STUDIES ON THE REACTIONS OF (ETA-5-CYCLOPENTADIENYL)DICARBONYLCOBALT WITH PHENYL-1-NAPHTHYLACETYLENE AND WITH PHENYL-2-NAPHTHYLACETYLENE, AND AN X-RAY CRYSTALLOGRAPHIC DETERMINATION OF ONE OF THE PRODUCTS - (ETA-5-CYCLOPENTADIENYL)-[ETA-4-1,3-DI-(1-NAPHTHYL)-2,4-DIPHENYLCYCLOBUTADIENE]COBALTP

The reactions of (η5-C5H5)Co(CO)2 with both phenyl-1-naphthylacetylene and phenyl-2-naphthylacetylene have been shown to produce all four possible η5-cyclobutadiene-cobalt complexes and all six possible η4-cyclopentadienone-cobalt derivatives. The structures of the η4-cyclobutadiene-cobalt complexes have been assigned on the basis of proton NMR and mass spectral studies, and unequivocally established by means of an X-ray diffraction investigation for one of the isomers as (η5-cyclopentadienyl)[η4-1,3-di(1-naphthyl)-2,4-diphenylcyclobutadiene]cobalt. This compound is triclinic, a = 10.88(2), b = 15.710(6), c = 8.728(4) Å, α = 95.09(4)°, β = 101.94(2)°, γ = 86.93(3)°. The space group is P1 with Z = 2. The structure was solved by Patterson and Fourier methods and refined by full-matrix least squares methods (4128 reflections above 3σ) to a final R = 0.036. Bond distances and angles are normal but the cyclobutadiene ring is not quite planar. One of the atoms is 0.047 Å out of the plane of the other three apparently to relieve steric stress. The two phenyl rings are almost coplanar with the cyclobutadiene ring (torsion angles 3.9 and 20.4°) while the naphthyl rings are almost perpendicular to it (torsion angles 63.8, 64°). © 1979.