Organotransition-metal Metallacarboranes 7
Complexes of polycyclic arenes: Preparation and structures of (η⁶-arene)ferracarborane sandwiches of naphthalene and phenanthrene
The reaction of a (cyclooctatriene)ferracarborane complex, (η6-C8H10)Fe(Et2C 2B4H4) (1), with naphthalene at 200°C or with phenanthrene at 175°C, both in the absence of solvent, gave respectively red (η6-naphthalene)Fe(Et2C2B4H 4) (3) and (η6-phenanthrene)Fe(Et2C2B 4H4), the latter as red (4) and yellow (5) isomers. Compounds 3-5 were obtained as air-stable crystals. The reaction of 1 with naphthalene over Al/AlCl3 followed by treatment with CH3OH gave a mixture of (arene)Fe(Et2C2B4H4) products in which the arene ligands are proposed to be dihydronaphthalene and tetrahydronaphthalene, respectively. The structures of 3, 4, and 5 were determined via high-resolution 11B and 1H NMR, IR, and mass spectra and X-ray diffraction studies on 3 and 4. In 3 the iron atom is η6-coordinated in nearly symmetrical fashion to one ring of naphthalene, the Fe-C(9) and Fe-C(10) distances being slightly longer than the other Fe-C bonds; the naphthalene ligand is essentially planar and is almost parallel to the carborane bonding face (dihedral angle 3.54°). In 4, the metal is η6-coordinated to an end ring of phenanthrene and is nearly centered over that ring; the phenanthrene is tilted slightly (5.30°) with respect to the carborane ring plane. The phenanthrene ligand is not quite planar, the three ring planes exhibiting small dihedral angles (≤4°) with respect to each other. The structures of 3 and 4 are comparable to those of (η6-arene)Cr(CO)3 (arene = naphthalene and phenanthrene); however, the metal-arene distance (∼1.50 Å) in 3 and 4 is much shorter than in the chromium complexes. Crystal data for 3: Mr = 309, space group P21/c, Z = 4, a = 8.588 (3) Å, b = 14.798 (5) Å, c = 13.397 (5) Å, β = 103.52 (2)°, V = 1655 Å3, R = 0.058 for 1876 reflections having Fo 2 > 3σ(Fo 2). Crystal data for 4: Mr = 364, space group P21/c, Z = 4, a = 11.817 (3) Å, b = 10.231 (4) Å, c = 16.362 (4) Å, β = 108.56 (2)°, V = 1875 Å3, R = 0.078 for 1550 reflections having Fo 2 > 3σ(Fo 2). © 1985 American Chemical Society.
R. G. Swisher et al., "Organotransition-metal Metallacarboranes 7," Organometallics, American Chemical Society (ACS), Jan 1985.
The definitive version is available at http://dx.doi.org/10.1021/om00124a017
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© 1985 American Chemical Society (ACS), All rights reserved.