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The tetradentate copper (I1) Schiff base complexes CuHAPen and CuSALen react with Gd (C10) 4) 3 to yield crystalline of formula (CUHAP~~) ~G~ (H~O) ~ (C~O, ) (I~). anZdC U (HCAUPS~A~L ~~) ~G~ (H, O) ~ (C~O~) ~. ~CUSAL~~. 0. 5CzH5N02 (II), respectively. Their crystal structures were determined through X-ray diffraction at room temperature: I in the monoclinic system, space group C2/c with lattice constants a = 16. 092 (4) A, 6 = 31. 262 (6) A, c = 15. 249 (4) A, @ = 95. 44 (5) ’, with Z = 4; and I1 crystallizes in the monoclinic system, space group P2, /a with lattice constants a= 18. 333 (5) A, b = 33. 233 (7) A, c = 11. 864 (3) A, @ = 95. 94 (5) ’, with Z = 4. Least-squares refinement of the structure to a conventional R factor of 0. 059 (I) and 0. 061 (11). In both structures a tripositive ion, three perchlorate, and two copper base molecules are present. In the tripositive ion a central gadolinium (II1) is bound in a distorted pentagonal-bipyramidal to three water molecules and to four oxygen atoms of two copper (I1) Schiff base complexes. The temperature dependence the magnetic susceptibility of both I and I1 was investigated in the range 1. 2-300 K. The effective magnetic moments of compounds have been found to increase steadily on decreasing temperature. These data have been interpreted with use a Heisenberg spin Hamiltonian in the following form: 3f s J (S1. S2+ S2. S3) + J’S1. S3w, here 1 and 3 refer to copper (I1) and 2 refers to gadolinium. The least-squares fit of the experimental susceptibilities yielded g = 1. 992 (4), J = -5. 32 (5) cm-’, J’= 4. 2 (3) cm-’ for I and g = 1. 97 (l), J = -7. 38 (7) cm-’, J’= 12. 23 (3) cm-’ for 11. The observed Gd-Cu coupling ferromagnetic and fairly substantial, a result which opens new perspectives in the field of magnetic interactions between-earth and transition-metal ions.
Bencini et al. (Sun,) studied this question.