Polymorphs from supramolecular gels: four crystal forms of the same silver(i) supergelator crystallized directly from its gels

Braga, Dario; D’Agostino, Simone; D’Amen, Eros; Grepioni, Fabrizia

doi:10.1039/c1cc10305a

Cited by 72 publications

(42 citation statements)

References 15 publications

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“…Another key question is why some molecules form gels, but structurally similar molecules do not, for example why Fmoc-phenylalanine-glycine forms a gel phase whilst Fmocglycine-phenylalanine does not. [18][19][20][21][22][23] Since the molecules were at one point in a fibre phase, it can be hypothesized that the packing in the resulting crystals might at the very least be related to the packing in the fibrous gel phase. In many cases, this is done by determining the structure of crystals grown from solvents where no gel is formed.…”

Section: Introductionmentioning

confidence: 99%

Hydrogels formed from Fmoc amino acids

et al. 2015

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A number of Fmoc amino acids can be effective low molecular weight hydrogelators. The type of gel formed depends on the amino acid used and, in the case of FmocF, the final pH of the system. The single crystal structure of two of the gelators (FmocF and FmocY) have been determined and the data compared to the fibre X-ray diffraction data. FmocF, which forms metastable gels, crystallises easily and the data for the fibre phase and crystal phase are relatively similar. For FmocF, the fibre axis in b is consistent with the hydrogen bonding repeat distances and the diffraction pattern calculated from the single crystal structure is a good match with the experimental fibre X-ray diffraction data. On the other hand, there are significant differences between the crystalline phase determined and the fibre phase for FmocY. The packing of FmocY within the crystal structure is created by interactions between the planar Fmoc groups, whilst it is clear that hydrogen bonding drives the self-assembly into fibrillar structures within the gels. This shows that understanding the packing in gel phase by analogy to isolated crystal structures has the potential to lead to erroneous conclusions. CrystEngCommThis journal is

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Section: Introductionmentioning

confidence: 99%

Hydrogels formed from Fmoc amino acids

et al. 2015

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“…39,94,[98][99][100] This change in phase may involve a salting-out process, 101,102 rearrangement of hydrogen bonds 94,98,103 or recombination of labile metal-ligand interactions. 104,105 The relative stabilities of products are often highly sensitive to the environment of the gelator, and in particular the solvent, which in some multicomponent systems might be temperature-dependent.…”

Section: Switchable Gelationmentioning

confidence: 99%

“…Due to their large surface areas, fibrous gels can serve as supports for catalytic particles, enzymes or quantum dots, or as tuneable media for controlling crystallisation and nanofabrication processes. 39,[118][119][120][121][122][123][124] Precipitation in a gel may deliver materials with unusual crystal structures or particle Fig. 6 Structure of L-proline-based gelator 5 and reaction schemes illustrating the dominant reaction pathways in its gels and sols.…”

Section: Switchable Gelationmentioning

confidence: 99%

Gels with sense: supramolecular materials that respond to heat, light and sound

2016

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. (2016) 'Gels with sense : supramolecular materials that respond to heat, light and sound.', Chemical society reviews., 45 (23). pp. 6546-6596. Further information on publisher's website:https://doi.org/10.1039/C6CS00435KPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Advances in the field of supramolecular chemistry have made it possible, in many situations, to reliably engineer soft materials to address a specific technological problem. Particularly exciting are "smart" gels that undergo reversible physical changes on exposure to remote, non-invasive environmental stimuli. This review explores the development of gels which are transformed by heat, light and ultrasound, as well as other mechanical inputs, applied voltages and magnetic fields. Focusing on small-molecule gelators, but with reference to organic polymers and metal-organic systems, we examine how the structures of gelator assemblies influence the physical and chemical mechanisms leading to thermo-, photo-and mechano-switchable behaviour. In addition, we evaluate how the unique and versatile properties of smart materials may be exploited in a wide range of applications, including catalysis, crystal growth, ion sensing, drug delivery, data storage and biomaterial replacement.

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“…This value corresponds to 1.28 wt %, which is striking given the high molecular weight of 1 compared to other LMWGs. [22] Other POM hybrids have also been shown to act as gelators, [21] but none formed hydrogels.Given the fact that pure 2 does not form hydrogels even at 0.3 m (50 times the CGC of 1 at pH 1.2) at neutral pH, one could assume that synergistic supramolecular interactions between the organic and inorganic moieties of 1 are responsible for gel formation.…”

Section: Angewandte Chemiementioning

confidence: 99%

Spontaneous Assembly of an Organic–Inorganic Nucleic Acid Z‐DNA Double‐Helix Structure

et al. 2016

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Herein, we report a hybrid polyoxometalate organic–inorganic compound, Na2[(HGMP)2Mo5O15]⋅7 H2O (1; where GMP=guanosine monophosphate), which spontaneously assembles into a structure with dimensions that are strikingly similar to those of the naturally occurring left‐handed Z‐form of DNA. The helical parameters in the crystal structure of the new compound, such as rise per turn and helical twist per dimer, are nearly identical to this DNA conformation, allowing a close comparison of the two structures. Solution circular dichroism studies show that compound 1 also forms extended secondary structures in solution. Gel electrophoresis studies demonstrate the formation of non‐covalent adducts with natural plasmids. Thus we show a route by which simple hybrid inorganic–organic monomers, such as compound 1, can spontaneously assemble into a double helix without the need for a covalently connected linear sequence of nucleic acid base pairs.

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Polymorphs from supramolecular gels: four crystal forms of the same silver(i) supergelator crystallized directly from its gels

Cited by 72 publications

References 15 publications

Hydrogels formed from Fmoc amino acids

Hydrogels formed from Fmoc amino acids

Gels with sense: supramolecular materials that respond to heat, light and sound

Spontaneous Assembly of an Organic–Inorganic Nucleic Acid Z‐DNA Double‐Helix Structure

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