Electrochemically Generated Peryleniumyl-Hexafluorophosphate and Hexafluoroarsenate: New One-Dimensional Metals

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Abstract
Compounds of stoichiometry (pe)2(PF6)1.1 × 0.8CH2Cl2(1) (pe = perylene), (pe)2(AsF6)1.1 × 0.7 CH2Cl2 (2), (pe)2(PF6)1.4 × 0.6 THF (3), (pe)2(AsF6)1.5 × 0.5 THF (4) and (pe)3(SbF6)2 × 0.75 CH2Cl2 (5) have been obtained as crystalline samples by electrochemical deposition from CH2Cl2 [(1), (2) and (5)] or from THF [(3) and (4)] solutions of perylene, containing the appropriate counterion. The three compounds (1)-(3) crystallize in isomorphous orthorhombic lattices. (1) forms black needles: space group Pnmn with a = 4.285 Å, b = 12.915 Å and c = 14.033 Å, z = 1. (2) gives black needles, orthorhombic space group Pnmn with a = 4.294 Å, b = 13.077 Å, and c = 14.132 Å, z = 1. The structures of (1) and (2) were solved by direct methods and refined by least squares to final R = 0.148 and R = 0.088 based on 476 and 322 observed reflections. The perylene forms segregated stacks in direction of the a-axis with interplanar distances of 3.40 Å and an angle of 37.7° between the bc-plane and the perylene. The channels between the segregated stacks are filled by anions and solvent molecules. The d.c. conductivities (four probe measurements) of (1)-(4) fall in the range of 70–1200Ω−1. cm−1 at room temperature. The conductivities show a metallic regime down to about 200°K and drop off below that temperature.