Abstract A reaction between theophylline and (phenylthio)acetic acid in methanol results in the formation of organic cocrystal (phenylthio)acetic acid:theophylline. The characterization of the resulting cocrystal is performed using IR and 1 H NMR spectroscopy, TGA/DTA and X-ray crystallography. The crystal system of the cocrystal is monoclinic with space group P21/c and (Z = 8; Zʹ = 2). The unit cell parameters are a = 15.248(4) Å, b = 13.156(4) Å, c = 16.002(5) Å, and β = 106.059(4)°. The imidazole-carboxylic acid synthon is observed in the cocrystal. Intermolecular O–H…N hydrogen bonds and π–π interactions together play a vital role in the formation of the cocrystal and in the stabilization of the structure. Computational optimizations of the molecule were performed by density functional theory (DFT) using the B3LYP functional and Hartree–Fock (HF) level with a 6–311+ +G(d,p) basis set. In-vitro anti-microbial activities against some bacterial and fungal strains were investigated. Graphic Abstract The bandgap of the cocrystal is 3.5 times smaller than the starting compound.

中文翻译：

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(苯硫基)乙酸:茶碱共晶的合成、表征和生物活性

摘要 茶碱与（苯硫基）乙酸在甲醇中反应生成有机共晶（苯硫基）乙酸：茶碱。所得共晶的表征使用 IR 和 1 H NMR 光谱、TGA/DTA 和 X 射线晶体学进行。共晶的晶系为单斜晶系，空间群为P21/c，且（Z=8；Zʹ=2）。晶胞参数为 a = 15.248(4) Å、b = 13.156(4) Å、c = 16.002(5) Å 和 β = 106.059(4)°。在共晶中观察到咪唑-羧酸合成子。分子间 O-H…N 氢键和 π-π 相互作用在共晶的形成和结构的稳定中起着至关重要的作用。分子的计算优化通过密度泛函理论 (DFT) 使用 B3LYP 泛函和 Hartree-Fock (HF) 水平以及 6-311+ +G(d,p) 基组进行。研究了针对某些细菌和真菌菌株的体外抗微生物活性。图形摘要 共晶的带隙比起始化合物小 3.5 倍。