?-POLYOLEFIN AND ?-ACETYLENE COBALT(I) COMPLEXES WITH THE TRIS(TERTIARY PHOSPHINE) 1,1,1-TRIS(DIPHENYLPHOSPHINOMETHYL)ETHANE. X-RAY STRUCTURE OF 4-C7H8)>ClO4*0.5 CH2Cl2

Article abstract of DOI:10.1016/S0022-328X(00)86082-9

Cationic cobalt(I) complexes with the general formula <(triphos)Co(L)>Y (triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane; L = 1,3-butadiene, isoprene, 1,3-cycohexadiene, 1,3,5-cycloheptatriene, 1,3,5,7-cyclooctatetraene, phenylacetylene, diphenylacetylene) have been obtained by reaction of cobalt perchlorate with a variety of conjugated polyolefins or with acetylenes in the presence of the triphos ligand.The crystal structure of the complex <(triphos)Co(C7H8)>ClO4*0.5 CH2Cl2 has been determined by an X-ray analysis using diffractometric data.The crystals are monoclinic, space group P2₁/c with cell dimensions a 10.514(3), b 15.041(5), c 54.795(12) Angstroem, β 92.61(3) deg, Z = 8.The structure was solved by direct methods and refined by least-squares techniques to a final conventional R factor of 0.091.The structure, which consists of <(triphos)Co(C7H8)>⁺ cations, perchlorate anions, and interposed CH2Cl2 solvent molecules, shows that the cycloheptatriene molecule acts as a tetra-hapto ligand.The coordination polyhedron can be regarded either as a distorted square pyramid or as a distorted octahedron.The coordination geometries of all complexes have been assigned on the basis of this structure determination and of IR and NMR data.