|dc.description.abstract||The cr ystal structure of the compound 2-benzoylethylidene-3-(2,4-
(BRMEO) has been determined by using three dimensiona l x-ray diffraction
data. The crys tal form is monoclinic, space group P21/c, a = 17.492(4),
o -.t' 0 R 0 b =: 16.979(1), c = 14.962(1) A, "X. =o= 90 ',= 106.46(1) , z = 8,
graphite-monochromatized Mo~ rad iation, Jl= 0.710J3~, D = 1.62g/cc and o
D = 1.65g/cc. The data were col lected on ~ Nonius CAD-4 c
diffractometer. The following atoms were made anisotropic: Br, S, N, 0,
C7, and C14-C16 for each i ndependent molecu le ; the rest were left
isotropic. For 3112 independent refl ec tions with F > 6G\F), R == 0.057.
The compound has two independent molecules within the asymmetric
unit. Two different conformers were observed which pack well together.
/l The S---O interaction distances of 2.493(6) and 2 . 478(7) A were observed
for molecules A and B respectively. These values are consistent with
earlier findings for 2-benzoylmethylene-3-(2,4-dibromophenyl)-
2,3-dihydro-5-phenyl-l,3,4-thiadiazole C22H14Br2N20S (BRPHO)
5-phenyl-l,3,4-thiadiazole C24H18Br2N20S (BRPETO ) where S---O distances are
l ess than the van der Waals (3.251\) but greater than those expected for
() a single bond (1.50A). From the results and the literature it appears
obvious that the energy/reaction coordinate pathway has a minimum
between the end structures (the mono- and bicyclic compounds).
* See reference (21) for nomenclature.||en_US