Bimetallic cyanido-bridged magnetic materials derived from manganese(III) Schiff-base complexes and pentacyanidonitrosylferrate(II) precursor

Rodica Ababei (1, 2, 3) , Yang-Guang Li (1, 2) , Olivier Roubeau (1, 2) , Marguerite Kalisz (1, 2) , Nicolas Bréfuel (1, 2) , Claude Coulon (1, 2) , Etienne Harté (1) , Xueting Liu (1) , Corine Mathonière (3) , Rodolphe Clérac (1, 2)

1 CRPP - Centre de recherches Paul Pascal
2 UB - Université Sciences et Technologies - Bordeaux 1
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Three heterobimetallic MnIIIFeII complexes: [Mn(5-Br-salpn)(H2O)]2[Fe(CN)5NO]2H2O (1), [{Mn(salen)}2Fe(CN)5NO]2H2O (2) and [{Mn(saltmen)}4Fe(CN)5NO](ClO4)2H2O2CH3OH (3), have been synthesized by the reactions of MnIII/Schiff–base (SB) complexes, [Mn(SB)(H2O)]+, (SB being salen2 =N,N0-ethylenebis(salicylideneiminato) dianion; 5-Br-salpn2 = N,N0-1,3-propylenebis(5-bromosalicylideneiminato) dianion or saltmen2 = N,N0-(1,1,2,2-tetramethylethylene) bis(salicylideneiminato) dianion) with the [Fe(CN)5NO]2building block. X-Ray diffraction analyses on single crystals reveal that 1 has a trinuclear molecular structure, 2 displays a two-dimensional (2D) network structure, and 3 possesses a new 2D network of MnIII dinuclear motifs. The magnetic measurements show that the interaction between the MnIII S = 2 spins through the [NRC–Fe–CRN] bridges is systematically of antiferromagnetic nature: J/kB = 0.95(5) K and J/kB = 1.15(5) K for 1 and 2, respectively, while the direct MnIII–MnIII interaction, in the {Mn2(saltmen)2} dinuclear units present in 3, is ferromagnetic with J/kB = +1.75(5) K. Due to the ST = 4 spin ground state of these dinuclear units and the uniaxial magnetic anisotropy brought by the Mn(III) metal ions, 3 exhibits singlemolecule magnet properties. The 400–900 nm optical properties of the three compounds have been also investigated, showing no significant photoactivity unlike in the Na2[Fe(CN)5NO precursor

Domaines: Chimie de coordination; Matériaux

Rodica Ababei, Yang-Guang Li, Olivier Roubeau, Marguerite Kalisz, Nicolas Bréfuel, et al.. Bimetallic cyanido-bridged magnetic materials derived from manganese(III) Schiff-base complexes and pentacyanidonitrosylferrate(II) precursor. New Journal of Chemistry, 2009, 33, pp. 1237-1248. ⟨10.1039/b903399h⟩. ⟨hal-00395422⟩