Enhanced Chelate Cooperativity in Polar Solvents

摘要: High-throughput UV–vis titrations in combination with chemical double-mutant cycles (DMCs) have been used to study the competition of a polar solvent for formation intramolecular H-bonds. Twenty-four different zinc porphyrin–pyridine complexes were investigated mixtures toluene and phenol. DMCs determine effective molarities (EM) phenol–amide H-bonds as function composition. The values EM increase by an order magnitude increasing concentrations more solvent, Phenol solvates amide groups on ligands strongly, steric bulk destabilizing complexes. These adverse interactions are removed when formed therefore provide increased driving force cooperative interactions. result is that effects competitive solvents reduce binding affinity attenuated significant extent corresp...