Heterogeneity of functional groups in a metal-organic framework displays magic number ratios.
Publication Type:Journal Article
Source:Proc Natl Acad Sci U S A, Volume 112, Issue 18, p.5591-6 (2015)
Keywords:Algorithms, Computer Simulation, Crystallography, X-Ray, Kinetics, Magnetic Resonance Spectroscopy, Metals, Models, Chemical, Models, Molecular, Molecular Structure, Monte Carlo Method, Organometallic Compounds, Solutions, Thermodynamics
<p>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.</p>