Leonard R. MacGillivray

Supramolecular Control of Reactivity in the Solid State: From Templates to Ladderanes to Metal−Organic Frameworks

We describe how reactivity can be controlled in the solid state using molecules and self-assembled metal-organic complexes as templates. Being able to control reactivity in the solid state bears relevance to synthetic chemistry and materials science. The former offers a promise to synthesize molecules that may be impossible to realize from the liquid phase while also taking advantage of the benefits of conducting highly stereocontrolled reactions in a solvent-free environment (i.e., green chemistry). The latter provides an opportunity to modify bulk physical properties of solids (e.g., optical properties) through changes to molecular structure that result from a solid-state reaction. Reactions in the solid state have been difficult to control owing to frustrating effects of molecular close packing. The high degree of order provided by the solid state also means that the templates can be developed to determine how principles of supramolecular chemistry can be generally employed to form covalent bonds. The paradigm of synthetic chemistry employed by Nature is based on integrating noncovalent and covalent bonds. The templates assemble olefins via either hydrogen bond or coordination-driven self-assembly for intermolecular [2 + 2] photodimerizations. The olefins are assembled within discrete, or finite, self-assembled complexes, which effectively decouples chemical reactivity from effects of crystal packing. The control of the solid-state assembly process affords the supramolecular construction of targets in the form of cyclophanes and ladderanes. The targets form stereospecifically, in quantitative yield, and in gram amounts. Both [3]- and [5]-ladderanes have been synthesized. The ladderanes are comparable to natural ladderane lipids, which are a new and exciting class of natural products recently discovered in anaerobic marine bacteria. The organic templates function as either hydrogen bond donors or hydrogen bond acceptors. The donors and acceptors generate cyclobutanes lined with pyridyl and carboxylic acid groups, respectively. The metal-organic templates are based on Zn(II) and Ag(I) ions. The reactivity involving Zn(II) ions is shown to affect optical properties in the form of solid-state fluorescence. The solids based on both the organic and metal-organic templates undergo rare single-crystal-to-single-crystal reactions. We also demonstrate how the cyclobutanes obtained from this method can be applied as novel polytopic ligands of metallosupramolecular assemblies (e.g., self-assembled capsules) and materials (e.g., metal-organic frameworks). Sonochemistry is also used to generate nanostructured single crystals of the multicomponent solids or cocrystals based on the organic templates. Collectively, our observations suggest that the organic solid state can be integrated into more mainstream settings of synthetic organic chemistry and be developed to construct functional crystalline solids.

Metal-organic frameworks : design and application

Preface. Contributors. 1 From Hofmann Complexes to Organic Coordination Networks (Makoto Fujita). 2 Insight into the Development of Metal-Organic Materials (MOMs): At Zeolite-like Metal-Organic Frameworks (ZMOFs) (Mohamed Eddaoudi and Jarrod F. Eubank). 3 Topology and Interpenetration (Stuart Batten). 4 Highly-Connected Metal-Organic Frameworks (Peter Hubberstey, Kiang Lin, Neil R. Champness and Martin Schroder). 5 Surface Pore Engineering of Porous Coordination Polymers (Sujit K. Ghosh and Susumu Kitagawa). 6 Rational Design of Non-centrosymmetric Metal-Organic Frameworks for Second-Order Nonlinear Optics (Wenbin Lin and Shuting Wu). 7 Selective Sorption of Gases and Vapors in Metal-Organic Frameworks (Hyumuk Kim, Hyungphil Chun and Kimoon Kim). 8 Hydrogen and Methane Storage in Metal Oorganic Frameworks (David J. Collins, Shengquin Ma and Hong-Cai Zhou). 9 Towards Mechanochemical Synthesis of Metal-Organic Frameworks: From Coordination Polymers and Lattice Inclusion Compounds to Porous Materials (Tomislav Fri i ). 10 Metal-Organic Frameworks with Photochemical Building Units (Saikat Dutta, Ivan F. Georgiev and Leonard R. MacGillivray). 11 Molecular Modeling of Adsorption and Diffusion in Metal-Organic Frameworks (Randall Q. Snurr, A. Ozgur Yazaydin, David Dubbeldam and Houston Frost). Index.

STRUCTURAL CLASSIFICATION AND GENERAL PRINCIPLES FOR THE DESIGN OF SPHERICAL MOLECULAR HOSTS

Cryptands, carcerands, polyoxometalates, and molecular capsules are cagelike hosts that complex guests through encapsulation. Following the discovery of a nanometer scale supramolecular shell-like spheroid, these and other shell-like hosts were structurally classified. Their frameworks may be catalogued according to principles of solid geometry. This has led to the identification of hosts that have not yet been synthesized or discovered (such as the cuboctahedron shown; X=O, S) and should lead to the design of additional container assemblies.

Inverted metal-organic frameworks: solid-state hosts with modular functionality

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.

Organic synthesis in the solid state via hydrogen-bond-driven self-assembly.

This Perspective describes how chemists can control intermolecular [2 + 2] photodimerizations in the solid state using small molecules as linear templates. The templates assemble olefins into positions for the reaction via hydrogen-bond-driven self-assembly. We attach functional groups to the olefins that complement hydrogen bond donor and acceptor groups of the templates. The resulting cyclobutane-based products form stereospecifically, quantitatively, and in gram amounts. The templates are used to direct the formation of a [2.2]paracyclophane and ladderanes. The organic solid state is an exciting medium within which to control chemical reactivity since it is possible to synthesize, or construct, molecules that may be, otherwise, unobtainable from solution. The products form with a high degree of stereocontrol provided by a crystal lattice. The critical covalent-bond-forming process also occurs in a solvent-free environment. That molecules are virtually frozen in position in a solid also means that this methodology enables chemists to employ principles of molecular recognition and self-assembly to direct and conduct organic synthesis.

Metal-mediated reactivity in the organic solid state: from self-assembled complexes to metal-organic frameworks.

The purpose of this tutorial review is to address the use of metal ions to mediate reactions in the organic solid state. We describe metal complexes and coordination networks that facilitate dimerizations, oligomerizations and polymerizations of olefins and acetylenes via irradiation (e.g. ultraviolet (UV) and (60)Co gamma-rays) and thermal annealing. We show how metal ions can be utilized to direct the formation of polymers and molecules. We also describe how supramolecular chemistry has recently influenced dimerization processes in self-assembled metal-organic solids.

Single-crystal-to-single-crystal [2 + 2] photodimerizations: from discovery to design

Abstract The purpose of this review is to address fundamentals and applications of single-crystal-to-single-crystal (SCSC) reactions, based on the [2 + 2] photodimerization. An overview of SCSC [2 + 2] photodimerizations, which comprise single- and multi-component solids, will be given. We reveal that materials that exhibit SCSC reactivity can be considered to have been achieved via either discovery or design. We suggest that SCSC [2 + 2] photodimerizations, if generally achieved, could provide new avenues to control bulk physical properties of solid-state materials.

Strukturelle Klassifizierung von sphärischen molekularen Wirten und allgemeine Prinzipien für ihren Entwurf

Nach den Prinzipien der Geometrie der Korper konnen Kryptanden, Carceranden, Polyoxometallate und molekulare Kapseln strukturell klassifiziert werden. Diese kafigartigen Wirtverbindungen komplexieren die Gaste durch Einkapseln. Nach der Entdeckung eines supramolekularen, kafigartigen Spharoids im Nanometermasstab wurden die Geruste dieses und anderer Wirte katalogisiert. Dies bildete die Grundlage fur das Auffinden neuer Wirte, die bislang noch nicht synthetisiert oder entdeckt worden sind (wie das im Bild gezeigte Kuboktaeder; X = O, S), und sollte auserdem zum Entwurf weiterer Verbindungen mit Behaltereigenschaften fuhren.

An Inverted Metal‐Organic Framework with Compartmentalized Cavities Constructed by Using an Organic Bridging Unit Derived from the Solid State

Porous crystalline solids that employ metal-organic components as building blocks, where a rigid, linear organic bridge propagates the coordination geometry of a metal node in one-, two-, or threedimensions, are attracting much interest.[1±3] Such metal ± organic frameworks (MOFs) are designed to exhibit properties that mimic, and improve upon, more conventional porous solids, such as zeolites[4] and mesoporous materials (MCMs).[5] Many porous MOFs, however, have fallen short, in contrast to zeolites and MCMs, as robust porous solids.[2, 6] Interpenetration[6] and framework fragility[2] have hampered progress such that host cavities tend to selfinclude while guest removal often results in a collapse of host structure. Recently, however, such problems of interpenetration and framework fragility have been largely circumvented by using metal clusters, as secondary building units (SBUs), for host design.[7] SBUs (e.g. metal carboxylates) reduce the likelihood of interpenetration owing to their large sizes which can preclude filling of void spaces,[8] producing stable, porous solids able to support inclusion and catalysis.[1a±c] Although SBUs have been successfully employed for the construction of MOFs with stable pores, it can be difficult, in contrast to MCMs,[5, 9] to line the interiors of such solids with organic groups since an elaborate covalent synthesis of a linear organic bridge is often required to introduce simple (e.g. -Me) and diverse (e.g. chiral) functional groups. With this in mind, it has occurred to us that one way to circumvent this problemmay be to invert the structural role[10] of the SBU and linear organic bridge such that the SBU serves as a linear bridge and the organic ligand serves as a node. In this design, the bonds of the SBU that support the framework are minimized (i.e. two) such that the remaining coordination sites of the SBU may be filled with organic ligands that decorate the interior of the framework. Moreover, such an inverted metal-organic framework (IMOF) would enable the second sphere of a SBU to line the walls of a host, in contrast to a covalent synthesis, supramolecularly[11] where convergent[12] terminal groups may be tailored to define structure and recognition properties of the solid. Herein, we describe initial results of a strategy for the construction of such a porous IMOF that employs a molecule

Supramolecular Catalysis in the Organic Solid State through Dry Grinding

[Figure Presented] Chemical mechanics: Hydrogen-bonddriven self-assembly and mechanochemistry are used to facilitate supramolecular catalysis in the solid state. Mortar-andpestle grinding proves to be an efficient means to achieve co-crystal formation and turnover using a physical mixture composed of an olefin and catalytic amounts of a ditopic template (see scheme).