Chemical Sciences Division, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California , Berkeley, California 94720, United States.
Anal Chem. 2016 Jul 5;88(13):6923-9. doi: 10.1021/acs.analchem.6b01684. Epub 2016 Jun 14.
The entropic and enthalpic driving forces for encapsulation versus sequential exterior guest binding to the Ga4L6 supramolecular host in solution are very different, which significantly complicates the determination of these thermodynamic parameters. The simultaneous use of complementary techniques, such as NMR, UV-vis, and isothermal titration calorimetry, enables the disentanglement of such multiple host-guest interactions. Indeed, data collected by each technique measure different components of the host-guest equilibria and together provide a complete picture of the solution thermodynamics. Unfortunately, commercially available programs do not allow for global analysis of different physical observables. We thus resorted to a novel procedure for the simultaneous refinement of multiple parameters (ΔG°, ΔH°, and ΔS°) by treating different observables through a weighted nonlinear least-squares analysis of a constrained model. The refinement procedure is discussed for the multiple binding of the Et4N(+) guest, but it is broadly applicable to the deconvolution of other intricate host-guest equilibria.
在溶液中，Ga4L6超分子主体对封装与顺序外部客体结合的熵和焓驱动力非常不同，这使得这些热力学参数的确定变得非常复杂。同时使用互补技术，如 NMR、UV-vis 和等温滴定量热法，可以解开这种多重主体-客体相互作用。事实上，每种技术收集的数据测量了主体-客体平衡的不同组成部分，共同提供了溶液热力学的完整图景。不幸的是，商业上可用的程序不允许对不同的物理可观测量进行全局分析。因此，我们通过对约束模型进行加权非线性最小二乘分析来处理不同的可观测量，从而开发了一种新的同时精修多个参数（ΔG°、ΔH°和ΔS°）的新方法。讨论了该方法在多个 Et4N(+)客体结合中的应用，但它也广泛适用于其他复杂主体-客体平衡的解卷积。
