A statistical reassessment of the evidence for the racemic distribution of quartz enantiomorphs

Támara, María; Preston, Martin

doi:10.2138/am.2009.3089

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Chiral mineral surfaces have been previously found to enhance the presence of certain amino acid enantiomers in an aqueous setting, − with computational studies on quartz or calcite carried out in support of this hypothesis. − In a vacuum environment such as the ISM, laboratory experiments have demonstrated that high-index metals with chiral surfaces can be enantioselective for a variety of chiral organic species, including propylene oxide, various amino acids, tartaric acid, and glycidol. − However, no initial symmetry-breaking event for chiral minerals has been identified on Earth, where there is an equal abundance of both enantiomorphs of chiral surfaces …”

Section: Introductionmentioning

confidence: 99%

“…52−56 However, no initial symmetry-breaking event for chiral minerals has been identified on Earth, where there is an equal abundance of both enantiomorphs of chiral surfaces. 57 The presence of clinoenstatite in the Solar System and ISM, along with the detection of enantiomeric asymmetries in carbonaceous meteorite organics, allows for the re-examination of chiral surfaces as an explanation for biomolecular homochirality. Asymmetry in chiral mineral surfaces can disrupt the symmetry of chiral organic molecules, where a surface may act as a template for the preferential enhancement of one enantiomer over another during adsorption/desorption events.…”

Section: Introductionmentioning

confidence: 99%

“… 52 − 56 However, no initial symmetry-breaking event for chiral minerals has been identified on Earth, where there is an equal abundance of both enantiomorphs of chiral surfaces. 57 …”

Section: Introductionmentioning

confidence: 99%

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Search for Chirality in Hydrogenated Magnesium Nanosilicates: A DFT and TD-DFT Investigation

Stelmach,

Dukes,

Garrod

2024

J. Phys. Chem. A

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The formation of silicate grains in the interstellar medium (ISM), especially those containing chiral surfaces such as clinopyroxenes, is poorly understood. Moreover, silicate interactions with various forms of hydrogen−proton (H + ), neutral H (HI), and molecular hydrogen (H 2 ) are of high importance as hydrogen comprises >90% of the ISM gas budget, and these species play important roles in the formation of new molecules in space. Furthermore, silicate surfaces catalyze the formation of H 2 in the interstellar medium formed on dust grain surfaces by H−H association. The technical difficulty of in situ laboratory investigations of nanosilicate nucleation using astrophysically relevant environmental conditions makes computational chemistry a useful tool for studying potential nanosilicate structures. Furthermore, chiral surfaces interacting with chiral organic molecules could serve as templates that lead to the enantiomeric excess of L-amino acids and D-polyols detected in carbonaceous meteorites. However, in order for this effect to take place, an excess of one chiral form of a mineral is required to break the symmetry. This symmetry-breaking event could have been due to the asymmetric absorption of circularly polarized light by the nanosilicate as it traverses star-forming regions. We investigate this possibility using a metastable chiral form of an enstatite dimer as an input for density functional theory (DFT) and time-dependent (TD)-DFT calculations to obtain various properties and circular dichroism spectra. All in all, twenty-six magnesium nanosilicate structures were studied using varying degrees of hydrogenation: none, with HI, with H + , and with H 2 . The HSE06/aug-cc-pVQZ level of theory was used for the DFT calculations. TD-DFT calculations utilized the CAM-B3LYP/cc-pVQZ and ωB97X-D3/cc-pVQZ functional and basic set pairings. Results show that (1) all twenty-six structures have absorption bands that fall within the 0.6−28.3 μm range available with the newly launched James Webb Space Telescope and (2) there is a small enantioselective effect by UV-CPL on the eight chiral enstatite dimers (predicted g-values of up to 0.007). While the observed effect is small, it opens up the possibility that it is the inorganic material that becomes enantiomerically biased by UV-CPL, driving chiral enhancements in meteoric organic molecules.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Search for Chirality in Hydrogenated Magnesium Nanosilicates: A DFT and TD-DFT Investigation

Stelmach,

Dukes,

Garrod

2024

J. Phys. Chem. A

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Galactic distribution of chirality sources of organic molecules

Helman

2018

Acta Astronautica

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Conceptualizing planetary habitability depends on understanding how living organisms originated and what features of environments are essential to foster abiogenesis. Estimates of the abundance of life's building blocks are confounded by incomplete knowledge of the role of chirality and racemization in organic compounds in the origination of living organisms. Chirality is an essential feature of enzymes as well as many lock-and-key type structures. There are four known processes that can act on complex organic molecules to promote racemization for abiogenesis: quantum-tunneling effects; selection via interaction with circularly polarized light (CPL); templating processes; and interactions with electrical and magnetic (EM) fields. These occur in different places, respectively: cold interstellar space; regions of space with energetic photons, dust and/or magnetic fields; and mineral surfaces (for both templating and EM fields). Chirality as a feature of terrestrial life suggests neither a special place for local development of homochirality nor for extra-terrestrial enrichment and delivery. The presence of these molecules in three competing scenarios for life's origin-chemical gardens, geothermal fields, and ice substrates-relies on a framework of hypothesis and estimation. An easily-modified worksheet is included in the supplemental material that allows a user to generate different scenarios and data related to the distribution of chiral organic molecules as building blocks for living organisms within the galaxy. A simple hypothetical mechanism for planetary magnetic field reversals, based on a high-density plasma inner core, is also presented as a means to aid in estimating field polarity and hence the orientation of racemization processes based on planetary magnetic fields.

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Isomers/enantiomers of perfluorocarboxylic acids: Method development and detection in environmental samples

et al. 2016

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A statistical reassessment of the evidence for the racemic distribution of quartz enantiomorphs

Cited by 4 publications

References 11 publications

Search for Chirality in Hydrogenated Magnesium Nanosilicates: A DFT and TD-DFT Investigation

Search for Chirality in Hydrogenated Magnesium Nanosilicates: A DFT and TD-DFT Investigation

Galactic distribution of chirality sources of organic molecules

Isomers/enantiomers of perfluorocarboxylic acids: Method development and detection in environmental samples

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