Department of Chemistry, University of California, Berkeley and Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, USA.
J Am Chem Soc. 2010 Jan 27;132(3):1005-9. doi: 10.1021/ja9056739.
NMR, UV-vis, and isothermal titration calorimetry (ITC) measurements probe different aspects of competing host-guest equilibria as simple alkylammonium guest molecules interact with both the exterior (ion-association) and interior (encapsulation) of the Ga(4)L(6) supramolecular assembly in water. Data obtained by each independent technique measure different components of the host-guest equilibria and only when analyzed together does a complete picture of the solution thermodynamics emerge. Striking differences between the internal and external guest binding are found. External binding is enthalpy driven and mainly due to attractive interactions between the guests and the exterior surface of the assembly while encapsulation is entropy driven as a result of desolvation and release of solvent molecules from the host cavity.
NMR、UV-vis 和等温滴定量热法（ITC）测量探测了不同的竞争主客体平衡方面，因为简单的烷基铵客体分子与 Ga(4)L(6) 超分子组装体在水中的外部（离子缔合）和内部（包合）相互作用。每种独立技术获得的数据测量了主客体平衡的不同组成部分，只有当它们一起分析时，才能得出溶液热力学的完整图景。发现内部和外部客体结合之间存在显著差异。外部结合是焓驱动的，主要是由于客体和组装体外部表面之间的吸引力相互作用，而包合是熵驱动的，因为溶剂分子从主体腔中去溶剂化和释放。
