کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1308505 | 975174 | 2009 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Antiferromagnetic interactions through phenoxo bridges and lattice water: Synthesis, structure, and magnetic properties of new Mn(III) Schiff base complexes in combination with thiocyanate ligand Antiferromagnetic interactions through phenoxo bridges and lattice water: Synthesis, structure, and magnetic properties of new Mn(III) Schiff base complexes in combination with thiocyanate ligand](/preview/png/1308505.png)
The Schiff base ligands, N,N′-bis(2-hydroxyacetophenone)-1,2-diaminoethane (acphenH2) and N,N′-bis(2-hydroxyacetophenone)-1,3-diaminopropane (acphpnH2), prepared in situ were used to synthesise two new Mn(III) complexes which were characterised by crystallography and variable temperature magnetic measurements. [Mn(acphen)NCS]2 is a phenoxo-bridged dimeric compound with the thiocyanate coordinating in the usual bent mode (Mn–N–C angle, 152°) and is weakly antiferromagnetic. Since there are no significant inter-dimer contacts in the crystal, the low temperature magnetic behaviour is influenced by single ion zero-field splitting. Exact diagonalisation of the spin Hamiltonian was performed to derive the following parameters: J = −0.7 cm−1, D = −0.6 cm−1. Mn(acphpn)(H2O)NCS is monomeric with an unusual linearly coordinated thiocyanate (Mn–N–C angle, 178°). Two lattice water molecules link the Mn(III) complex molecules through hydrogen bonds to form one-dimensional chains in the crystal. Magnetic exchange along the chain makes this compound also weakly antiferromagnetic with J ∼ –2 cm−1.
A 7-atom long bridge involving two lattice water molecules causes antiferromagnetic coupling in the crystals of a mononuclear Mn(III) Schiff base complex which is comparable in magnitude to that observed in phenoxo-bridged dinuclear complexes.Figure optionsDownload as PowerPoint slide
Journal: Inorganica Chimica Acta - Volume 362, Issue 9, 1 July 2009, Pages 3247–3252