Crystal structures of two substituted 2,5-diaryl-1,3,4-oxadiazoles

The crystal structures of 2.5-di(4-pyridyl)-1,3,3-oxadiazole, I, and 2-(4-c yanophenyl)-5-(4-dimethylaminophenyl)-1,3,4-oxadiazole, II, were determined from single crystal data (I: monoclinic, C-2/c(no. 15), a = 5.3119(9) Angs trom. b = 12.142(3) Angstrom, c = 16.771(3) Angstrom, beta = 93.41(2)degree s, R-all = 0.0774. II: triclinic, P (1) over bar (no. 2), a = 7.3908(12) An gstrom, b = 8.7992(15) Angstrom. c = 12.036(2) Angstrom, alpha = 77.04(2)de grees, beta = 89.29(2)degrees, gamma = 87.58(2)degrees, R-all = 0.0552). In both structures the formation of stacks of the almost planar molecules is observed as known for other oxadiazoles. These compounds exhibit difference s to other substituted 2,5-diaryl-1,3.4-oxadiazoles in the crystalline stru cture. (C) 2001 Elsevier Science B.V. All rights reserved.