Molecular and crystal structure of hexa(phenylthio)-1,3-butadiene at 87 K

The crystal structure of hexa(phenylthio)-1,3- butadiene, C40H30S6, was Stu died by X-ray diffraction at 87 K. The space group is monoclinic, Ia, a = 1 3.947(2) Angstrom, b = 22.254(4) Angstrom, c = 11.610(2) Angstrom, beta = 1 06.54(1)degrees and Z = 4. Intensity data were collected with MoKalpha radi ation to (sin theta)/lambda < 0.705 Angstrom(-1). The structure was solved by direct methods. Refinement based on 4920 \F-o\ converged at R-w = 0.032. The central bond of the butadienyl core, 1.472(4) Angstrom, is comparable t o the single bond of unconjugated 1,3-butadiene, whereas the two double bon ds, 1.353(5) Angstrom and 1.371(5) Angstrom, are longer than expected for a C(sp(2)) = C(sp(2)) bond. This may be attributed in part to hybridization changes caused by the S atoms. The large torsion angle over the central bon d C1-C2-C3-C4 = -66.8(4)degrees, reflects the accommodation of this fragmen t to a highly crowded intramolecular environment. All phenyl rings have int ramolecular contacts within van der Waals radii with at least one other rin g and one of the butadiene carbon atoms. The sulfur atoms are engaged in an inner loop of short 1, n S ... S contacts in the range 3.070(3) Angstrom - 3.429(4) Angstrom for n greater than or equal to 3. Averaged deviations fro m 120 degrees in the ipso, 0.5(1)degrees, and ortho, -0.5(1)degrees, positi ons of the six phenyl rings show that the S atoms serve as electronegative substituents attracting electron density from the rings.