کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1406105 | 1501778 | 2013 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Structures of hydrazones, (E)-2-(1,3-benzothiazolyl)-NHNCHAr, [Ar = 4-(pyridin-2-yl)phenyl, pyrrol-2-yl, thien-2-yl and furan-2-yl]: Difference in conformations and intermolecular hydrogen bonding Structures of hydrazones, (E)-2-(1,3-benzothiazolyl)-NHNCHAr, [Ar = 4-(pyridin-2-yl)phenyl, pyrrol-2-yl, thien-2-yl and furan-2-yl]: Difference in conformations and intermolecular hydrogen bonding](/preview/png/1406105.png)
Structures of hydrazones, (E)-2-(1,3-benzothiazolyl)-NHNCHAr(Ar = pyridine-2-yl (1), pyrrol-2-yl (2), thien-2-yl (3) and furan-2-yl (4), prepared from 2-hydrazinyl-1,3-benzothiazole and ArCHO, followed by recrystallisation from alcohol solutions, are reported. No significant intramolecular hydrogen bonds are present in any of the four molecules. Different conformations were found between 2 and 3, on one hand and for 4, on the other. Thus for 4, the oxygen atom of the furanyl ring is on the same side of the molecule as is the sulfur atom of the benzothiazole unit, while in contrast, each of the heteroatoms of the thienyl and pyrrole rings lies on opposite sides to the benzothiazole sulphur atom. In addition to the conformational variations, differences are noted in the connections between molecules. Despite the presence in each case of N(hydrazono)H---N(benzothiazolo) intermolecular hydrogen bonds, molecules of 4 are linked into spiral chains, while molecules of 2 and 3 (and indeed all compounds having Ar = substituted phenyl) form symmetric dimers. Further intermolecular interactions, albeit weaker ones, are found in 2 [CH··N and NH··π], 3 [CH··π] and 4 [π··π], while dimers of 1 remain essentially free. Calculations carried out using the DFT(B3LYP)/6-311++G(d,p) method indicated that the conformations determined by crystallography for 2–4 were the more stable.
► Crystal structures of (E)-2-(1,3-benzothiazolyl)-NHNCHAr(Het) are reported.
► Differences in the supramolecular arrangements are observed.
► Calculated conformations are in agreement with crystallographic findings.
Journal: Journal of Molecular Structure - Volume 1036, 27 March 2013, Pages 19–27