Publications
39 results found
Pugh CJ, Santolini V, Greenaway RL, et al., 2018, Cage doubling: solvent-mediated re-equilibration of a [3+6] prismatic organic cage to a large [6+12] truncated tetrahedron, Crystal Growth and Design, Vol: 18, Pages: 2759-2764, ISSN: 1528-7483
We show that a [3 + 6] trigonal prismatic imine (a) cage can rearrange stoichiometrically and structurally to form a [6 + 12] cage (b) with a truncated tetrahedral shape. Molecular simulations rationalize why this rearrangement was only observed for the prismatic [3 + 6] cage TCC1 but not for the analogous [3 + 6] cages, TCC2 and TCC3. Solvent was found to be a dominant factor in driving this rearrangement.
Greenaway RL, Holden D, Eden EGB, et al., 2017, Understanding gas capacity, guest selectivity, and diffusion in porous liquids, Chemical Science, Vol: 8, Pages: 2640-2651, ISSN: 2041-6520
Porous liquids are a new class of material that could have applications in areas such as gas separation and homogeneous catalysis. Here we use a combination of measurement techniques, molecular simulations, and control experiments to advance the quantitative understanding of these liquids. In particular, we show that the cage cavities remain unoccupied in the absence of a suitable guest, and that the liquids can adsorb large quantities of gas, with gas occupancy in the cages as high as 72% and 74% for Xe and SF6, respectively. Gases can be reversibly loaded and released by using non-chemical triggers such as sonication, suggesting potential for gas separation schemes. Diffusion NMR experiments show that gases are in dynamic equilibrium between a bound and unbound state in the cage cavities, in agreement with recent simulations for related porous liquids. Comparison with gas adsorption in porous organic cage solids suggests that porous liquids have similar gas binding affinities, and that the physical properties of the cage molecule are translated into the liquid state. By contrast, some physical properties are different: for example, solid homochiral porous cages show enantioselectivity for chiral aromatic alcohols, whereas the equivalent homochiral porous liquids do not. This can be attributed to a loss of supramolecular organisation in the isotropic porous liquid.
Chintalapudi V, Galvin EA, Greenaway RL, et al., 2016, Combining cycloisomerization with trienamine catalysis: a regiochemically flexible enantio- and diastereoselective synthesis of hexahydroindoles, CHEMICAL COMMUNICATIONS, Vol: 52, Pages: 693-696, ISSN: 1359-7345
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- Citations: 27
Giri N, Del Popolo MG, Melaugh G, et al., 2015, Liquids with permanent porosity, Nature, Vol: 527, Pages: 216-220, ISSN: 0028-0836
Porous solids such as zeolites1 and metal–organic frameworks2,3 are useful in molecular separation and in catalysis, but their solid nature can impose limitations. For example, liquid solvents, rather than porous solids, are the most mature technology for post-combustion capture of carbon dioxide because liquid circulation systems are more easily retrofitted to existing plants. Solid porous adsorbents offer major benefits, such as lower energy penalties in adsorption–desorption cycles4, but they are difficult to implement in conventional flow processes. Materials that combine the properties of fluidity and permanent porosity could therefore offer technological advantages, but permanent porosity is not associated with conventional liquids5. Here we report free-flowing liquids whose bulk properties are determined by their permanent porosity. To achieve this, we designed cage molecules6,7 that provide a well-defined pore space and that are highly soluble in solvents whose molecules are too large to enter the pores. The concentration of unoccupied cages can thus be around 500 times greater than in other molecular solutions that contain cavities8,9,10, resulting in a marked change in bulk properties, such as an eightfold increase in the solubility of methane gas. Our results provide the basis for development of a new class of functional porous materials for chemical processes, and we present a one-step, multigram scale-up route for highly soluble ‘scrambled’ porous cages prepared from a mixture of commercially available reagents. The unifying design principle for these materials is the avoidance of functional groups that can penetrate into the molecular cage cavities.
Campbell CD, Greenaway RL, Holton OT, et al., 2015, Ynamide Carbopalladation: A Flexible Route to Mono-, Bi- and Tricyclic Azacycles, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 21, Pages: 12627-12639, ISSN: 0947-6539
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- Citations: 40
Briggs ME, Slater AG, Lunt N, et al., 2015, Dynamic flow synthesis of porous organic cages, CHEMICAL COMMUNICATIONS, Vol: 51, Pages: 17390-17393, ISSN: 1359-7345
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- Citations: 44
Campbell CD, Greenaway RL, Holton OT, et al., 2014, Palladium-catalyzed cyclization of bromoenynamides to tricyclic azacycles: synthesis of trikentrin-like frameworks, CHEMICAL COMMUNICATIONS, Vol: 50, Pages: 5187-5189, ISSN: 1359-7345
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- Citations: 24
Greenaway RL, Campbell CD, Chapman HA, et al., 2012, Reductive Cyclization of Bromoenynamides with Alcohols as Hydride Source: Synthesis and Reactions of 2-Amidodienes, ADVANCED SYNTHESIS & CATALYSIS, Vol: 354, Pages: 3187-3194, ISSN: 1615-4150
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- Citations: 36
Greenaway RL, Campbell CD, Holton OT, et al., 2011, Palladium-Catalyzed Cascade Cyclization of Ynamides to Azabicycles, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 17, Pages: 14366-14370, ISSN: 0947-6539
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- Citations: 48
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