Molecular structure of some [1.1 ]ferrocenylruthenocenophanium (n = 1,2 polyiodides salts

Oxidation of 1.1]ferrocenylruthenocenophane with a large excess and 1.5 equivalents of iodine gives dicationic iodo1.1]ferrocenylruthenocenophanium²⁺I₃⁻ · 0.5I₂2 (1) and monocationic 1.1]ferrocenylruthenocenophanium⁺I₃⁻ (2) salts respectively. The structures of 1 and 2 were analyzed by single-crystal X-ray diffraction studies. The crystal form of 1 is monoclinic space group C2/c, A = 21.35](5), B = 20.594(5), C = 17.397(4) Å, β = 124.17(1)°, Z = 8, and the final R = 0.068 and R_w = 0.070. The cation formulated as Fe^III(C₅H₄CH₂C₅H₄)₂Ru^IVI]²⁺ exists in a syn-conformation as in the cases of the neutral compound. The distance between the Ru^IV and Fe^II is 4.656(4) Å, which is much shorter than the value of the neutral compound (4.792(2) Å), and the bond angle of I---Ru^IV,Fe^III is 81.26°. The dihedral angle between the two η⁵-C₅H₄ (fulvenide) rings on the Ru^IV moiety is 37.56° due to the Ru^IV---I bond (2.758(3) Å). These two rings of Fe^III and Ru^IV moieties are essentially eclipsed. The unit cell has three kinds of I₃⁻ (I_3a⁻, I_3b⁻ and I_3c⁻) and one I₂, and the formula of 1 is given as Fe^III(C₅H₄CH₂CSH₄)₂Ru^IVI]²⁺I₃⁻ · 0.5(I₃⁻)₂ · 0.5I₂. The crystal of 2 formulated as Fe^III(C₅H₄CH₂C₅H₄)₂Ru^II]⁺I₃⁻ is triclinic space group

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, and the final R = 0.067 and R_w = 0.068. The unit cell has two independent molecules (unit A and B); i.e. two kinds of distance between the Ru^II and Fe^III, are observed; one (A) is 4.615(3) and the other (B) is 4.647(3) α. The two η⁵-C₅H₄ rings of both Fe^III and Ru^II are essentially staggered and the dihedral angles between the rings of FcH and RcH moieties are less than 5.8°. Typical ferrocenium-type broad singlet ⁵⁷Fe-Mössbauer lines are observed for both salts (1, 2) at all temperatures.