Amount Awarded: $22,500
M-MOF-74 and its related analogs are widely studied metal-organic frameworks (MOFs) and are industrially promising for adsorption-based applications. M-MOF-74 is characterized by a high density of under-coordinated metal sites that are arranged in the direction of one-dimensional channels. To take advantage of M-MOF-74's one-dimensional porosity, which can make it an ideal candidate material for membrane-based separations, the nucleation and growth processes must be controlled to result in ideally-shaped MOF crystals. The mechanisms of M-MOF-74 nucleation and growth are, however, completely unknown. Developing an approach to filling this crucial gap in fundamental knowledge has motivated this proposal. In this project, we propose a combined experimental and simulation study to measure and compute nucleation kinetics. We introduce an implementation of replica exchange transition interface sampling (RETIS) that can work seamlessly with moves generated by Monte Carlo simulations to capture MOF linker protonation and deprotonation, an important factor in nucleation kinetics. Combining RETIS with tailor-made force fields that we have developed, we will be able predict the rates of formation of precursor MOF clusters. By resolving computed predictions with experimentally measured rates, we will develop a generalizable technique capable of predicting likely nucleation pathways and their associated rates at given reaction conditions.