Influence of charge repulsion on binding strengths: experimental and computational characterization of mixed alkali metal complexes of decamethylcucurbit[5]uril in the gas phase

摘要

Theory and experiment demonstrate that Coulombic repulsion plays a dominant role in the strength of binding a second cation to a rigid, ditopic host. Allosterism can be broadly defined as the influence binding a guest in one binding site has on binding in another site. This can involve enhanced binding of the second guest (positive allosterism) or reduced binding (negative allosterism). Herein we examine one of the simplest possible cases of negative allosterism, repulsion of one charged guest by another charged guest in another site.