BULKY ORTHO 3-METHOXY GROUPS ON N4O3 AMINE PHENOL LIGANDS PRODUCING 6-COORDINATE BIS(LIGAND)LANTHANIDE COMPLEX CATIONS 3L)2]3-HYDROXY-3-METHOXYBENZYL)AMINO)ETHYL)AMINE)( (LN = PR, GD H3L = TRIS(((2)

The synthesis and characterization of an N4O3 amine phenol ris(((2-hyd roxy-3-methoxybenzyl)amino)ethyl)amine, H3L4) and its lanthanide compl exes [Ln(H3LA)(NO3)3] (Ln = Pr, Nd) and [Ln(H3L4)2](NO3)3 (Ln = Pr, Nd , Gd, Yb) are reported. The N4O3 amine phenol ligand is the KBH4 reduc tion product of the Schiff base derived from the reaction of tris(2-am inoethyl)amine (tren) and 3 equiv of o-vanillin. The reactions of lant hanide nitrates with 1 equiv of H3L4 produce nine-coordinate type II c omplexes, [Ln(H3L4)(NO3)3] (Ln = Pr, Nd), in which H3L4 acts as a trid entate O3 ligand and six-coordinate bis(ligand) type IV complexes, [Ln (H3L4)2](NO3)3 (Ln = Gd, Yb). The latter were prepared from the reacti ons of lanthanide nitrates with 2 equiv of H3L4 in the presence of sod ium hydroxide. The X-ray crystal structures of [Ln(H3L4)2](NO3)3.xH2O. YMeOH (Ln = Pr, x = 5.56, y = 0.44; Ln = Gd, x = 5.96, y = 0.66) have been determined. Crystals of [Ln(H3L4)2](NO3)3.xH2O.yMeOH (Ln = Pr, x = 5.56, y = 0.44; Ln = Gd, x = 5.96, y = 0.66) are isomorphous, crysta llizing in the monoclinic space group C2/c, with a = 25.260(2) [25.131 (2)] angstrom, b = 14.927(3) [14.990(4)] angstrom, c = 21.402(2) [21.4 59(3)] angstrom, beta = 112.912(7)-degrees [112.615(7)-degrees], Z = 4 , and V = 7433(2) [7462(2)] angstrom3 (bracketed values refer to the G d complex). The structures were solved by the Patterson method and wer e refined by full-matrix least-squares procedures to R = 0.033 [0.033] and R(w) = 0.040 [0.0361 for 5032 [58671 reflections with I greater-t han-or-equal-to 3sigma(I), respectively. In both complexes, the three phenolate O atoms of each of the two tridentate amine phenol ligands c oordinate to the metal ions in a slightly distorted octahedral geometr y while the secondary amine N atoms are protonated and uncoordinated. The effects of bulky 3-methoxy groups of the phenyl rings on the coord inating behavior toward lanthanide metals are discussed.