Paper: Heterogeneity of Functional Groups in a Metal–Organic Framework Displays Magic Number Ratios
Authors: A. C.-H. Sue, R. V. Mannige, H. Deng, D. Cao, C. Wang, F. Gándara, J. F. Stoddart, S. Whitelam, and O. M. Yaghi
Citation: PNAS, 2015, 112, 5591-5596
DOI: 10.1073/pnas.1416417112
Abstract: Multiple organic functionalities can now be apportioned into nanoscale domains within a metal-coordinated framework, posing the following question: how do we control the resulting combination of “heterogeneity and order”? Here, we report the creation of a metal–organic framework, MOF-2000, whose two component types are incorporated in a 2:1 ratio, even when the ratio of component types in the starting solution is varied by an order of magnitude. Statistical mechanical modeling suggests that this robust 2:1 ratio has a nonequilibrium origin, resulting from kinetic trapping of component types during framework growth. Our simulations show how other “magic number” ratios of components can be obtained by modulating the topology of a framework and the noncovalent interactions between component types, a finding that may aid the rational design of functional multicomponent materials.