Positional Isomerism and Stereoisomerism

Positional isomerism is a geometric factor of obvious significance in lipophilicity. In fact, it may be convenient to distinguish between regioisomerism and tautomerism  

Stereoisomerism is another geometric factor having obvious significance for lipophilicity. Again, it is convenient to distinguish between diastereoisomerism and conformational isomerism. 

The possibility for a solute to exist in neutral or charged states obviously has a major impact on its partitioning behavior. First, a charged group will contribute a marked drop in lipophilicity. And second, ionization will dramatically alter intramolecular interactions. Thus, ionization will affect electronic 

---