Crystal structure, magnetic and spectroscopic properties of the bis(dimethyl sulfoxide) adduct of tetra-μ-formato-dicopper(II), a new tetracarboxylato-bridged copper(II) dimer
1994; Elsevier BV; Volume: 216; Issue: 1-2 Linguagem: Inglês
10.1016/0020-1693(93)03728-s
ISSN1873-3255
AutoresFernando Sapiña, Marcelino Burgos, Emilio Escrivá, José-Vicente Folgado, Daniel Beltrán, Pedro Gómez‐Romero,
Tópico(s)Metal-Catalyzed Oxygenation Mechanisms
ResumoThe crystal and molecular structure of a new tetracarboxylato-bridged copper(II) dimer, the bis(dimethyl sulfoxide)tetrakis(μ-formato)dicopper(II) has been determined by X-ray diffraction methods. It crystatlizes in the tetragonal space group I41/a, with Z=8 in a cell of dimensions a=17.688(2), c=10.408(1) Å. The structure is built up of centrosymmetric neutral dimers [Cu2(HCOO)4(dmso)2], where four bidentate carboxylate anions form syn-syn bridges between the metal atoms which are in a 4 + 1 environment. Magnetic susceptibility data show that the copper atoms are strongly antiferromagnetically coupled with J=−434 cm−1. The obtained triplet-singlet energy gap is compared with those reported for a series of related dimers. Finally, the ESR spectrum shows characteristic features of a triplet state with a non-negligible zero field splitting, being typical of the copper(II) dimeric tetracarboxylates.
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