YTTRIUM(III) AND LANTHANUM(III) COMPLEXES OF A 15-MEMBERED MACROCYCLEWITH 3 PENDANT CARBOXYMETHYL GROUPS

The yttrium(III) and lanthanum(III) complexes of 4,7,10,13-pentaaza-1, 4,7-cyclopentadecanetriacetic acid, namely, yclo-pentadecanetriacetato -O1,O4:O7)diyttrium(III) tetradecahydrate [Y2(C16H24N5O8)2(H2O)2].14H2 O, and lopentadecanetriacetato-O1,O4:-O7)dilanthanum(III) tetradecahyd rate, [La2(C16-H24N5O8)2(H2O)2].14H2O, have a binuclear structure in w hich two metal ions are located between two macrocycles. The coordinat ion geometry around each metal ion is distorted tricapped trigonal pri smatic. The geometrical properties are defined by the inflexible confo rmation of the macrocycle and the strong coordination of the O atoms.