The LCuGd(NO3)3·Me2CO complex crystallizes in the monoclinic space group P21/c (No. 14) in a cell having the dimensions a = 9.799(1) Å, b = 18.926(3) Å, c = 16.012(1) Å, β = 96.530(8)°, Z = 4. The four units forming the unit cell do not display any obvious short contacts between them. The magnetic behavior is characteristic of a ferromagnetic interaction between the Gd3+ and Cu2+ ions.

The reaction of {2,2'-[1-methyl-1,2-propanediyl bis(nitrilomethylidyne]-di(6-methoxyphenolato)}copper-(ii) (LCu) or nickel(ii) (LNi) with Ln(NO 3 ) 3 in acetone led to strictly heterodinuclear [LCu(Me 2 CO)Ln-(NO 3 ) 3 ] and [LNi(Me 2 CO)Ln(NO 3 ) 3 ] complexes (with Ln all the lanthanides except prometheum; Ni in the low-spin state). Three complexes [(Cu 2 , Ce 3 ), (Cu 2 , Yb 3 ) and (Ni 2 , Dy 3 )] have been structurally characterized. They crystallize in the same monoclinic spacegroups P2 1 /c (no. 14) and are isomorphous. This relationship in conjunction with the diamagnetism of the Ni 2 ion allow an empirical evaluation of the effect of the crystal field on the magnetic properties as well as an approach towards the nature of the coupling between the copper(ii) and the lanthani-de(iii) ions in the [LCu(Me 2 CO)Ln-(NO 3 ) 3 ] complexes. The Cu ± Ln interaction is antiferromagnetic for Ln Ce, Nd, Sm, Tm, and Yb, and ferromagnetic for Ln Gd, Tb, Dy, Ho, and Er; however, the Cu ± Pr and the Cu ± Eu pairs are devoid of any significant interaction along with the Cu ± La and Cu ± Lu pairs, in accordance with the nonmagnetic nature of the ground state for these lanthanide ions.

Starting from a single precursor, bis(3-methoxysalicylaldehydato)copper (II), which contains an O(4)Cu chromophore, three routes to discrete dinuclear Cu(II)/Ln(III) complexes (Ln = Pr, Eu, Gd, Yb) are described. The pairs of chromophores occurring in the resulting complexes are either O(4)Cu/O(4)Ln or O(2)N(2)Cu/O(4)Ln, the coordination sphere of the Ln ions being completed, in both cases, with six oxygen atoms afforded by three nitrato ions. Two Cu/Gd complexes involving either two tridentate ligands (2) or one hexadentate ligand (7) have been structurally characterized. They crystallize in the monoclinic space groups P2(1)/n (No. 14) (2) and P2(1)/c (No. 14) (7). The cell parameters are a = 9.7185(7) Å, b = 16.7839(12) Å, c = 14.8868(8) Å, beta = 97.445(5) degrees, and Z = 4 (2) and a = 9.7656(9) Å, b = 19.889(2) Å, c = 15.870(2) Å, beta = 95.512(9) degrees, and Z = 4 (7) respectively. The magnetic properties of six Cu/Ln complexes have been determined. A quantitative analysis of the magnetic properties of the Cu/Gd complexes shows that the interaction is of the ferromagnetic type with a J constant varying from 4.8 to 7.0 cm(-)(1). The decrease of the interaction parallels the variation of the dihedral angle between the two halves (OCuO and OGdO) of the bridging core.

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A structural determination confirms that the tripodal ligand tris[4-(2-hydroxy-3-methoxyphenyl)-3-aza-3-butenyl]amine (LH3) offers two coordination sites, an inner N4O3 one and an outer O6 one, in which two identical or different lanthanide ions can be successively encapsulated, thus providing access to a general route for the preparation of homo- and heterodinuclear complexes.

The structural determination of a dinuclear Gd(III)−Ni(II) entity confirms the strict dinuclearity of the complex while the magnetic properties evidence the presence of a ferromagnetic interaction between the paramagnetic (S = 1) nickel ion and the gadolinium center (S = 7/2), with a J value of 3.6 cm-1.

Two original dinuclear (Cu(II),Gd(III)) complexes (1 and 2) deriving from polydentate nonsymmetrical Schiff base ligands LiH2 have been prepared. Formally they differ by the length of the diamino chain. They crystallize in the orthorhombic Pbca (No. 61) (1) and in the monoclinic P2(1/n) (No. 14) (2) space groups. The cell parameters are a = 12.6295(7) A, b = 20.7894(9) A, c = 18.3301(13) A, and Z = 8 for 1 and a = 12.7246(16) A, b = 13.5691(17) A, c = 14.5310(19) A, beta = 94.629(16) degrees , and Z = 4 for 2. These structural studies show that in both complexes the CuII and GdIII ions are doubly bridged by a phenolato oxygen atom and an oximato (N-O) pair. The bridging network is not planar. The more important distortions are observed for the complex having the larger diamino chain. Unexpectedly the latter complex presents an antiferromagnetic interaction, but the related J value is small (J approximately equal to -0.49 cm(-1)). In the former complex the interaction is ferromagnetic (J approximately equal to 3.5 cm(-1)) as it is for complexes containing (CuO2Gd) bridging cores which yield J values varying from 1.4 to 10.1 cm(-1).

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