STUDIES ON THE INTERACTIONS OF (η5-C5H5)M(CO)2 COMPLEXES (M=Co, Rh) WITH 1,2-BIS(PHENYLETHYNYL)BENZENE, AND AN X-RAY CRYSTALLOGRAPHIC CHARACTERIZATION OF ONE OF THE PRODUCTS: (η5-C5H5Co)2(C6H5C2C6H4C2C6H5)2

Article abstract of DOI:10.1016/S0022-328X(00)81922-1

The reaction of (η⁵-C5H5)Co(CO)2 (1) and 1,2-bis(phenylethynyl)benzene (4) has been shown to produce as major products a dimeric organic compound of composition C44H28, postulated to be 1,2,4-triphenyl-3-(o-phenylethynylphenyl)biphenylene (7), and bis(η⁵-C5H5Co)2(C6H5C2C6H4C2C6H5)2 (9).Minor organometallic products also obtained include a bis(η⁴-cyclopentadienone)dicobalt complex (12) and several mononuclear complexes resulting from co-condensation of 4 and 7 with 1.A corresponding reaction between (η⁵-C5H5)Rh(CO)2 (2) and 4 has produced several organorhodium complexes in low yield, including a mixed (η⁴-cyclobutadiene)(η⁴-cyclopentadienone)dirhodium derivative (17).Complexes 9, 12 and 17 are derived from the intermolecular condensation of two molecules of 4 with either 1 or 2.An X-ray diffraction investigation of 9 has been undertaken, and unequivocally confirms the unique structural nature of this complex to be that of the b isomer. 9b crystallizes in the monoclinic space group P2₁/n with cell dimensions: a=10.652(5), b=23.690(6), c=17.204(4) Angstroem, and β=90.21(3) deg; V=4341(4) Angstroem³.The unit cell was found to contain one solvent benzene for each molecule, yielding a calculated density of 1.351(1) g/cm³ with Z=4.Intensity data were collected using Mo-K_α radiation (λ=0.71073 Angstroem) by the θ-2θ scan method with an automated 4-circle diffractometer (Enraf-Nonius CAD-4).In all, 8286 reflections were scanned, of which 5192 were independent with an intensity greater than 3?.Refinement by full matrix least squares led to a final unweighted R of 0.037 (R_w=0.050).The atoms of the (η⁵-C5H5)Co(C4) moieties are well-behaved crystallographically and have molecular parameters which are within accepted values of recent determinations of other complexes containing that moiety.