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2. Threaded rings that swim in excitable media

Author

Cincotti, Antonio, Maucher, Fabian, Evans, David, Chapin, Brette M., Horner, Kate, Bromley, Elizabeth, Lobb, Andrew, Steed, Jonathan W., and Sutcliffe, Paul

Subjects
Nonlinear Sciences - Pattern Formation and Solitons, Condensed Matter - Soft Condensed Matter
Abstract

Cardiac tissue and the Belousov-Zhabotinsky reaction provide two notable examples of excitable media that support scroll waves, in which a filament core is the source of spiral waves of excitation. Here we consider a novel topological configuration in which a closed filament loop, known as a scroll ring, is threaded by a pair of counter-rotating filaments that are perpendicular to the plane of the ring and end on the boundary of a thin medium. We simulate the dynamics of this threaded ring (thring) in the photosensitive Belousov-Zhabotinsky excitable medium, using the modified Oregonator reaction-diffusion equations. These computations reveal that the threading topology induces an exotic motion in which the thring swims in the plane of the ring. We propose a light templating protocol to create a thring in the photosensitive Belousov-Zhabotinsky medium and provide experimental confirmation that this protocol indeed yields a thring., Comment: 8 pages, 6 figures. Version to appear in PRL

Published
2019
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3. Confronting Racism in Chemistry Journals

Author

Burrows, Cynthia J, Huang, Jiaxiang, Wang, Shu, Kim, Hyun Jae, Meyer, Gerald J, Schanze, Kirk, Lee, T Randall, Lutkenhaus, Jodie L, Kaplan, David, Jones, Christopher, Bertozzi, Carolyn, Kiessling, Laura, Mulcahy, Mary Beth, Lindsley, Craig W, Finn, MG, Blum, Joel D, Kamat, Prashant, Choi, Wonyong, Snyder, Shane, Aldrich, Courtney C, Rowan, Stuart, Liu, Bin, Liotta, Dennis, Weiss, Paul S, Zhang, Deqing, Ganesh, Krishna N, Atwater, Harry A, Gooding, J Justin, Allen, David T, Voigt, Christopher A, Sweedler, Jonathan, Schepartz, Alanna, Rotello, Vincent, Lecommandoux, Sébastien, Sturla, Shana J, Hammes-Schiffer, Sharon, Buriak, Jillian, Steed, Jonathan W, Wu, Hongwei, Zimmerman, Julie, Brooks, Bryan, Savage, Phillip, Tolman, William, Hofmann, Thomas F, Brennecke, Joan F, Holme, Thomas A, Merz, Kenneth M, Scuseria, Gustavo, Jorgensen, William, Georg, Gunda I, Wang, Shaomeng, Proteau, Philip, Yates, John R, Stang, Peter, Walker, Gilbert C, Hillmyer, Marc, Taylor, Lynne S, Odom, Teri W, Carreira, Erick, Rossen, Kai, Chirik, Paul, Miller, Scott J, Shea, Joan-Emma, McCoy, Anne, Zanni, Martin, Hartland, Gregory, Scholes, Gregory, Loo, Joseph A, Milne, James, Tegen, Sarah B, Kulp, Daniel T, and Laskin, Julia

Subjects
Chemical Sciences
Published
2020

4. Update to Our Reader, Reviewer, and Author CommunitiesApril 2020

Author

Burrows, Cynthia J, Wang, Shu, Kim, Hyun Jae, Meyer, Gerald J, Schanze, Kirk, Lee, T Randall, Lutkenhaus, Jodie L, Kaplan, David, Jones, Christopher, Bertozzi, Carolyn, Kiessling, Laura, Mulcahy, Mary Beth, Lindsley, Craig W, Finn, MG, Blum, Joel D, Kamat, Prashant, Aldrich, Courtney C, Rowan, Stuart, Liu, Bin, Liotta, Dennis, Weiss, Paul S, Zhang, Deqing, Ganesh, Krishna N, Sexton, Patrick, Atwater, Harry A, Gooding, J Justin, Allen, David T, Voigt, Christopher A, Sweedler, Jonathan, Schepartz, Alanna, Rotello, Vincent, Lecommandoux, Sébastien, Sturla, Shana J, Hammes-Schiffer, Sharon, Buriak, Jillian, Steed, Jonathan W, Wu, Hongwei, Zimmerman, Julie, Brooks, Bryan, Savage, Phillip, Tolman, William, Hofmann, Thomas F, Brennecke, Joan F, Holme, Thomas A, Merz, Kenneth M, Scuseria, Gustavo, Jorgensen, William, Georg, Gunda I, Wang, Shaomeng, Proteau, Philip, Yates, John R, Stang, Peter, Walker, Gilbert C, Hillmyer, Marc, Taylor, Lynne S, Odom, Teri W, Carreira, Erick, Rossen, Kai, Chirik, Paul, Miller, Scott J, McCoy, Anne, Shea, Joan-Emma, Zanni, Martin, Murphy, Catherine, Scholes, Gregory, and Loo, Joseph A

Subjects
Chemical Sciences
Published
2020

5. Update to Our Reader, Reviewer, and Author Communities-April 2020.

Author

Burrows, Cynthia J, Wang, Shu, Kim, Hyun Jae, Meyer, Gerald J, Schanze, Kirk, Lee, T Randall, Lutkenhaus, Jodie L, Kaplan, David, Jones, Christopher, Bertozzi, Carolyn, Kiessling, Laura, Mulcahy, Mary Beth, Lindsley, Craig W, Finn, MG, Blum, Joel D, Kamat, Prashant, Aldrich, Courtney C, Rowan, Stuart, Bin Liu, Liotta, Dennis, Weiss, Paul S, Zhang, Deqing, Ganesh, Krishna N, Sexton, Patrick, Atwater, Harry A, Gooding, J Justin, Allen, David T, Voigt, Christopher A, Sweedler, Jonathan, Schepartz, Alanna, Rotello, Vincent, Lecommandoux, Sébastien, Sturla, Shana J, Hammes-Schiffer, Sharon, Buriak, Jillian, Steed, Jonathan W, Wu, Hongwei, Zimmerman, Julie, Brooks, Bryan, Savage, Phillip, Tolman, William, Hofmann, Thomas F, Brennecke, Joan F, Holme, Thomas A, Merz, Kenneth M, Scuseria, Gustavo, Jorgensen, William, Georg, Gunda I, Wang, Shaomeng, Proteau, Philip, Yates, John R, Stang, Peter, Walker, Gilbert C, Hillmyer, Marc, Taylor, Lynne S, Odom, Teri W, Carreira, Erick, Rossen, Kai, Chirik, Paul, Miller, Scott J, McCoy, Anne, Shea, Joan-Emma, Zanni, Martin, Murphy, Catherine, Scholes, Gregory, and Loo, Joseph A

Subjects
Chemical Sciences, General Chemistry
Published
2020

7. Supramolecular gels: a versatile crystallization toolbox.

Author

Contreras-Montoya, Rafael, Álvarez de Cienfuegos, Luis, Gavira, José A., and Steed, Jonathan W.

Subjects
MOLECULAR self-assembly, DRUG delivery systems, SINGLE crystals, MOLECULAR weights, POLYMORPHISM (Crystallography)
Abstract

Supramolecular gels are unique materials formed through the self-assembly of molecular building blocks, typically low molecular weight gelators (LMWGs), driven by non-covalent interactions. The process of crystallization within supramolecular gels has broadened the scope of the traditional gel-phase crystallization technique offering the possibility of obtaining crystals of higher quality and size. The broad structural diversity of LMWGs allows crystallization in multiple organic and aqueous solvents, favouring screening and optimization processes and the possibility to search for novel polymorphic forms. These supramolecular gels have been used for the crystallization of inorganic, small organic compounds of pharmaceutical interest, and proteins. Results have shown that these gels are not only able to produce crystals of high quality but also to influence polymorphism and physicochemical properties of the crystals, giving rise to crystals with potential new bio- and technological applications. Thus, understanding the principles of crystallization in supramolecular gels is essential for tailoring their properties and applications, ranging from drug delivery systems to composite crystals with tunable stability properties. In this review, we summarize the use of LMWG-based supramolecular gels as media to grow single crystals of a broad range of compounds. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Unprecedented light induced aggregation of cationic 1,4,5,8-naphthalenediimide amphiphiles

Author

Antoneli, Rafael G., primary, Moraes, Thaisa B. F., additional, Junqueira, Helena C., additional, Sihn, Luca M., additional, Toma, Henrique E., additional, Pedras, Bruno, additional, Ferreira, Luís F. V., additional, Frath, Denis, additional, Bucher, Christophe, additional, Steed, Jonathan W., additional, Demets, Gregóire J.-F., additional, and Triboni, Eduardo R., additional

Published
2024
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22. Studies into the effects of hexa-hapto spectator ligands on the chemistry of ruthenium

Author

Steed, Jonathan W.

Subjects
546
Abstract

This thesis describes the results of investigations into the chemistry of ruthenium complexes of hexa-hapto spectator ligands. Two specific systems have been examined. Chapters 2-5 describe aspects of the chemistry of the ruthenium(IV) chloride bridged compound [{Ru(η3:η3-C10H16)Cl(μ-Cl)}2] which contains the n3:n3-bis(allyl) ligand 2,7-dimethylocta-2,6-diene-1,8-diyl, derived from the ruthenium trichloride mediated dimerisation of isoprene. In Chapters 6 and 7 the reactivity of arenes and cyclohexadienes is examined in ruthenium complexes of the polyaromatic η6-spectator [2.2]paracyclophane. Chapter 1 offers a general introduction to arene and allyl transition metal chemistry and attempts to place the results reported herein into a wider context. In Chapter 2 the reactions of the bis(allyl)ruthenium(IV) chloride bridged dimer [{Ru(η3:η3-C10H16)Cl(μ-Cl)}2] with amines and polypyridines are examined. Bridge cleaved amine adducts of formulae [Ru(η3:η3-C10H16)Cl2L] or [{Ru(η3:η3-C10H16)Cl2}2(?-L)] (L = PhNH2, o-pda, p-pda) are reported and the diastereoisomerism of the binuclear compounds examined. The mononuclear chelate compounds [Ru(η3:η3-C10H16)Cl(L- L)][Bp4] (L-L = 2,2'-diaminodiphenyl, 2,2'-bipyridyl, 1,10-phenanthroline) and [Ru(?3-?3-C10H16)(terpy)][BF4]2 are formed from treatment of the starting material with Ag[BF4] and the appropriate ligand. Chapter 3 reports a number of carboxylato compounds of ruthenium(IV). These products occur as either 1 : 1 bidentate chelates [RU(η3:η3-C10H16)CLO2CR)] (R = Me, CH2F, CH2Cl) or 1 : 2, monodentate carboxylato aqua complexes [Ru(η3:η3-C10H16)(O2CR)2(OH2)] (R = CH2CI, CH2F, CHCl2, CHF2, CCl3, CF3). The electronic properties of the carboxylato ligand are found to be crucial to the product stoichiometry. The analogous thiocarboxylato compounds [Ru(η3:η3-C10H16)]Cl(OSCR)] (R = Me, Ph, tBu) exhibit bidentate coordination and exist as two alternative geometric isomers with the sulphur located either axially or equatorially. In the case where R = Me coordination is found to proceed via a two step process involving the monodentate thioacetic acid adduct [Ru(η3:η3-C10H16)]Cl2(S(OH)CMe}]. The related nitrato compounds [Ru(η3:η3-C10H16)Cl(NO3)] and [Ru(η3:η3-C10H16)](NO3)2] are also reported. In the latter case the "semi-chelating" nitrato ligands readily become monodentate in the presence of two electron ligands to give adducts [Ru(η3:η3-C10H16)(NO3)2L] (L = CO, py). Chapter 4 reports a range of 2-pyridinol and pyridine-2-thiol compounds of ruthenium(IV) of form [Ru(η3:η3-C10H16))Cl(pyrX)] (X = O, S) and related species. These compounds all exhibit axial and equatorial geometrical isomerism and a method based on 1H NMR spectroscopy is described for distinguishing between the two forms. In Chapter 5 a range of bi- and trinuclear compounds of ruthenium(IV) are described and their inherent diastereoisomerism studied. The bridge-cleaved adducts [{Ru(η3:n3-C10H16)Cl2}2(μ-pyz)] and [{Ru(η3:η3-C10H16)Cl2}n(μ-tra)] (n = 1, 2, 3) are reported along with the thiocyanato, carboxylato and nicotinato bridged compounds [{Ru(η3:η3-C10H16)C1(μ-SCN)}2], [{Ru(η3:η3-C10H16)Cl}2(μ-O4R)] (R = C2, C3,H2) and [RU2(η3:η3-C10H16)2CL3(μ-NC5H4CO2)]. In Chapter 6 the single nucleophilic addition reactions of simple anions N- (N = H, CN, OMe, Me) to unsymmetrical bis(arene)ruthenium(II) compounds [Ru(η6-arene)(η6-[2.2]paracyclophane)]2+ (arene = C6H6, p-MeC6H4CHMe2, l,4-(CHMe2)2C6H4, C6Me6, C16H16) are examined. It is found that the cyclophane acts as a non-innocent spectator ligand, directing nucleophiles onto other arenes coordinated to the same metal centre to give the cyclohexadienyl compounds [Ru(η6-[2.2]paracyclophane)(η5-C6R6N)]+. Chapter 7 describes the extension of the work reported in Chapter 6 to double nucleophilic addition reactions to give ruthenium(0) compounds of general form [Ru(η6-[2.2]paracyclophane)(η4-diene)]. The reactivity of these Ru(0) species towards H[BF4] is examined resulting in a range of novel agostic compounds. Mechanistic aspects are investigated by a range of deuteriation studies. Finally, Chapter 8 offers some conclusions on what has been learned about the effects the two spectator ligands studied have on the chemistry of ruthenium.

Published
1993

39. Highly Thermally Resistant Bisamide Gelators as Pharmaceutical Crystallization Media.

Author

Torres-Moya, Iván, Sánchez, Abelardo, Saikia, Basanta, Yufit, Dmitry S., Prieto, Pilar, Carrillo, José Ramón, and Steed, Jonathan W.

Subjects
THERMORESPONSIVE polymers, AMIDE derivatives, CRYSTALLIZATION, HYDROGEN bonding, METHOXY group
Abstract

Three simple bisamide derivatives (G1, G2 and G3) with different structural modifications were synthesized with easy synthetic procedures in order to test their gel behaviour. The outcomes showed that hydrogen bonding was essential in gel formation; for this reason, only G1 provided satisfactory gels. The presence of methoxy groups in G2 and the alkyl chains in G3 hindered the hydrogen bonding between N-H and C=O that occurred G1. In addition, G1 provided thermally and mechanical stable gels, as confirmed with Tsol and rheology experiments. The gels of G1 were also responsive under pH stimuli and were employed as a vehicle for drug crystallization, causing a change in polymorphism in the presence of flufenamic acid and therefore providing the most thermodynamically stable form III compared with metastable form IV obtained from solution crystallization. [ABSTRACT FROM AUTHOR]

Published
2023
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41. Derisking the Polymorph Landscape: The Complex Polymorphism of Mexiletine Hydrochloride

Author

Andrews, Jessica L., primary, Nilsson Lill, Sten O., additional, Freitag-Pohl, Stefanie, additional, Apperley, David C., additional, Yufit, Dmitry S., additional, Batsanov, Andrei S., additional, Mulvee, Matthew T., additional, Edkins, Katharina, additional, McCabe, James F., additional, Berry, David J., additional, Probert, Michael R., additional, and Steed, Jonathan W., additional

Published
2021
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46. Predictive identification of co-formers in co-amorphous systems

Author

Chambers, Luke I., Grohganz, Holger, Palmelund, Henrik, Lobmann, Korbinian, Rades, Thomas, Musa, Osama M., Steed, Jonathan W., Chambers, Luke I., Grohganz, Holger, Palmelund, Henrik, Lobmann, Korbinian, Rades, Thomas, Musa, Osama M., and Steed, Jonathan W.

Abstract

This work aims to understand the properties of co-formers that form co-amorphous pharmaceutical materials and to predict co-amorphous system formation. A partial least square - discriminant analysis (PLS-DA) was performed using known co-amorphous systems described by 36 variables based on the properties of the co-former and the binding energy of the system. The PLS-DA investigated the propensity to form co-amorphous material of the active pharmaceutical ingredients: mebendazole, carvedilol, indomethacin, simvastatin, carbamazepine and furosemide in combination with 20 amino acid co-formers. The variables that were found to favour the propensity to form co-amorphous systems appear to be a relatively large value for average molecular weight and the sum of the difference between hydrogen bond donors and hydrogen bond acceptors for both components, and a relatively small or negative value for excess enthalpy of mixing, excess enthalpy of hydrogen bonding and the difference in the Hansen parameter for hydrogen bonding of the coformer and the active pharmaceutical ingredient (API). To test the predictive power of this model, 29 potential co-formers were used to form either co-amorphous or crystalline two-component materials with mebendazole. Of these 29 two-component systems, the co-amorphous nature of a total of 26 materials was correctly predicted by the model, giving a predictive hit rate of 90 %.

Published
2021

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