Experimental evidence of chiral symmetry breaking in crystallization from primary nucleation

Viedma, Cristóbal

doi:10.1016/j.jcrysgro.2003.09.031

Cited by 70 publications

(77 citation statements)

References 8 publications

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“…Crystallization kinetics were carried out in an experimental setup similar that was previously described. [21] The specific light rotation was measured with a JASCO digital polarimeter (Model P-1010 l = 586 nm AE 0.00058 accuracy) using a cylindrical quartz cell (6 mL) at room temperature. The enantiomeric excess is calculated from the crystal yield curve versus time and the optical rotation of the solutions.…”

Section: Methodsmentioning

confidence: 99%

Chiral Amplification in Crystallization under Ultrasound Radiation

Medina

Gedanken

Mastai

2011

Chemistry A European J

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The discovery of the importance of stereochemistry and the resolution of enantiomers dates back to the days of Pasteur, and since then the study of chirality has been of fundamental importance for both scientific and applicative purposes. [1,2] Resolution of enantiomers can be achieved by various processes based on physical, chemical, and biological techniques. [3] Nevertheless, all these techniques require the presence of optically-active molecules in order to achieve chiral resolution.During the last two decades there has been much progress in the field of chiral amplification and resolution of a symmetric chemical system in the absence of any asymmetric (chiral) environment. First experimental evidence for the spontaneous emergence of homochirality was reported by Havinga in 1954 [4] for a spontaneous homochiral phase that arises in the crystallization of methyl-ethyl-allyl-anilinium iodide. Later Kondepudi et al. induced total chiral discrimination by stirred crystallization of sodium chlorate and other chiral systems. [5][6][7][8] More recent examples of symmetry breaking during crystallization are reported in the work of Viedma, who showed in a series of papers [9][10][11] that asymmetric amplification can be achieved by the abrasive grinding of saturated solutions of enantiomorphous crystals (sodium chlorate) to obtain crystals with single-handedness. Recently, Vlieg and Blackmond [12][13][14][15] have shown that in the stirred crystallization of a suspension of nearly racemic amino acid, derivative crystals can result in a single chiral crystal of one of the enantiomeric pair in a chemical system in which enantiomers can racemize. Blackmond and Viedma in a joint publication [16] illustrated the evolution of total enantioenrichment of the solid phase of aspartic acid by solutionphase racemization. The authors also investigated the mechanism for this transformation, showing that the process occurs even in the absence of the attrition enhancement. [16] In this Communication, we describe the effect of ultrasound radiation on the kinetic resolution of enantiomers during crystallization. It should be mentioned that the ability of ultrasound radiation to serve as a false chiral force was first proposed by Cintas [17] and the concept of enantioselective crystallization under ultrasound was later demonstrated by Chen and co-workers [18] in the crystallization of sodium chlorate in the presence of seed crystals. In a more recent paper Cintas [19] emphasized the potential of ultrasound irradiation in enantioselective crystallization.Herein we demonstrate that the application of ultrasound radiation to the crystallization of amino acids affects crystallization kinetics, crystal morphology, and causes chiral amplification. To demonstrate the effect of ultrasounds on chiral amplification in a crystallization process, a model for chiral crystallization has to be selected. We selected dlthreonine as a model system for conglomerate crystallization. We have to point out that our experimental system has two unique propertie...

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Section: Methodsmentioning

confidence: 99%

Chiral Amplification in Crystallization under Ultrasound Radiation

Medina

Gedanken

Mastai

2011

Chemistry A European J

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“…These observations cannot be explained by the mechanism of natural convection [17], which attributes chiral crystal proliferation to the secondary nucleation companying with the hydrodynamic motion, because the achievement of high CEE requires the existence of a dominative chiral structure nuclei in homogeneous nucleation processes. Viedma [18] showed that high supersaturation causes almost complete chiral symmetry breaking. And an elegant observation in boiling solution system elaborates that there exists chiral cluster with CEE dependency of supersaturation before primary nucleation [19].…”

Section: Resultsmentioning

confidence: 99%

Chiral Symmetry Breaking Induced by Temperature Fluctuation in an Open System to Mimic Chirality Evolution in Nature

Pan¹,

Xu²,

Sun³

et al. 2015

Advances in Intelligent Systems Research

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Abstract. The chiral symmetry breaking during the nucleation and growth of sodium chlorate and sodium bromate from their aqueous solutions was investigated under natural unstirred conditions. The results suggested that temperature fluctuation inherently existing in nature is a possible main driving force causing fluctuating supersaturation conditions, under which the chiral symmetry breaking is induced. Density gradient in the solution associated with water evaporation and solute concentration variation causes natural convection, which was found to amplify the existed biased handed structure to yield high value of the absolute crystal enantiomeric excess (CEE) in the absence of external stirring. Experimental results also showed that the chiral symmetry breaking process induced by temperature fluctuation is not significantly affected by the presence of achiral solid particles.

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“…8 Moreover, if there is discrimination in the solid state, recent experiments suggest that the ultimate state of the system is homochirality, that is, a spontaneous break of symmetry. [9][10][11][12] Since Pasteur's pioneer work, several generations of researchers, representing more than 150 years of experience, have shown the very strong trend towards the formation of stoichiometric o1-14 compounds (co-crystals). Even if significant deviations appear in some series of molecules (e.g.…”

Section: Example 3: a Hybrid Salt-co-crystalmentioning

confidence: 99%

Limits of the Co-crystal Concept and Beyond

Coquerel

2011

Pharmaceutical Salts and Co-Crystals

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In this chapter, views of co-crystals are broadened. Indeed, any classification has its limits and, clearly, the thermodynamics of heterogeneous equilibria can help to replace the concept of the co-crystal in a more general perspective. Co-crystals are nothing other than intermediate compounds. Nevertheless, the concept suffers from intrinsic uncertainties due to the numerous situations in which they can occur such as the continuum between solvate and co-crystals, hybrid salt-co-crystals, multi-epitaxy and so on. It is even possible to find the same partners with simultaneously salt-like and co-crystal-like relationships in a given crystal structure. Therefore, rather than creating questionable terms and maintaining endless semantic debates with poor added value, the scientific community should concentrate more on the three long lasting problems related to intermediate compounds listed below: 1. Prediction of intermediate compounds: indeed, apart from statistical trends (e.g. racemic compounds as detailed in this chapter), there is no way to predict the existence of an intermediate compound with acceptable reliability. 2. Prediction of the attributes of these intermediate compounds: to date the connection between structures and properties is very weak despite the evident interest. 3. How to design a process to obtain those intermediate phases with a good yield and minimum side products? Moreover these processes should fulfil the specifications for the final products such as crystallinity, crystal size distribution, morphology, and so on. These questions are really meaningful from an industrial perspective and for advancing knowledge in the organic solid state.

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Experimental evidence of chiral symmetry breaking in crystallization from primary nucleation

Cited by 70 publications

References 8 publications

Chiral Amplification in Crystallization under Ultrasound Radiation

Chiral Amplification in Crystallization under Ultrasound Radiation

Chiral Symmetry Breaking Induced by Temperature Fluctuation in an Open System to Mimic Chirality Evolution in Nature

Limits of the Co-crystal Concept and Beyond

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