Synthesis of fe–li–cr multinuclear complexes as molecular magnet materials

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ITB J. Sci. Vol. 40 A, No. 1, 2008, 62-70

Synthesis of Fe–Li–Cr Multinuclear Complexes as Molecular Magnet Materials
Djulia Onggo, Iis Siti Jahro, Fahimah Martak & Ismunandar Inorganic and Physical Chemistry Group, Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung, Jalan Ganesha 10 Bandung 40132, Indonesia Email: [e-mail]

Abstract. Multinuclear complexes have received considerable interest as molecular magnet materials. Up to now, several complex compounds based on bidentate ligand 2,2’ bipyridine have been synthesized. In this research, the FeLi-Cr multinuclear complexes with derivative 2’2- bipyridine ligands: 2-(2’pyridyl)quinoline(pq), 2,2’-Pyridil(pdl) have been synthesized. The oxalate (ox) ligand has also been used as a bridging ligand in these multinuclear complexes. and The chemical formula of Li[FeCr(ox)2(pq)(BF4)2(H2O)2] [Fe(pdl)n][LiCr(ox)3] complexes have been verified using metal and C, H, N elemental analysis data. The IR spectra in 350 – 4000 cm-1 range exhibit characteristic absorptions, which support the proposed structure of complex. The plausible structure of the compounds has been drawn based on complex formation mechanism. The magnetic susceptibility at room temperature of the pq-complex is about 5.7 BM and of the pdl- complexes are 4.8 and 5.5 BM. These indicated that both spin states of iron(II) exist in the multinuclear complexes. Keywords: 2-(2’-pyridyl)quinoline(pq); 2,2’-pyridil(pdl); Fe-Li-Cr multinuclear complexes; oxalate(ox) ligands.

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Introduction

Molecular magnet materials are chemical compounds which able to show magnetic properties on molecular scale. The magnetic behaviour of such compounds is based on a microstructure of active materials. For example, iron(II) complexes can be either paramagnetic or diamagnetic depending on their electronic spin state which is influenced by the ligand field strength [1], [2]. When strong field ligands such as 2,2’-bipyridine(bpy), are