Energetic vs synergetic stability: A theoretical study

Abstract

The aim of this manuscript is to define a new concept, namely synergetic stability, which can be useful in systems where the interplay of noncovalent interactions is important. Usually, the stability of a noncovalent complex is related to the complexation energy, which is directly proportional to the strength of the noncovalent interactions that are involved in the complex. In ternary complexes characterized by the presence of two different noncovalent interactions, three situations regarding the variation of the strength of the interactions (in comparison to the binary complexes) can be present. The coexistence of the interactions causes, first a strengthening of both interactions, second, a weakening of both, and, third, a strengthening of one interaction at expenses of the weakening of the other. This study deals with ternary complexes where ion-π and either hydrogen bonding, dihydrogen bonding, or halogen bonding interactions coexist. © 2009 American Chemical Society.