L.D.Patsenker, V.N.Baumer, V.P.Kuznetsov
Received May 12, 1998
Molecular and crystalline structures of 2-(pyrid-2-yl)-5-(thien-2-yl)-
1,3,4-oxadiazole (I) and 2-phenyl-5-(fur-2-yl)-1,3,4-oxadiazole
(II) have been studied using X-ray structure analysis. Both
molecules are essentially planar, the angles between planes of neighboring
cycles do not exceed 4 deg. in I and 12 deg. in II. Molecular
conformations are characterized by that double bonds C=C of furane
and thiophene rings, respectively, are in s-trans- conformation
with respect to C=N bonds of the oxadiazole cycle. The increased
length of the bond between oxadiazole and thiophene cycles in 2,5-di-(thien-2-yl)-1,3,4-oxadiazole
(studied before) as compared to that in the compound I has been
shown to be due to peculiarities in the crystal packing and to specific
molecular interactions in the crystal.