ZACYCLOTETRACOSANE-1,4,7,10,13,16,19,22-OCTAACETIC ACID (H(8)OTEC) AND AZACYCLOHEXACOSANE-1,4,7,10,14,17,20,23-OCTAACETIC ACID (H(8)OHEC) -SYNTHESIS AND CHARACTERIZATION OF 2 LARGE MACROCYCLIC POLYAMINE POLYCARBOXYLIC LIGANDS AND SOME OF THEIR COPPER(II) AND LANTHANIDE(III) COMPLEXES

The optimized synthesis of two new macrocyclic polyamine polycarboxyli c Ligands, azacyclohexacosane-1,4,7,10,14,17,20,23-octaacetic acid (H( 8)OHEC) (10) and zacyclotetracosane-1,4,7,10,13,16,19,22-octaacetic ac id (H(8)OTEC) (12), is presented. The key step in the synthesis of bot h is the high yield carboxymethylation of the corresponding macrocycli c amines using tert-butyl bromoacetate followed by acidic hydrolysis o f the acetate protecting groups. The molecular structures of the inter mediates 1,4,7,10,14,17,20,23-octaazacyclohexacosane (OHEC-amine) (8), and octa-tert-butyl ,16,19,22-octaazacyclotetracosane-1,4,7,10,13,16, 1 (OTEC-ester) (11) are determined by X-ray crystal structure analysis . OHEC-amine 8 reacts with 2 equiv, of CuSO4 yielding the dinuclear co mplex [Cu-2(OHEC-amine)](SO4)(2) (13). Complex 13 crystallizes with 16 molecules of water. 13 . 16 H2O contains two copper atoms, which are coordinated in a strongly distorted octahedral fashion by four nitroge n atoms, one oxygen atom from the sulfate dianion and one oxygen atom from a water molecule. The new ligands 10 and 12 are fully characteriz ed by 1D- and 2D-NMR spectroscopy. Both Ligands form dinuclear lanthan ide(III) chelates (Ln = Y, Sm, Eu, Gd, Yb, Lu), which are stable and h ighly water soluble. With lanthanum(III) only mononuclear complexes ar e formed.