Magnetic Ordering (<i>T</i>_c = 90 K) Observed for Layered [Fe^II(TCNE^•-)(NCMe)₂]⁺[Fe^IIICl₄]^- (TCNE = Tetracyanoethylene)

[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.