2-Propylamino-5-[4-(2-hydroxy-3,5-dichlorobenzylideneamino) phenyl]-1,3,4-thiadiazole: X-ray and DFT-calculated structures
作者:Nevin Süleymanoğlu、Reşat Ustabaş、Yelda Bingöl Alpaslan、Ufuk Çoruh、Sevgi Karakuş、Sevim Rollas
DOI:10.1007/s11224-009-9523-z
日期:2010.2
2-Propylamino-5-[4-(2-hydroxy-3,5-dichlorobenzylideneamino) phenyl]-1,3,4-thiadiazole, formulated as C18H16Cl2N4OS (I), was synthesized. The crystal and molecular structure of (I) have been determined by 1H-NMR, IR, and X-ray single crystal diffraction. The compound (I) crystallizes in the monoclinic, space group P2(1)/c with unit cell parameters a = 9.0576(2) Å, b = 24.3382(8) Å, c = 9.0585(2) Å, M r = 407.31, V = 1851.13(9) Å3, Z = 4, R 1 = 0.036, and wR 2 = 0.096. Molecular geometry from X-ray experiment of (I) in the ground state has been compared using the density functional method (B3LYP) with 6-31G(d) basis set. To determine conformational flexibility, molecular energy profile of (I) was obtained by semi-empirical (PM3) calculations with respect to selected degree of torsional freedom, which was varied from −180° to +180° in steps of 10°. The results are indicative that the Schiff base, which contains a thiadiazole ring, prefers to be in E-configuration. In addition, molecular electrostatic potential, frontier molecular orbitals, and natural bond orbitals analysis were performed by the B3LYP/6-31G(d) method.
2-丙基氨基-5-[4-(2-羟基-3,5-二氯苄叉氨基)苯基]-1,3,4-噻二唑(I)被合成。(I)的晶体和分子结构通过1H-NMR、IR和X射线单晶衍射测定。化合物(I)在单斜晶系中结晶,空间群为P2(1)/c,晶胞参数为a=9.0576(2)Å、b=24.3382(8)Å、c=9.0585(2)Å、M r=407.31、V=1851.13(9)Å3、Z=4、R 1=0.036和wR 2=0.096。使用密度泛函方法(B3LYP)和6-31G(d)基组对(I)在基态下的X射线实验的分子几何结构进行了比较。为了确定构象的灵活性,通过半经验(PM3)计算获得了(I)的分子能量分布,其中选择的扭转自由度从-180°到+180°,以10°为步长。结果表明,含有噻二唑环的席夫碱更倾向于处于E构象