title: Probing Molecular Mechanisms of Self-Assembly in Metal-Organic Frameworks.
abstract: Metal-organic framework materials (MOFs) are a class of nanoporous materials, important to many applications (e.g., gas storage, separation), and their synthesis has received considerable attention. Yet, very little is known about the mechanisms of self-assembly of MOFs. Here, we provide molecular-level insights into the previously unexplored behavior of the self-assembly process, through molecular dynamics simulations, for an archetypal Zn-carboxylate MOF system exhibiting complex vertex topologies (e.g., paddle-wheel clusters). A key finding of this study is the characterization of a stochastic and multistage ordering process intrinsic to self-assembly of the Zn-carboxylate MOF system. A variety of transient intermediate structures consisting of various types of Zn-ion clusters and carboxylate-ligand coordination, and featuring a range of geometric arrangements, are observed during structural evolution. The general features deduced here for the mechanism of the self-assembly of this archetypal MOF system expose the complexities of the various molecular-level events that can occur during the early stages of this process spanning time scales of nano- to microseconds. More generally, we provide fundamental insights that elucidate key aspects of the early stages of the self-assembly mechanism for an important class of nanoporous materials, and of experimental studies exploring nucleation and growth processes in such materials.
authors.affiliation: Department of Chemistry, University of Calgary , 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Debasmita
authors.initials: D
authors.lastname: Biswal
authors.affiliation: Department of Chemistry, University of Calgary , 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Peter G
authors.identifier: 0000-0001-6270-663X
authors.initials: PG
authors.lastname: Kusalik
keywords: MOF self-assembly; Zn-carboxylate systems; molecular dynamics simulation; molecular-level mechanisms; multistage ordering; solvent dependence