Stability investigations of medically relevant complexes by the simultaneous analysis of series of spectrophotometric titrations

This contribution presents a selection of results obtained using spectropho tometric titrations and subsequent second-order global analysis of the data . For several reasons the investigated equilibria present particular challe nges to traditional analysis techniques. Equilibrium constants and UV absor ption spectra for differently protonated ligand and complex species in the complexation of Eu3+ with PDA (1,10-phenanthroline-2,9-dicarboxylic acid) a nd with FNAC (4,4,4-trifluoro-1-(2'-naphthyl)-1,3-butanedione) are reported . Additionally, in order to investigate the stability of the complex betwee n In3+ and DTPA (diethylenetriamine-pentaacetic acid), the absorbing auxili ary ligand HEED (N,N'-di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid ) was employed in a ligand competition study. Equilibrium constants and UV absorption spectra are reported for HEED protonated species, and In(III)-HB ED and In(III)-DTPA complex species. (C) 1999 Elsevier Science Ltd. All rig hts reserved.