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Studies of {[1](1,1′)Ferroceno[1](1,1′)ruthenocenophane}-1-ylium Hexafluorophosphate and Related α -Carbonium Salts

1996; Oxford University Press; Volume: 69; Issue: 10 Linguagem: Inglês

10.1246/bcsj.69.2877

1348-0634

Masanobu Watanabe, Izumi Motoyama, Toshio Takayama,

Magnetism in coordination complexes

Abstract The oxidation of [1](1,1′)ferroceno[1](1,1′)ruthenocenophane ([1.1]FcRc) and ferrocenylruthenocenylmethane (FcCH2Rc) with bromo- or chlorobis(η5-cyclopentadienyl)ruthenocenium(1+) hexafluorophosphates gave the title compound, [Fe(C5H4CH2C5H4)(C5H4CH+C5H4)Ru]PF6− (1), as an α-carbonium salt and ferrocenylruthenocenylmethylium+ hexafluorophosphate [FeCp(C5H4CH+C5H4)CpRu]PF6− (3), respectively. The crystal of 1 has been found to be triclinic, space group , a = 10.572(9), b = 10.581(3), c = 9.680(5) Å, α = 99.50(3)°, β = 108.14(5)°, γ = 88.30(5)°, Z = 2, and the final R = 0.082 and Rw = 0.094. The distance between the Ru and Fe is 4.507(3) Å; which is much shorter than the value of neutral [1.1]FcRc one (4.792(2) Å). The two C5H4-rings in the Rc moiety are tilted largely (the tilting angle is 10.74°) due to a strong Ru···Cα (α-metylium) interaction. The crystal of 3 has been found to be orthorhombic, space group Pbca, a = 17.062(5), b = 19.172(6), c = 12.580(7) Å, Z = 8, and the final R = 0.067 and Rw = 0.072. The tilting angle of the Rc moiety is 7.98°. The most interesting difference between 1 and 3 is found in the distance between the Ru and Cα atoms; i.e., the distance of 3 (2.43(2) Å, closer to the Ru–C covalent bond) is significantly shorter than the value of 1 (2.51(1) Å, somewhat longer to the covalent bond); therefore, the greater positive –CH+– charge can be stabilized by a delocalization of the charge over the [RuCp(C5H4CH)]+ fragment for 3. However, the –CH+– charge is spread out over [Fe(C5H4CHC5H4)(C5H4CH2C5H4)Ru]+ for 1. Temperature-dependent 57Fe-Mössbauer spectroscopy (areal intensity ratio of ferrocene and ferrocenium) supports above the conclusion.