The dinuclear (Fe
II, Gd
III) complexes studied in this report derive from hexadentate Schiff base ligands abbre
viatedH
2L
i (
i = 1, 2, 3). H
2L
1 =
N,
N'-bis(3-methoxysalicylidene)-1,3-diamino-2,2'-dimethyl-propane, H
2L
2 =
N,
N'-bis(3-methoxysalicylidene)-1,2-diamino-2-methylpropane, and H
2L
3 =
N,
N'-bis(3-methoxysalicylidene)-1,2-diaminoethane.The crystal and molecular structures of three complexes have been determined at 160 K. Depending on the solventused in the preparation, L
1Fe(CH
3OH)Gd(NO
3)
3(CH
3OH)
2,
1, or L
1Fe((CH
3)
2CO)Gd(NO
3)
3,
1', is obtained from H
2L
1.A similar complex, L
2Fe((CH
3)
2CO)Gd(NO
3)
3,
2, is obtained from H
2L
2. Complex
1 crystallizes in the orthorhombicspace group
Pca2
1 (No. 29):
a = 22.141(3) Å,
b = 9.4159(16) Å,
c = 15.2075(17) Å,
V = 3170.4(7) Å
3,
Z =4. Complexes
1' and
2 crystallize in the monoclinic space group
P2
1/
c (No. 14):
1',
a = 9.6264(17) Å,
b =19.662(3) Å,
c = 16.039(3) Å,
![](/images/gifchars/beta2.gif)
= 95.15(2)
![](/images/entities/deg.gif)
,
V = 3023.6(9) Å
3,
Z = 4;
2,
a = 9.7821(13) Å,
b = 18.7725(17)Å,
c = 16.100(2) Å,
![](/images/gifchars/beta2.gif)
= 96.497(16)
![](/images/entities/deg.gif)
,
V = 2937.5(6) Å
3,
Z = 4. Complexes
1,
1', and
2 possess an Fe(O
phenoxo)
2Gd core. The mononuclear L
3Fe complex could be prepared from H
2L
3 but not the related dinuclear (Fe, Gd)species. Mössbauer spectroscopy e
vidences that the iron center is in the +2 oxidation state for the six complexes.The experimental magnetic susceptibility and magnetization data of complexes
1,
1', and
2 indicate the occurrenceof weak Fe
II-Gd
III ferromagnetic interactions. Single ion zero-field splitting of the iron(II) must be taken into accountfor satisfactorily fitting the data by exact calculation of the energy levels associated to the spin Hamiltonian throughdiagonalization of the full matrix for axial symmetry (
1,
J = 0.50 cm
-1,
D = 2.06 cm
-1;
1',
J = 0.41 cm
-1,
D =3.22 cm
-1;
2,
J = 0.08 cm
-1,
D = 4.43 cm
-1).