International Collaboration in Chemistry: Aqueous Host-Guest Chemistry with Self-Assembling Metal-templated Cages

明尼苏达大学的Laura Gagliardi(PI)和Christopher J.Cramer(co-Pi)教授获得了国际化学合作(ICC)奖，在化学系的大分子、超分子和纳米化学(MSN)计划和化学理论、模型和计算方法计划(CTMCM)的共同支持下，将与英国剑桥大学化学系的Jonathan Nitschke教授一起从事研究，以评估影响水中中小有机分子自组装主客体化学中结合和识别的基本因素金属模板笼子。通过利用模拟和实验之间的螺旋反馈，他们将识别络合物中关键的空间和静电相互作用，对这些相互作用的控制将有助于改进的主客体组合的合理设计。将采用基于量子力学和分子力学的理论模型。量子力学模型将被用来用基准数据来补充实验，以选择经典的机械力场，还将被用来计算光谱数据(例如，核磁共振和UV/Vis)，以便与实验的主客体组合进行比较。经典的机械力场模型将被用来模拟主客体组合的动力学行为，并用于预测与水结合事件相关的平均力势。有了足够的验证数据，将在电子设计中进行努力，目标是将合成努力集中在显示出更高的选择性和结合效率的主-客体组合上。分子笼已被证明可以稳定不稳定的分子，如白磷，一种自燃和剧毒的元素形式。笼子还可以通过与高能活性中间体结合来选择性地加速(催化)反应，从而降低它们的能量。为了扩大这些用途和开发新的用途，必须从根本上了解被包裹的分子与它们的宿主之间的弱相互作用。这一合作研究项目将使一个美英团队能够将理论和实验结合起来，以了解这种“主-客化学”的基本原理，目标是能够为做梦也想不到的应用设计新的笼子。

With an International Collaborations in Chemistry (ICC) award, Professors Laura Gagliardi (PI) and Christopher J. Cramer (co-PI) of the University of Minnesota, supported jointly by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program and the Chemical Theory, Models and Computational Methods Program (CTMCM) in the Division of Chemistry as well as the NSF Office of International Science and Engineering (OISE), will engage in research with Professor Jonathan Nitschke of the Department of Chemistry, Cambridge University, United Kingdom, to assess the fundamental factors affecting binding and recognition in the aqueous host-guest chemistry of small to moderate-sized organic molecules inside self-assembling, metal-templated cages. By taking advantage of spiral feedback between modeling and experiment, they will identify key steric and electrostatic interactions in the complexes, the control of which will facilitate the rational design of improved host-guest combinations. Theoretical models based on both quantum and molecular mechanics will be employed. Quantum mechanical models will be employed to supplement experiment with benchmark data for the selection of classical mechanical force fields and also be used to compute spectral data (e.g., NMR and UV/Vis) in order to compare to experimental host-guest combinations. Classical mechanical force field modeling will be used to simulate the dynamical behavior of host-guest combinations and for the prediction of potentials of mean force associated with aqueous binding events. With sufficient validating data in hand, in silico design efforts will be undertaken with the goal of focusing synthetic efforts on host-guest combinations showing enhanced selectivity and binding efficiencies.Molecular cages have been shown to stabilize unstable molecules, such as white phosphorus, a spontaneously-flammable and highly toxic form of the element. Cages can also selectively speed up (catalyze) reactions by binding to high-energy reactive intermediates, thus lowering their energies. In order to extend these uses and develop new ones, fundamental understanding must be gained as to the weak interactions between encapsulated molecules and their hosts. This collaborative research project will allow a US-UK team to combine theory and experiment to come to an understanding of the fundamentals of this 'host-guest chemistry' with the goal of being able to design new cages for applications as yet undreamt-of.