Dynamic Equilibrium of a Supramolecular Dimeric Rhomboid and Trimeric Hexagon and Determination of Its Thermodynamic Constants
作者:Takuya Yamamoto、Atta M. Arif、Peter J. Stang
DOI:10.1021/ja0302984
日期:2003.10.1
concentration- and temperature-dependent dynamic equilibrium. The two structures are characterized by multinuclear NMR and ESI-MS. Extensive study of the dynamic equilibrium of the two species in solution is performed to obtain its thermodynamic properties. By varying the ionic strength, mu, of the solutions, the true thermodynamic equilibrium constant, K, is determined at each experimental temperature
超分子二聚菱形及其三聚体对应物六边形是通过自组装的定向键合方法设计生成的。由 Pt 配位形成的不同大小的超分子大环经历浓度和温度相关的动态平衡。这两种结构通过多核 NMR 和 ESI-MS 表征。对溶液中两种物质的动态平衡进行了广泛的研究,以获得其热力学性质。通过改变溶液的离子强度 mu,在每个实验温度下确定真正的热力学平衡常数 K(K(253) = 36 +/- 7,K(273) = 18 +/- 6,K (293) = 10 +/- 3,K(313) = 9 +/- 2,K(333) = 5 +/- 2,以及 K(353) = 3.0 +/- 0.2)。通过将这些在相应温度下的真实 K 值应用于货车' 用熵项扩展的 t Hoff 方程,确定平衡的标准焓和熵变化:Delta H 度 = -18 +/- 1 kJ mol(-1) 和 Delta S 度 = -43 +/- 4 J mol(-1)