Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
Phys Chem Chem Phys. 2010 Oct 28;12(40):13007-19. doi: 10.1039/c0cp00195c. Epub 2010 Aug 31.
The 1,3,4-thiadiazole derivatives (2-amino-1,3,4-thiadiazole, acetazolamide, sulfamethizole) have been studied experimentally in the solid state by (1)H-(14)N NQDR spectroscopy and theoretically by Density Functional Theory (DFT). The specific pattern of the intra and intermolecular interactions in 1,3,4-thiadiazole derivatives is described within the QTAIM (Quantum Theory of Atoms in Molecules)/DFT formalism. The results obtained in this work suggest that considerable differences in the NQR parameters permit differentiation even between specific pure association polymorphic forms and indicate that the stronger hydrogen bonds are accompanied by the larger η and smaller ν(-) and e(2)Qq/h values. The degree of π-electron delocalization within the 1,3,4-thiadiazole ring and hydrogen bonds is a result of the interplay between the substituents and can be easily observed as a change in NQR parameters at N atoms. In the absence of X-ray data NQR parameters can clarify the details of crystallographic structure revealing information on intermolecular interactions.
1,3,4-噻二唑衍生物（2-氨基-1,3,4-噻二唑、乙酰唑胺、磺胺甲恶唑）已通过（1）H-（14）N NQDR 光谱实验和密度泛函理论（DFT）理论进行了研究。在 QTAIM（分子中的原子量子理论）/DFT 形式中描述了 1,3,4-噻二唑衍生物中分子内和分子间相互作用的特定模式。这项工作的结果表明，NQR 参数的相当大差异允许甚至区分特定的纯缔合多晶形式，并表明较强的氢键伴随着较大的η和较小的ν（-）和 e（2）Qq/h 值。1,3,4-噻二唑环内和氢键中π电子离域的程度是取代基相互作用的结果，并且可以很容易地观察到 NQR 参数在 N 原子处的变化。在没有 X 射线数据的情况下，NQR 参数可以阐明晶体结构的细节，揭示关于分子间相互作用的信息。
