Synthesis, structure, and magnetic characterization of a hysteretic charge-transfer salt metamagnet, decamethylferrocenium 2,3-dicyano-1,4-naphthoquinonide, [Fe(Cp*)(2)][DCNQ]

The synthesis and single-crystal structure of a new one-to-one charge-trans fer salt, derived from decamethylferrocene and 2,3-dicyano-1,4-naphthoquino ne, are described. [Fe(Cp*)(2)][DCNQ] crystallizes in the orthorhombic spac e group Pbca, with a = 17.3149(5) Angstrom, b = 14.6862(4) Angstrom, c = 21 .0507(6) Angstrom, and Z = 8. Magnetization vs temperature data obtained in 100 G suggest that the compound exhibits dominant one-dimensional ferromag netic coupling and that it subsequently undergoes an antiferromagnetic phas e transition below T-N approximate to 4 K. Results of magnetization vs appl ied field experiments show that the compound is a metamagnet with a critica l field of approximately 3 kG at 1.8 K. In the nominally antiferromagnetic state, apparent canting of the moments gives rise to a small amount of hyst eresis. This picture is supported by ac susceptibility data. The Fe-57 Moss bauer spectrum exhibits the expected decamethylferrocenium unresolved quadr upole doublet (delta = 0.53 mm/s) at 77 K and magnetic hyperfine splitting, H-int = 37.9 T, corresponding to long-range magnetic order at 1.63 K.