Crystal structure / Solution structure / Homodinuclear lanthanide complexes / Lanthanides / Macrocyclic ligands / Polyamine polycarboxylic acid
The solid-state structures of the four homodinuclear chelate ligand system with that of the parent amine and its dinuclear copper complex. NMR investigations of the diamagnetic complexes,
Na 2 (Eu 2 OHEC)-complex 1 indicate a very similar environment of the lanthanide cations in solution and in the solid state. Low-(H 2 O) 2 ] • 11 H 2 O (3), and [Cs 2 (La 2 OHEC)(H 2 O) 2 ] • 14 H 2 O (4) (H 8 OHEC = 1,4,7,10,14,17,20,23-octaazacyclohexacosane-temperature and variable-temperature 1 H-NMR measurements prove the existence of two isomers of 1 (3.5:1 1 ,4,7,10,14,17,20,23-octaacetic acid), were determined by Xray crystal structure analysis. Each lanthanide(III) ion is ratio) which undergo conformational processes. The rate constants of these processes were deduced from a complete ninefold coordinated by eight donor atoms of the ligand system and the oxygen atom of one water molecule. The line shape analysis and were used to determine the activation parameters. structures are compared with those of DOTA-and TETAcoordinated complexes and the conformation of the OHEC mational and coordination equilibria in aqueous solution [a]