The unusual self-organising behaviour of a glycosteroidal bolaphile

Rachedi, Fahima; Chambert, Stéphane; Ferkous, Fouad; Queneau, Yves; Cowling, Stephen J.; Goodby, John W.

doi:10.1039/b908235b

Cited by 14 publications

(5 citation statements)

References 6 publications

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“…However, on cooling, a lamellar phase is observed, which persists to temperatures below the melting point, whereupon a glass is formed. [79] Clearly, the phase behaviour is not purely thermodynamic because the same phases should be seen on cooling as well as heating. It was proposed that once in the isotropic liquid the large molecules had time to reorganise, and on cooling a different organisation was obtained than that seen on the first heating.…”

Section: Liquid Crystals 613mentioning

confidence: 99%

What makes a liquid crystal? The effect of free volume on soft matter

et al. 2015

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In this article, we probe the formation of liquid crystal and soft crystal phases as a consequence of minimising the free volume of the system either through design engineering of molecular shape or through deformation of molecular architecture. Following this concept, a number of realisations were made, for example, smectic A phases with variable layer spacing, smectic C phases without layer shrinkage, lattices of free space and fibres in N TB phases.Prologue: At the start of my thesis research in 1974, the knowledge of the structures of smectic liquid crystals was somewhat limited. Even though his thought predated the discovery of ferreoelectric behaviour in liquid crystals, George Gray had the idea that smectic C (SmC) liquid crystals might underpin potential new display applications. As I launched into synthesising new SmC variants, I started to think about why molecules should tilt over in their layers, and then onwards to question why do certain materials exhibit different forms of smectic B (SmB) phases, which was before their classification as hexatic and crystal B phases, etc. In those days I became very much interested in how the molecules pack together in condensed phases. With protractors, compasses and graph paper, the Cartesian coordinates of the atoms of a variety of molecular structures in their all trans forms were located, and their mass axes were determined for their structures by computer methods using ticker-tape which used to shoot out of the machine in volumes to yield just one result -the minimum moment of inertia. Flipping the structures about their inertia axes by 180°yielded the surface contours and the rotational volumes of the molecules. Packing them together in ways to minimise the free volume gave snapshot pictures of the local structures of various mesophases.[1] Over the passing years, I discarded this methodology for the following reasons: (1) the molecules in liquid crystal phases are rotationally disordered and are in dynamic fluctuation as demonstrated by neutron scattering studies [2,3]; (2) X-ray data showed that the molecules pack close enough together that they interpenetrate each other's independent rotational volumes, meaning they share each other's space [4,5]; (3) there were no ways to simulate the interpenetration of space, and what was free space and what was not; (4) there were only a few families of materials that could provide full data sets on structure versus phase formation; to this day there are still relatively few full homologous series of materials being reported; and lastly (5) there was no discussion of how to determine the energy cost of not fully packing space with molecules in order to minimise the remaining free volume. However, with the advent of research exploring liquid crystal materials of unconventional structure and new modelling methods such as density functional theory (DFT) simulations becoming available, our work again began to explore the steric packing arrangements of the molecules in condensed phases. [6][7][8][9][10] Then recently, one o...

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Section: Liquid Crystals 613mentioning

confidence: 99%

What makes a liquid crystal? The effect of free volume on soft matter

et al. 2015

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“…All these systems are very inspiring for designing novel carbohydrate-steroid hybrids. As a complement to earlier work which focused on dicatenar systems [25][26][27], the report below shows that the strategy can also access monocatenar systems, with glucose, galactose and cellobiose as variations on the carbohydrate side, and cholesterol and cholestenol (dihydrocholesterol), on the steroid side. The approach exploits carboxymethyl-glycoside lactones (CMGLs) which are bicyclic lactones able to readily deliver a carbohydrate onto any kind of system, by a simple addition reaction with amines forming the corresponding amides [12][13][14].…”

Section: Introductionmentioning

confidence: 72%

Synthesis and Structural Characterisation of Some Carbohydrate Steroid Hybrids

et al. 2023

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Glycosteroids are a wide family of natural and synthetic compounds with interesting and diverse architectures. Among synthetic types, we report the synthesis of some monocatenar carbohydrate steroid hybrids connected by a spacer. The strategy is based on the use of the carboxymethylglycosyl lactone strategy towards allyl amides and their connection to an allylated steroid using a cross-metathesis reaction. The scope of the reaction included glucose, galactose and cellobiose, on the carbohydrate side, and to dihydrocholesterol on the steroid side. A series of variously protected new monocatenar synthetic glycosteroids are described.

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“…The synthetic sequence based on (i) lactone opening with allylamine, (ii) cross metathesis (with a steroid derivative) and (iii) OH-2 functionalization was demonstrated to lead in a very straightforward route to the derivative (14), which showed a peculiar, hysteretic behavior upon heating or cooling, a rare observation for glycolipids [14].…”

Section: The Access To 12-bisfunctionalized Derivativesmentioning

confidence: 98%

Carboxymethyl glycoside lactone (CMGL) synthons: Scope of the method and preliminary results on step growth polymerization of α-azide-ω-alkyne glycomonomers

et al. 2010

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Carboxymethyl glycoside lactones (CMGLs) are bicyclic synthons which open readily for accessing new types of pseudo-glycoconjugates, such as sugar-amino acid hybrids, neoglycolipids, pseudodisaccharides, and membrane imaging systems. After lactone opening, free OH-2 is available for further functionalization, leading to 1,2-bisfunctionalized derivatives. This strategy is illustrated herein with new polymerizable systems of the AB type bearing both azide and alkyne functions prepared from  or  gluco-CMGL synthons. After the reaction of lactones with propargylamine, an azido group was introduced by two different sequences leading to either the 2-manno-azido or the 6-gluco-azido products. The capability of these AB monomers to undergo step growth polymerization through copper(I) catalyzed alkyne-azide cycloaddition (CuAAC) and generate glycopolytriazoles was evidenced.

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The unusual self-organising behaviour of a glycosteroidal bolaphile

Cited by 14 publications

References 6 publications

What makes a liquid crystal? The effect of free volume on soft matter

What makes a liquid crystal? The effect of free volume on soft matter

Synthesis and Structural Characterisation of Some Carbohydrate Steroid Hybrids

Carboxymethyl glycoside lactone (CMGL) synthons: Scope of the method and preliminary results on step growth polymerization of α-azide-ω-alkyne glycomonomers

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