Solvation-desolvation balance

The solvation-desolvation balance may be favorable or unfavorable for binding. 

Electrostatic interactions are considered to be important attractive forces, due to their relative strength, [59, 116—119]. The molecular electrostatic field which surrounds a binding site guides the correct orientation of the drug [59] and is responsible for the first contact. However, the role of electrostatic interactions as being mainly responsible for high affinity has been questioned due to an often unfavorable solvation-desolvation energy balance. It is difficult to express their contribution in a quantitative manner, due to a number of reasons ... 

There are unusual hazards associated with partial desolvation of crystalline solvated oxosalts, notably perchlorates. This may be because desolvation causes the oxygen balance to approach the zero balance point and maximum energy release potential. A similar effect has also been seen with an hydrated salt. 

A possible explanation of the reduced stability of the lower organic solvates may be connected with the effect of reduced solvation upon the oxygen balance of the salts. Uncolvated metal perchlorates have an apparent balance of +700%, and solvation with 4 mols of acetonitrile reduces this to -46.3%, and with 4 or 6 mols of DMSO to —43% and —28.6% respectively. Desolvation to 2.18 mols of acetonitrile, or to 2.0 mols of DMSO, would give products of zero oxygen balance, with maximum energy release potential [8],... 

---