| Abstract |
A new bis(phenol)dimethyltetraazamacrocycle, 1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dimethyl-1,4,8,11-tetraa zacyclotetradecane (H-2\((PhO)-Ph-tBu2)(2)Me(2)Cyclam\) (1), is described. Deprotonation of 1 with sodium or potassium hydrides afforded Na-2\((PhO)-Ph-tBu2)(2)Me(2)Cyclam\ (2) and K-2\((PhO)-Ph-tBu2)Me(2)Cyclam\ (3), respectively. Reactions of 2 or 3 with yttrium or lanthanide trichlorides led to the formation of neutral rare earth metal complexes of general formula [\((PhO)-Ph-tBu2)(2)Me(2)Cyclam\LnCl] (Ln = Y (4), La (5), Sm (6), Yb (7)) in moderate to high yields. The molecular structures of 4-7 were determined by single-crystal X-ray diffraction analysis and reveal that the ligand s denticity depends on the size of the metal ions. The smaller Y3+ and Yb3+ lead to distorted octahedral geometries where the dianionic ligand acts as pentadentate, while the larger ions, La3+ and Sm3+, form capped trigonal prismatic complexes with the cyclam derivative acting as a hexadentate chelator. (C) 2012 Elsevier B.V. All rights reserved. |
