A new 1:1 cocrystal (l‐Asc–Pic) of l‐ascorbic acid (vitamin C) with picolinic acid was prepared as a powder and as single crystals. The crystal structure was solved and refined from single‐crystal X‐ray diffraction (SCXRD) data collected at 293 (2) and 100 (2) K. The samples of the l‐Asc–Pic cocrystal were characterized by elemental (HCNS) analysis and titrimetric methods, TG/DTG/DSC, and IR and Raman spectroscopy. The asymmetric unit comprises a picolinic acid zwitterion and an l‐ascorbic acid molecule. The stabilization energy of intermolecular interactions involving hydrogen bonds, the vibrational spectrum and the energies of the frontier molecular orbitals were calculated using the GAUSSIAN09 and the CrystalExplorer17 programs. The charge distribution on the atoms of the l‐Asc–Pic cocrystal, l‐ascorbic acid itself and its 12 known cocrystals (structures from Version 5.40 of the Cambridge Structural Database) were calculated by the methods of Mulliken, Voronoi and Hirshfeld charge analyses (ADF) at the bp86/TZ2P+ level of theory. The total effective charges and conformations of the l‐ascorbic acid molecules in the new and previously reported cocrystals were compared with those of the two symmetry‐independent molecules in the crystals of l‐ascorbic acid. A correlation between molecular conformation and its effective charge is discussed.

中文翻译：

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l-抗坏血酸与吡啶甲酸的共晶体：OH-O…O，NH-O和CHH-O氢键和l-抗坏血酸构象在结构稳定中的作用

一个新的1：1的共晶体（升的-Asc-PIC）升抗坏血酸（维生素C）与吡啶甲酸制备为粉末和作为单晶。在293（2）和100（2）K。的的样品收集到的晶体结构解析和从单晶X射线衍射精制（SCXRD）数据升-Asc-PIC共晶体进行表征通过元素（HCNS）分析和滴定法，TG / DTG / DSC以及IR和拉曼光谱。不对称单元包括吡啶甲酸两性离子和升抗坏血酸分子。分子间相互作用的涉及氢键的稳定能，振动谱和前沿分子轨道的能量用GAUSSIAN09和分子动力学计算。CrystalExplorer17程序。上的原子的电荷分布升-Asc-PIC共晶体，升抗坏血酸本身和它的12个已知的共结晶（从剑桥结构数据库的5.40版的结构）通过马利肯，沃罗诺伊和Hirshfeld电荷分析的方法（计算ADF）的理论水平为bp86 / TZ2P +。将新的和先前报道的共晶体中的l抗坏血酸分子的总有效电荷和构象与l抗坏血酸晶体中两个独立于对称性的分子的总电荷和构象进行了比较。讨论了分子构象与其有效电荷之间的相关性。