Coordination Chemistry Reviews 246 (2003) 169–184 Inverted metal–organic frameworks: solid-state hosts with modular functionality Giannis S. Papaefstathiou, Leonard R. MacGillivray ∗ Department of Chemistry, University of Iowa, Iowa City, IA 52245-1294, USA Received 13 March 2003; accepted 17 June 2003 Contents Abstract ................................................................................................................................ 169 1. Introduction ....................................................................................................................... 169 2. Overview .......................................................................................................................... 170 3. Functionalization of MCMs and zeolites .............................................................................................. 170 4. Functionalization of metal–organic frameworks ....................................................................................... 171 4.1. Synthetic strategies .......................................................................................................... 171 4.1.1. Single metal ion as node ............................................................................................. 171 4.1.2. Secondary building unit as node ...................................................................................... 173 4.2. Pre-framework synthesis and covalent functionalization ............................................................................ 176 5. Inverted metal organic frameworks ................................................................................................... 176 5.1. Single metal ion as linear bridge .............................................................................................. 176 5.2. Secondary building unit as linear bridge ........................................................................................ 180 5.3. Our approach ............................................................................................................... 181 6. Summary and outlook .............................................................................................................. 183 Acknowledgements ...................................................................................................................... 183 References ............................................................................................................................. 183 Abstract Metal–organic frameworks (MOFs) are crystalline inorganic–organic hybrid materials that consist of metal ions and organic molecules connected in space to produce an infinite one-, two-, or three-dimensional framework. The modularity of MOFs, specifically, the ability to modify the organic and/or inorganic components, offers a ready means to modify and control properties of such materials (e.g. inclusion, magnetism). This review highlights the design and synthesis of cavity-containing and porous MOFs with emphasis on methods that enable the functionalization of interior void spaces with organic groups. A relatively new class of MOFs, known as inverted metal–organic frameworks (IMOFs), which enables organic functionalization using principles of supramolecular chemistry, is discussed. We also briefly outline methods to functionalize the interior spaces of mesoporous materials (MCMs) and zeolites, and suggest that MOFs offer a diverse space within which to place a wide range of organic functionalities. © 2003 Elsevier B.V. All rights reserved. Keywords: Metal–organic framework; Modular functionality; Solid-state host 1. Introduction Two decades ago the border between solid-state chem- istry, which was largely orientated towards materials sci- ∗ Corresponding author. Tel.: +1-319-335-3504; fax: +1-319-335-1270. E-mail address: len-macgillivray@uiowa.edu (L.R. MacGillivray). ence, and molecular chemistry, which was largely orientated towards chemical reactivity and catalysis, was unambigu- ous. During the last two decades, a new field has developed, which bridges the gap between the solid-state chemistry and molecular chemistry, known as molecular materials science [1–3]. In contrast to solid-state inorganic materials, which are based on atoms, solid-state molecular materials are based 0010-8545/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0010-8545(03)00122-X