Sol-gel phase transition of brucine-appended porphyrin gelator: a study by vibrational circular dichroism spectroscopy

Setnička, Vladimı́r; Urbanová, Marie; Pataridis, Statis; Král, Vladimı́r; Volka, K.

doi:10.1016/s0957-4166(02)00740-1

Cited by 26 publications

(18 citation statements)

References 27 publications

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“…The positive couplet (bisignate VCD pattern, positive to lower and negative to higher energy) formed by these bands is slightly distorted from an ideal shape due to the contribution from the two types of carbonyl groups, that is, of the hydrazide and the guanine moieties (see diagram in the Experimental Section). These carbonyls give also two pronounced partly overlapping IR bands at 1676 and 1657 cm Taken together, the strong magnification in VCD intensity observed for the hydrogel at 38 mmol L À1 (Figure 1) is due to a coupling of C=O modes between particular molecules during the gelation process and may be attributed, according to similarity with published data, [44][45][46] to the formation of highly ordered supramolecular assemblies. Transmission electron microscopy revealed the presence of long fibers forming the gel.…”

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confidence: 82%

“…Some of us have been developing VCD not only to study noncovalent interactions of biologically interesting molecules, [38][39][40][41][42][43] but also to extend its applicability to the field of supramolecular chemistry. [44][45][46] Experimental Section Materials: Guanosine-5'-hydrazide (G-1) was synthesized and characterized as described previously. [29] Deuterium oxide (D 2 …”

Section: Introductionmentioning

confidence: 99%

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Investigation of Guanosine‐Quartet Assemblies by Vibrational and Electronic Circular Dichroism Spectroscopy, a Novel Approach for Studying Supramolecular Entities

Setnička

Urbanová

Volka

et al. 2006

Chemistry A European J

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The self-assembly of guanosine-5'-hydrazide G-1 in D(2)O, in the presence and absence of sodium cations, has been investigated by chiroptical techniques: electronic (ECD) and the newly introduced vibrational (VCD) circular dichroism spectroscopy. Using a combination of ECD and VCD with other methods such as IR, electron microscopy, and electrospray ionization mass spectrometry (ESI-MS) it was found that G-1 produces long-range chiral aggregates consisting of G-quartets, (G-1)(4), subsequently stacked into columns, [(G-1)(4)](n), induced by binding of metal cations between the (G-1)(4) species. This process, accompanied by gelation of the sample, is highly efficient in the presence of an excess of sodium cations, leading to aggregates with strong quartet-quartet interaction. Thermally induced conformational changes and conformational stability of guanosine-5'-hydrazide assemblies were studied by chiroptical techniques and the melting temperature of the hydrogels formed was obtained. The temperature-dependent experiments indicate that the long-range supramolecular aggregates are dissociated by increasing temperature into less ordered species, monomers, or other intermediates in equilibrium, as indicated by MS experiments.

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confidence: 82%

Section: Introductionmentioning

confidence: 99%

Investigation of Guanosine‐Quartet Assemblies by Vibrational and Electronic Circular Dichroism Spectroscopy, a Novel Approach for Studying Supramolecular Entities

Setnička

Urbanová

Volka

et al. 2006

Chemistry A European J

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“…22,23 Furthermore, Setnička et al have shown that it was possible to study the sol-gel phase transition, at 10 21 to 10 22 M concentration, by VCD spectroscopy. 24 This concentration regime is already considerably low for VCD spectroscopy, due to its low sensitivity compared with CD spectroscopy, where concentrations can be used as low as 10 26 M. Here we show that is possible to extend the use of VCD spectroscopy to supramolecular polymeric systems in relatively dilute solutions, i.e., as low as 1.8 3 10…”

Section: Introductionmentioning

confidence: 73%

C₃‐symmetrical self‐assembled structures investigated by vibrational circular dichroism

et al. 2008

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We demonstrate by using vibrational circular dichroism (VCD) spectroscopy that it is possible to investigate the chirality of a supramolecular polymeric system in relatively dilute solutions. Chiral C 3 -symmetrical discotic molecules, based on a trialkylbenzene-1,3,5-carboxamide, form supramolecular columnar stacks with a righthanded helical structure in solution due to intermolecular hydrogen bonds. The handedness of the supramolecular chirality is determined using electronic spectroscopy measurements. Under dilute conditions (at 10 23 M concentrations), it was also possible to probe the hydrogen bonding moieties with IR and VCD spectroscopy on these selfassembled structures. In combination with density functional theory (DFT) calculations, we could verify the preference for a right-handed chirality in the helical stacks and the nonplanar orientation of the carbonyl groups present in the molecule. This chiral arrangement is in agreement with the structure determined for a related benzene-1,3,5-tricarboxamide by X-ray diffraction. Chirality 20: 1016-1022, 2008. V

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“…Therefore VCD provide valuable information on the involvement of specific parts of molecules in the formation of chiral self-assemblies. For example, the self-assembly of brucine-porphyrin conjugates 71 and of a chiral biphenyl bicarboxylic acid 72 were followed studying the VCD in the C¼ ¼O at ca. 1655 cm 21 …”

Section: The Self-assembly Of Guanosine Derivativesmentioning

confidence: 99%

The use of circular dichroism spectroscopy for studying the chiral molecular self‐assembly: An overview

et al. 2007

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Self-assembly plays an important role in the formation of many chiral biological structures and in the preparation of chiral functional materials. Therefore the control of chirality in synthetic or biological self-assembled systems is important either for the comprehension of recognition phenomena or to obtain materials with predictable and controllable properties. Circular dichroism was developed to study molecular chirality, however, because of its outstanding sensitivity to chiral perturbations of the system under investigation; it has been extended more recently to supramolecular chemistry. In particular, self-assembly processes leading to the formation of chiral supramolecular architectures (and eventually to gels or liquid crystal phases) can be monitored by CD. Furthermore, CD spectroscopy often allows one to obtain structural information on the assembled structures. This review deals with representative contributions to the study of supramolecular chirality by means of circular dichroism.

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Sol-gel phase transition of brucine-appended porphyrin gelator: a study by vibrational circular dichroism spectroscopy

Cited by 26 publications

References 27 publications

Investigation of Guanosine‐Quartet Assemblies by Vibrational and Electronic Circular Dichroism Spectroscopy, a Novel Approach for Studying Supramolecular Entities

Investigation of Guanosine‐Quartet Assemblies by Vibrational and Electronic Circular Dichroism Spectroscopy, a Novel Approach for Studying Supramolecular Entities

C₃‐symmetrical self‐assembled structures investigated by vibrational circular dichroism

The use of circular dichroism spectroscopy for studying the chiral molecular self‐assembly: An overview

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Sol-gel phase transition of brucine-appended porphyrin gelator: a study by vibrational circular dichroism spectroscopy

Cited by 26 publications

References 27 publications

Investigation of Guanosine‐Quartet Assemblies by Vibrational and Electronic Circular Dichroism Spectroscopy, a Novel Approach for Studying Supramolecular Entities

Investigation of Guanosine‐Quartet Assemblies by Vibrational and Electronic Circular Dichroism Spectroscopy, a Novel Approach for Studying Supramolecular Entities

C3‐symmetrical self‐assembled structures investigated by vibrational circular dichroism

The use of circular dichroism spectroscopy for studying the chiral molecular self‐assembly: An overview

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C₃‐symmetrical self‐assembled structures investigated by vibrational circular dichroism