ja066744f_si_001.cif (25.75 kB)

Magnetic Ordering (Tc = 90 K) Observed for Layered [FeII(TCNE•-)(NCMe)2]+[FeIIICl4]- (TCNE = Tetracyanoethylene)

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posted on 13.12.2006 by Konstantin I. Pokhodnya, Michael Bonner, Jae-Hyuk Her, Peter W. Stephens, Joel S. Miller
[Fe(TCNE)(NCMe)2][FeCl4] is isolated from the reaction of TCNE and FeCl2(NCMe)2 and orders as a ferrimagnet below 90 K and is the initial member of a new class of magnets. It is the first metal−TCNE magnet with direct bonding between metal ion and [TCNE]•- whose structure has been determined, and it possesses a novel planar μ4-[TCNE]•- spin coupling unit bonded to four FeII's, with an axial pair of MeCNs. The [FeIIICl4]- anion occupies sites between the [FeII(TCNE•-)(NCMe)2]+ layers. [Fe(TCNE)(NCMe)2][FeCl4] has a coercive field of 1730 Oe and a remnant magnetization of 7500 emuK/mol at 50 K.