OXOPHILY OF GADOLINIUM(III) AND SYNTHESIS OF DISSYMMETRIC DI(SCHIFF BASES) AND DISSYMMETRIC DINUCLEAR COMPOUNDS - CRYSTAL-STRUCTURE OF [CU2L'(OH)](CLO4)2.H2O WITH L'= 2-[N-(2-PYRIDYLETHYL)FORMIMIDOYL]-6-[N-((DIMETHYLAMINO)PROPYL)FORMIMIDOYL]PHENOLATO

The strong oxophilic character of the Gd(III) ion has been utilized to protect one of the carbonyl functions of 2,6-diformyl-4-methylphenol, which has allowed to synthesize quantitatively mono(Schiff bases), then dissymmetric di(Schiff bases). The synthetic process is as follows: the reaction of 2,6-diformyl-4-methylphenol with a primary amine RNH2 in the presence of Gd(III) affords a complex in which Gd(III) is coordinated to two mono(Schiff bases) through their carbonyl and phenolic oxygen atoms. The mono(Schiff base) may be isolated by precipitation of Gd(III) in the form of gadolinium(III) oxalate. The reaction of another primary amine, R'NH2, on this mono(Schiff base) affords a dissymmetric di(Schiff base), from which dissymmetric dinuclear compounds can be synthesized. For example, this reaction has been carried out with RNH2 = 2-(2-aminoethyl)pyridine and R'NH2 = NN-dimethylpropylenediamine. The mono(Schiff base) 2-formyl-6-(N-(2-pyridylethyl)formimidoyl)-4-methylphenol (HL) and the di(Schiff base) 2-[N-(2-pyridylethyl)formimidoyl]-6-[N-((dimethylamino)propyl)formimidoyl]-4-methylphenol (HL') have been unambiguously characterized from their H-1 NMR spectra. The copper(II) dinuclear compound [CuL'(OH)](ClO4)2-H2O obtained from this di(Schiff base) has been synthesized, and its crystal structure has been solved. This compound crystallizes in the monoclinic system, space group P2(1)/n. The lattice parameters are a = 13.439(10) angstrom, b = 14.153(6) angstrom, c = 14.734(13) angstrom, beta = 92.73(7)-degrees, and Z = 4.