title: "Heterogeneity within order" in metal-organic frameworks.
abstract: Metal-organic frameworks (MOFs) are constructed by linking inorganic units with organic linkers to make extended networks. Though more than 20 000 MOF structures have been reported most of these are ordered and largely composed of a limited number of different kinds building units, and very few have multiple different building units (heterogeneous). Although heterogeneity and multiplicity is a fundamental characteristic of biological systems, very few synthetic materials incorporate heterogeneity without losing crystalline order. Thus, the question arises: how do we introduce heterogeneity into MOFs without losing their ordered structure? This Review outlines strategies for varying the building units within both the backbone of the MOF and its pores to produce the heterogeneity that is sought after. The impact this heterogeneity imparts on the properties of a MOF is highlighted. We also provide an update on the MOF industry as part of this themed issue for the 150th anniversary of BASF.
authors.affiliation: Department of Chemistry, University of California-Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, and Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (USA), (O.M.Y.); King Abdulaziz City of Science and Technology, P.O. Box 6086, Riyadh 11442 (Saudi Arabia). furukawa@berkeley.edu.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Furukawa
authors.forename: Ulrich
authors.initials: U
authors.lastname: Müller
authors.forename: Omar M
authors.initials: OM
authors.lastname: Yaghi
keywords: defects; heterogeneity; industrial chemistry; metal-organic frameworks; secondary building units