Macrobicyclic ligands for use in MRI

4 Title: Macrobicyclic ligands for use in MRI Author: Bc. Miroslav Pniok Department: Department of Inorganic Chemistry, Faculty of Science Supervisor: doc. RNDr. Jan Kotek, Ph.D. Supervisor's e-mail address: modrej@natur.cuni.cz Abstract: The aim of this project is to synthesize new kind of macrobicyclic ligands for Ln3+ ions, especially Gd3+ ion. Gadolinium(III) complexes are widely used in the clinical practice as contrast agents for MR imaging and an improvement of their properties is in the center of interest of many scientific teams. The macrobicyclic ligands have been designed to make possible coordination of two water molecules in the first coordination sphere with fast water exchange. The macrocyclic core (cyclen) is combined with a linking phosphinate chain in N1 ,N4 - and N1 ,N7 -positions forming a cryptand-like structure. The N1 ,N7 -isomer Et2L1 was synthesized in a small amount so only the N1 ,N4 -isomer H2L3 has been studied. The protonation constants have been determined by pH 31 P NMR titration. Keywords: cyclen, chelating agent, cryptand, MRI, phosphinat