ELECTROSTATICS IN MOLECULAR RECOGNITION - FROM ION-PAIRS AND INOPHORES TO NUCLEOTIDES AND DNA

The practical use as well as the empirical evaluation of electrostatic contributions in supramolecular complexes is reviewed on the basis of organic ion pairs, including amino-cyclodextrin - phosphate complexes and interactions between polyamines and DNA. The systematical analysis of these systems in water yield a surprisingly uniform value of 5+/-1 kJ per Mol and salt bridge. Additional contributions from hydrogen bond and Van der Waals effects with the amino- cyclodextrins lead for nucleotides to simultaneous discrimination between nucleobases, 3'-/5'- phosphates, and 2'-oxy/deoxy derivatives. Electrostatic interactions in crown ether and cryptand complexes can be scaled by corresponding electron donor numbers for the different ligand atoms; the use of additive increments leads to a comprehensive description of corresponding alkali and ammonium ion complex stabilities.