Amber C. McConnell

MnII(TCNE)3/2(I3)1/2-A 3D network-structured organic-based magnet and comparison to a 2D analog

Mn{sup II}(TCNE){sub 3/2}(I{sub 3}){sub 1/2} and Mn{sup II}(TCNE)[C{sub 4}(CN){sub 8}]{sub 1/2} [tetracyanoethylene (TCNE)] are organic-based magnets with 3D and 2D extended network structures with vastly different magnetic behavior. They have similar ferrimagnetic coupled layers of Mn{sup II}(TCNE){sup {lg_bullet}-} with different interlayer couplings, which lead, respectively, to net ferrimagnetic (T{sub c} = 171 K) and antiferromagnetic (T{sub c} = 68 K) order.

Structure and magnetic ordering of a 2-D MnII(TCNE)I(OH2) (TCNE = tetracyanoethylene) organic-based magnet (Tc = 171 K)

Mn(II)(TCNE)I(OH(2)) was isolated from the reaction of tetracyanoethylene (TCNE) and MnI(2)(THF)(3), and has a 2-D structure possessing an unusual, asymmetric bonded μ(4)-[TCNE]˙(-). Direct antiferromagnetic coupling between the S = 5/2 Mn(II) and S = 1/2 [TCNE]˙(-) leads to magnetic ordering as a canted antiferrimagnet at a T(c) of 171 K.

Pressure-Induced Transition from an Antiferromagnet to a Ferrimagnet for MnII(TCNE)[C4(CN)8]1/2 (TCNE = Tetracyanoethylene)

Mn(II)(TCNE)[C(4)(CN)(8)](1/2) (TCNE = tetracyanoethylene) exhibits a reversible pressure-induced piezomagnetic transition from a low magnetization antiferromagnetic state to a high magnetization ferrimagnetic state above 0.50 ± 0.15 kbar. In the ferrimagnetic state, the critical temperature, T(c), increases with increasing hydrostatic pressure and is ~97 K at 12.6 kbar, the magnetization increases by 3 orders of magnitude (1000-fold), and the material becomes a hard magnet with a significant remnant magnetization.