Magnetic ordering (Tc = 90 K) observed for layered [Fe(II)(TCNE*-)(NCMe)2]+[Fe(III)Cl4]- (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 mu4-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.