Henriques M S C, Del Amparo R, Pérez-Álvarez D, Nogueira B A, Rodríguez-Argüelles M C, Paixão J A
CFisUC, Department of Physics, University of Coimbra, P-3004-516, Coimbra, Portugal.
Departamento de Química Inorgánica, Universidade de Vigo, 36310 Vigo, Spain.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Feb 5;172:189-198. doi: 10.1016/j.saa.2016.02.012. Epub 2016 Feb 19.
The synthesis of a new hydrazone, 2-oxoacenaphthylen-1(2H)-ylidene nicotinohydrazide, and its structural and spectroscopic characterization is reported. The obtained powder was recrystallized from DMSO and ethanol that afforded small crystals used for single-crystal X-ray diffraction studies. The compound was found to crystallize in two polymorphs, depending on the crystallization conditions. One of the polymorphs (form I) crystallizes in the centrosymmetric P2/c monoclinic space group, the other (form II) crystallizes in the non-centrosymmetric, but achiral, orthorhombic space group P222. Conformation of the molecules is similar in both polymorphs, but the network of weak intermolecular interactions determining the crystal packing is different. In form II an additional C-H⋯O bond connects molecules related by the screw-axis running parallel to the a-axis. Crystals of both polymorphs were also screened by FT-IR and Raman microscopy; a detailed analysis of the spectra and comparison with those of the isolated molecule calculated by ab-initio HF/MP2 and DFT/B3LYP methods using a correlation consistent cc-pVDZ basis set is presented. In addition, UV-vis and NMR studies were performed in solution.
报道了一种新型腙（2-氧代苊烯-1(2H)-亚基烟酰肼）的合成及其结构和光谱表征。将所得粉末从二甲基亚砜和乙醇中重结晶，得到用于单晶X射线衍射研究的小晶体。发现该化合物根据结晶条件以两种多晶型物结晶。其中一种多晶型物（晶型I）在中心对称的P2/c单斜空间群中结晶，另一种（晶型II）在非中心对称但非手性的正交空间群P222中结晶。两种多晶型物中分子的构象相似，但决定晶体堆积的弱分子间相互作用网络不同。在晶型II中，一个额外的C-H⋯O键连接由平行于a轴的螺旋轴相关的分子。还用傅里叶变换红外光谱（FT-IR）和拉曼显微镜对两种多晶型物的晶体进行了筛选；给出了光谱的详细分析，并与使用相关一致的cc-pVDZ基组通过从头算HF/MP2和DFT/B3LYP方法计算的孤立分子的光谱进行了比较。此外，还在溶液中进行了紫外可见光谱和核磁共振研究。
