Qualitative comparison between the quantum calculations and electrospray mass spectra of complexes of polyammonium macrotricyclic ligands with dicarboxylic acids

The host-guest interactions play a very important robe in chemical and biol ogical processes. It is therefore important to be able to characterize thes e complexes. Electrospray mass spectrometry can be used to characterize the complex formation. It provides information on the mass and the charge of t hese ionic complexes. In this article, we show that the use of ab initio an d semiempirical calculations, in addition to the results obtained by electr ospray mass spectrometry, reveal to be a promising tool for the study of th ese noncovalent complexes. In this article, host-guest complexes formed by macropolycyclic polyammonium host molecules and dicarboxylic acids are stud ied. (C) 2001 American Society for Mass Spectrometry.