Groth's Original Concomitant Polymorphs Revisited

The search for the third concomitant polymorphic form γ of 1,3-bis(m-nitrophenyl)urea that was
described in 1899, but not reported in more recent papers, has revealed a new polymorphic form, δ, and a monohydrate
form of the material in addition to its already known α and β forms. It is suggested that the monohydrate is actually
the literature-reported γ form. Both new forms have been characterized and compared to α and β forms by a variety
of methods including thermal methods, FT-IR, and cross polarization/magic angle spinning (CPMAS) NMR
spectroscopy, single-crystal X-ray structure determination, and lattice energy calculations.

针对1,3-二(间硝基苯基)脲的第三种伴随多晶型γ相的追溯研究，该晶型于1899年首次被报道，但后续近年文献中均未再提及相关内容。本次研究在该探索过程中，除已为人知的α与β晶型外，还发现了一种新的多晶型δ相以及该物质的一水合物晶型。经分析论证，该一水合物晶型实际上正是文献中所记载的γ相。本研究通过多种表征手段对这两种新晶型进行了系统表征，并与已知的α、β晶型开展对比分析，所用方法涵盖热分析技术、傅里叶变换红外光谱（FT-IR）、交叉极化/魔角旋转（CPMAS）核磁共振波谱、单晶X射线结构测定以及晶格能量计算。