The crystal structure of bis(phenylthio)acetylene, C14H10S2, was studied by
X-ray diffraction at 87 K. The space group is P2(1)/c, a = 14.6790(8) Angs
trom, b = 5.6481(3) Angstrom, c = 14.7115(11) Angstrom, beta = 105.60(1)deg
rees from repeated centrings on resolved MoKalpha 1 peaks, Z = 4. Intensity
data were collected with MoK<(alpha)over bar> radiation on three different
crystals, LO data with (sin theta)/lambda < 0.714 Angstrom(-1) on one crys
tal, and HO data in the (sin theta)/lambda range 0.682-0.857 Angstrom(-1) o
n two different crystals. The standard corrections were applied to the data
, including corrections for absorption, before merging. Structure solution
was by direct methods, refinement based on the full data set, 5757 F-o conv
erged at R-w = 0.036, a separate refinement including only non-hydrogen ato
ms and based on 3206 F-o with (sin theta)/lambda > 0.65 Angstrom(-1) gave a
final R-w = 0.031. The atomic sequence -S-C = C-S- is distinctly nonlinear
, the S-C (acetylene) bonds, average 1.6647(9)Angstrom, have significant do
uble bond character, and the central CEC bond, 1.2224(12) Angstrom, is abou
t 0.04 Angstrom longer than expected for a vicinally substituted carbon-car
bon triple bond. The pattern of angular deviations from 120 degrees in the
phenyl rings shows that the S atoms are electronegative substituents combin
ing sigma-electron withdrawal with some pi-electron donation. Both phenyl g
roups are nearly eclipsed with the acetylenic moiety which gives rise to tw
o short intramolecular H(phenyl)...C(acetylene) contacts, 2.49 Angstrom and
2.59 Angstrom.