%0 Journal Article
%T Temperature-Dependent Ordering of the Methyl Group in the Crystal Structure of 5-(2-Chlorophenyl)-7-ethyl-1H-thieno [2,3-E][1,4]diazepin-2(3H)-one
%A Grzegorz Dutkiewicz
%A Maciej Kubicki
%A Alaloor S. Dayananda
%A Hemmige S. Yathirajan
%A Andagar R. Ramesha
%J Crystals
%D 2012
%I MDPI AG
%R 10.3390/cryst2031347
%X 5-(2-Chlorophenyl)-7-ethyl-1 H-thieno[2,3-e][1,4]diazepin-2(3 H)-one, a close analogue of clotiazepam (full agonist at GABA receptor), crystallizes in monoclinic P2 1 /c space group with a = 15.6941(6) £¿, b = 10.7909(4) £¿, c = 8.6586(3) £¿, and ¦Â = 102.184(4)¡ã (at 125 K). Seven-Membered diazepine ring has approximate mirror plane of symmetry, planar thieno and phenyl rings are almost perpendicular to one another, dihedral angle between their mean planes is 84.11(5)¡ã. N¨CH¡¤¡¤¡¤O hydrogen bonds connect molecules into centrosymmetric dimers which are further expanded into 3D crystal structure with the help of weaker C¨CH¡¤¡¤¡¤O and C¨CH¡¤¡¤¡¤¦Ð interactions. The methyl group is disordered at room temperature, but it gets gradually ordered at lower temperatures and becomes fully ordered at approximately 200 K. The changes in structure with temperature were studied between 125 and 380 K. The unit cell volume¡ªas expected¡ªincreases almost monotonically when the temperature rises, but one of the parameters shortens significantly.
%K diazepines
%K hydrogen bonding
%K disorder
%K structural change
%U http://www.mdpi.com/2073-4352/2/3/1347