not the case. H-bonding principles must therefore be formulated with due regard for the importance of both enthalpic and entropic factors, judiciously balanced in a T-dependent manner.”

The term “enthalpic force” is another variant. On the logic that affinity is the driving force of a chemical reaction or process, the thermodynamic theory of affinity, situates the view that affinity is comprised of an entropic force (TΔS) and an “enthalpic force” (– ΔH), whose influence varies as temperature varies. This gives rise to concepts such as enthalpy-entropy compensation effects, among others.

Transition state
The classic model of reaction mechanism between two reactants A and B is as follows :

A+ B
A ∙∙∙ B
A – B
close proximity

encounter complex

The two middle steps are often characterized by enthalpic energy barriers

The last step of the binding process is the latter stage transition from the favorable intermediates to the bound state unit AB, being a process of induced fit, limited by a rate constant, which requires structural rearrangements, which is assumed to be a process of "overcoming mostly enthalpic energy barriers".

1. Baker, David. (2006). Peptide Solvation and H-bonds (section V: General Enthalpic and Entropy Principles of H-Bonding, pgs. 141-). Academic Press.

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