STRUCTURES OF THE YTTRIUM COMPLEXES OF 1,4,7,10-TETRAAZACYCLODODECANE-N,N',N'',N'''-TETRAACETIC ACID (H-4 DOTA) AND N,N''-BIS(BENZYLCARBAMOYLMETHYL)DIETHYLENE-TRIAMINE-N,N',N''-TRIACETIC ACID AND THE SOLUTION STRUCTURE OF A ZIRCONIUM COMPLEX OF H-4 DOTA

The solid-state crystal structure of Na[Y(dota)(H2O)].4H2O (H-4dota = 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) at 11 5 K has been obtained together with the solution structure of the neutral zirconium complex. The yttrium complex shows a mono-capped (H2O) square-antiprismatic structure while the solution H-1 NMR spectra of [Zr(dota)(HO)] suggest that a structure of lower symmetry is adopted and a minor isomer is observed. The crystal structure of the yttrium complex of N,N'-bis(benzylcarbamoylmethyl)diethylenetriamine-N,N',N''-triacetic acid has revealed amide carbonyl ligation in a distorted mono-capped square-antiprismatic structure, with one metal-bound water molecule.