Unusual (-aqua)bis(-carboxylate) Bridge in Homometallic M(II) (M = M
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- 作者：Laura Cañ ; adillas-Delgado ; Oscar Fabelo ; Jorge Pasá ; n ; Fernando S. Delgado ; Francesc Lloret ; Miguel Julve ; Catalina Ruiz-Pé ; rez
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：September 3, 2007
- 年：2007
- 卷：46
- 期：18
- 页码：7458 - 7465
- 全文大小：261K
- 年卷期：v.46,no.18(September 3, 2007)
- ISSN：1520-510X
文摘
The first coordination compounds of 1,2,3,4-butanetetracarboxylate anion (butca<SUP>4-) of the formula [M2(butca)(H2O)5]n·2nH2O [M = Mn(II) (1), Co(II) (2), and Ni(II) (3)] were prepared and their X-ray crystal structures andmagnetic properties investigated. The three complexes have a very similar two-dimensional structure which consistsof (4,4) networks, 1 and 2 being isostructural. The tetracarboxylate ligand acts as a 4-fold connector leading totwo-dimensional (4,4) networks of metal atoms, this topology being possible because of its planar conformation.The nodes of these networks are formed by dinuclear motifs which exhibit the unusual (
-aqua)bis(-carboxylate)bridging unit which is analogous to that observed in some molecules of biological interest. The variable-temperaturemagnetic susceptibility measurements of 1-3 show that 1 and 2 are antiferromagnetically coupled systems whereas3 exhibits a ferromagnetic behavior. The analysis of the magnetic data of 1-3 through a simple dinuclear modelallowed the determination of the values of the magnetic coupling (J) -3.6 (1), -1.2 (2), and +1.47 cm-1 (3) withthe Hamiltonian being defined as H = -JSA·SB. The countercomplementarity between the two bridges (aqua andsyn-syn carboxylate) accounts for the trend exhibited by the values of the magnetic coupling in this family.
-aqua)bis(-carboxylate)bridging unit which is analogous to that observed in some molecules of biological interest. The variable-temperaturemagnetic susceptibility measurements of 1-3 show that 1 and 2 are antiferromagnetically coupled systems whereas3 exhibits a ferromagnetic behavior. The analysis of the magnetic data of 1-3 through a simple dinuclear modelallowed the determination of the values of the magnetic coupling (J) -3.6 (1), -1.2 (2), and +1.47 cm-1 (3) withthe Hamiltonian being defined as H = -JSA·SB. The countercomplementarity between the two bridges (aqua andsyn-syn carboxylate) accounts for the trend exhibited by the values of the magnetic coupling in this family.