SOLID-STATE AND SOLUTION STUDY OF TRINUCLEAR (NI,BA,NI) COMPLEXES - (L(2)(1)NI)(2)BA(CLO4)(2)CENTER-DOT-2H(2)O (1) AND (L(2)(2)NI)(2)BA(CLO4)(2)CENTER-DOT-2H(2)O (2) (L(1)=3-METHOXYSALICYLALDIMINATO AND L(2)=3-(2-METHOXYETHXY)SALICYLALDIMINATO) - CRYSTAL AND MOLECULAR-STRUCTURE OF 2

The nickel(II) complexes of L(1) = 3-methoxysalicylaldiminato and L(2) = 3-(2-methoxyethoxy)s alicylaldiminato react with barium ions to aff ord bimetallic complexes characterized by a Ba to Ni ratio of 1/2. A s tructural determination of the complex (L(2)(2)Ni)(2)Ba(ClO4)(2) . 2H( 2)O (2) shows that it crystallizes in the orthorhombic space group Pbc a (No. 61) with 8 formula units in the cell having the dimensions a = 14.780(1) Angstrom, b = 24.888(2) Angstrom, and c = 27.291(2) Angstrom . In the presence of barium ions, the precursor complexes L(2)(1)Ni an d L(2)(2)Ni change their configurations from trans to cis so as to off er a polyoxygenated coordination site to a barium ion and assemble the mselves around that ion to yield bimetallic species. Structural analog ies with the polyether complexes of barium are discussed. Solution stu dies point to a great sensitivity of 2 to the nature of the solvent, c ontrary to (L(2)(1)Ni)(2)Ba(ClO4)(2) . 2H(2)O (1). Indeed, an importan t dissociation is induced by solvents which display good donor propert ies and which are able to stabilize the barium ions via solvation.