晶态、无定形态同质异形配合物的合成及转化热力学研究

Synthesis and Conversion Thermodynamic Study of Crystalline and Amorphous Polymorphous Complexes

摘要: 利用不同的方法制备出基于尿刊酸和ZnSO₄∙7H₂O的晶态(CryZn)和无定形态(AmZn)两种同质异形固体。利用X-射线单晶衍射(XRD)、X-射线粉末衍射(XRPD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、紫外分光光度法等技术和方法进行了表征，比较了不同固态形式的微观结构、形貌、摩尔电导率和平衡溶解度，并推导计算了水溶液中晶态配合物向无定形态的转化温度和热力学参数。结果表明CryZn与AmZn在水中的转化温度为308.3 K，CryZn向AmZn转变属焓驱动过程，温度越高，越不利于转化的发生。

Abstract: Two solid forms of crystalline (CryZn) and amorphous (AmZn) complexes based on urocanic acid and ZnSO₄∙7H₂O were prepared by different approaches. X-ray single crystal diffraction (XRD), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet spectrophotometry techniques were applied to characterize and compare their differences on microstructures, morphology, molar conductivities and equilib-rium solubilities. The conversion temperature and thermodynamic parameters in aqueous solution of the crystalline complex to the amorphous form were also calculated. The results show that the conversion temperature of CryZn and AmZn is 308.3 K, and the conversion of CryZn to AmZn belongs to the enthalpy control, that is, the higher the temperature is, the more unfavorable the transformation occurs.