Synthesis and X-ray structure of a semiconducting organometallic salt [FeCp(Tol)]2[Ni(mnt)2]

The compound [FeCp(Tol)]2[Ni(mnt)2] has been prepared from [FeCp(Tol)]AlCl4 and Na2 [Ni(mnt)2]. This new organometallic radical ionic salt has been characterized by elemental analysis, IR, 1H NMR and mass spectroscopy. The X-ray structure of the compound shows there are segregated cation and anion stacks in the perpendicular directions. The molecular anions form a zig-zag stacking along the b axis, and between every two neighbouring anion planes a methyl group of the cation is inserted. This gives rise to a long spacing of 6.87 Å between the anion planes. The cations stack along the c axis, with the closest spacing of 3.457 Å between the cyclopentadienyl plane and the neighbouring toluene plane, which is shorter than the sum of Van der Wall′s radii. Conductivity measurements showed the compound as a semiconductor with a room temperature conductivity of 1.6 × 10−4Scm−1.