Structural Investigation of a B-ferrocenyl-substituted Tetracarbon Carborane, 4-[(η⁵-C₅H₅)Fe(η⁵-C₅H₄)]-2,3,7,8-(CH3)₄C₄B₈H₇


The title compound was isolated as a product of the reaction of (CH3)4C4B8H8 with sodium naphthalenide, FeCl2, and NaC5H5 in tetrahydrofuran and was structurally characterized from its 11B and 1H NMR spectra, its mass spectra, and a single-crystal X-ray diffraction study. The molecule consists of a C4B8 distorted-icosahedral cage which essentially corresponds to that of the previously reported (CH3)4C4B8H8 species, with a ferrocenyl group attached to B(4). The present structure represents a significant improvement in precision over that of the earlier unsubstituted carborane. There are no marked structural effects in the polyhedron that can be attributed to the ferrocenyl group, but the C5H4 ring attached to boron is itself significantly perturbed; electron delocalization between the C5H4 ring and the carborane is suggested as a possible cause. The molecule crystallizes in the monoclinic space group P21/n with a = 11.044 (2) Å, b = 7.999 (1) Å, c = 23.697 (11) Å, β = 94.58 (3)°, V = 2087 Å3, and ρ(calcd) = 1.23 g cm-3 for Z = 4. Full-matrix least-squares refinement of the positional and anisotropic thermal parameters for all nonhydrogen atoms, with varying isotropic thermal parameters for hydrogen atoms included for several cycles and thereafter held invariant, converged at R = 0.054 for the 2217 independent reflections for which Fo 2 > 3σ(Fo 2). © 1980 American Chemical Society.



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© 1980 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Jan 1980