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Closed Access item Synthesis, structural analysis, and magnetic properties of ethylmalonate-manganese(II) complexes

Authors:Déniz, Mariadel
Pasán, Jorge
Ferrando-Soria, J.
Fabelo, Oscar
Cañadillas-Delgado, Laura
Ruiz-Pérez, Catalina
Issue Date:2011
Publisher:American Chemical Society
Citation:Inorganic Chemistry 50(21): 10765-10776 (2011)
Abstract:Five manganese(II) complexes of formulas [Mn2(Etmal)2(H2O)2(L)]n (1–4) and {[Mn(Etmal)2(H2O)][Mn(H2O)4]}n (5) with H2Etmal = ethylmalonic acid (1–5) and L = 1,2-bis(4-pyridyl)ethane (bpa) (1), 4,4′-azobispyridine (azpy) (2), 4,4′-bipyridyl (4,4′-bpy) (3), and 1,2-bis(4-pyridyl)ethylene (bpe) (4) were synthesized and structurally characterized by single crystal X-ray diffraction. Their thermal behavior and variable-temperature magnetic properties were also investigated. The structure of the compounds 1–4 consists of corrugated layers of aquamanganese(II) units with intralayer carboxylate-ethylmalonate bridges in the anti-syn (equatorial-equatorial) coordination mode which are linked through bis-monodentate bpa (1), azpy (2), 4,4′-bpy (3), and bpe (4) ligands to build up a three-dimensional (3D) framework. The structure of compound 5 is made up by zigzag chains of manganese(II) ions with a regular alternation of [Mn(H2O)4]2+ and chiral (either Δ or λ enantiomeric forms) [Mn(Etmal)2(H2O)]2– units within each chain. In contrast to the bidentate/bis-monodentate coordination mode of the Etmal ligand in 1–4, it adopts the bidentate/monodentate coordination mode in 5 with the bridging carboxylate-ethylmalonate also exhibiting the anti-syn conformation but connecting one equatorial and an axial position from adjacent metal centers. The manganese–manganese separation through the carboxylate-ethylmalonate bridge in 1–5 vary in the range 5.3167(4)–5.5336(7) Å. These values are much shorter than those across the extended bis-monodentate N-donors in 1–4 with longest/shortest values of 11.682(3) (3)/13.9745(9) Å (4). Compounds 1–5 exhibit an overall antiferromagnetic behavior, where the exchange pathway is provided by the carboxylate-ethylmalonate bridge. Monte Carlo simulations based on the classical spin approach (1–5) were used to successfully reproduce the magnetic data of 1–5.
Description:12 páginas, 10 figuras, 6 tablas.-- et al.
Publisher version (URL):http://dx.doi.org/10.1021/ic201314k
E-ISSNmetadata.dc.identifier.doi = DOI:1520-510X
Appears in Collections:(ICMA) Artículos

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