2 COBALTACYCLOPENTADIENE COMPLEXES AND ONE CYCLOBUTADIENE COMPLEX

The structures of three cobalt complexes, [1,4-bis(1-propynyl)-2,3-dimethyl-1 ,3-butadiene-1,4-diyl](eta 5-cyclopentadienyl)(triphenylphosphine)cobalt, [Co(C5H5)(C12H12)(C18H15P)], (eta(5)-cyclopentadienyl)[2,4-diphenyl-1,3 -bis(phenylethynyl)-1,3-butadiene-1,4-diyl](triphenylphosphine)cobalt, [Co(C5H5)(C32H20)(C18H15P)], and (eta(4)-1,3-bis(trimethylsilyl)-2,4-bis[4'-(trimethylethyl) biphenyl-4-yl] cyclobutadiene}(eta(5)-cyclopentadienyl)cobalt, [Co(C5H5)(C44H52Si4)], have been determined by single-crystal X-ray diffraction.