Refinements of the crystal structures of 1,4-diphenylbutadiyne and its complex with two moles of Co-2(CO)(6)

1,4-diphenylbutadiyne C16H10, crystallizes in monoclinic space group P2(1)/n with a = 6.6152(6), b = 6.0768(7), c = 14.634(1) Angstrom beta = 100.981(8)degrees, V = 577.5(2) Angstrom(3), Z = 2. The structure was refined to R = 0.077 and R(w) = 0.069 for 1007 observed reflections with CuK alpha radiation. The molecule lies on an inversion center. Our determination represents and increase in precision of a factor of approximately three over the original determination. The 2:1 cobalt complex, C16H10[CO2(CO)(6)](2), also crystallizes in monoclinic space group P2(1)/n with a = 8.9568(12), b = 17.7057(10), c = 18.5671(12) Angstrom, beta = 90.606(12)degrees, V = 2944.3(5) Angstrom(3), Z = 4. The structure was refined to R = 0.032 and R(w) = 0.031 for 4312 observed reflections. The diphenylbutadiyne triple bonds elongate to 1.346(3) Angstrom and the angles at the diyne C atoms decrease to 134.1(3)-144.9(3)degrees upon complexation. The Co-Co distance is 2.4580(4) Angstrom. Our data represent an increase in precision by a factor of 2-3 over the original determination.