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 analysi s of these systems in water yield a surprisingly uniform value of 5+/- 1 kJ per Mol and salt bridge. Additional contributions from hydrogen b ond and Van der Waals effects with the amino- cyclodextrins lead for n ucleotides 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 e lectron donor numbers for the different ligand atoms; the use of addit ive increments leads to a comprehensive description of corresponding a lkali and ammonium ion complex stabilities.