Sage Journals: Discover world-class research

Abstract

The preferential synthesis or destruction of a single enantiomer by ultraviolet circularly polarized light (UV-CPL) has been proposed as a possible triggering mechanism for the extraterrestrial origin of homochirality. Herein, we investigate the photoabsorption property of propylene oxide (c-C₃H₆O) for UV-CPL in the Lyman-α region. Our calculations show that c-C₃H₆O was produced by CH₃ ⁺ and CH₃CH(OH)CH₃ or C₃H₇ ^• and O (triplet). The computed electronic circular dichroism spectra show that c-C₃H₆O and the intermediate (CH₃CH(OH)CH₂ ⁺) could absorb the UV-CPL originating from the Lyman-α emitter spectrum, suggesting that the photolysis of c-C₃H₆O or CH₃CH(OH)CH₂ ⁺ upon irradiation could induce chiral symmetry breakage.

1. Introduction

Chiral organic molecules cannot be brought into congruence by translation, rotation, or conformational changes, while they are distinguished by two mirror images. The enantiomers of chiral molecules have two absolute configurations denoted as R and S (l and d in biomolecules). Most organisms on Earth selectively use l-form amino acids and d-form sugars for their body compositions, and this natural selection is called homochirality. The origin of homochirality has been a key mystery in the study of the origin of life on Earth and has long been a matter of controversy.

Since the discovery of the enantiomeric excess (ee) of amino acids, including that in the Murchison meteorite (Cronin and Pizzarello, 1997; Engel and Macko, 1997), the cosmic origin of homochirality has been the focus of several studies. Various enantiomer formation and amplification mechanisms have been suggested and discussed (Kondepudi et al., 1990; Bonner, 1991; Soai et al., 1995; Cronin and Pizzarello, 1997; Engel and Macko, 1997; Bailey, 2000; Kawasaki et al., 2006; Fletcher et al., 2007; Garcia et al., 2019; Glavin et al., 2020). One of these mechanisms is the preferential synthesis or destruction of a single enantiomer through exposure to ultraviolet circularly polarized light (UV-CPL). This mechanism has been proposed as a possible triggering mechanism to induce asymmetry in amino acids (Bailey et al., 1998; Garcia et al., 2019; Glavin et al., 2020) as a physical process, which is widely recognized as one of the extraterrestrial origins of homochirality. Indeed, the selective destruction of enantiomers by UV-CPL has been confirmed in laboratory experiments (Flores et al., 1977; Meierhenrich et al., 2005, 2010; Nuevo et al., 2007; Meinert et al., 2014, 2015; Tia et al., 2014). In addition, infrared CPL of up to 17% was detected within the high-mass star-forming regions of the Orion molecular cloud (OMC-1) (Bailey et al., 1998). The infrared CP image shows that the infrared CPL region was spatially extended around young stellar objects (Fukue et al., 2010; Kwon et al., 2013, 2014, 2016, 2018), which were significantly larger than the size of our solar system. Recently, high infrared circular polarization induced by scatterings from dust grains aligned in magnetic fields has been explored by radiative transfer calculations (Fukushima et al., 2020). Such experiments and measurements are consistent with the astrophysical scenario of the origin of homochirality. In particular, in the early phase of the galactic evolution, the strongest emission in the pan-galactic light is the Lyman-α (Lyα) line with an emission of 10.2 eV (121.6 nm). This emission is caused by relaxation from the first electronic excited state to the ground state of a hydrogen atom. Such galaxies emitting Lyα radiation are observed as Lyman-α emitters (LAEs) (Shibuya et al., 2014). Therefore, the consideration of the photolysis of chiral molecules by Lyα irradiation can provide insights into a possible triggering mechanism to induce asymmetry in amino acids.

McGuire et al. (2016) detected a chiral molecule—propylene oxide (c-C₃H₆O)—for the first time in the Sagittarius B2 star-forming region using a telescope. However, the possibility of the existence of ee in the case of c-C₃H₆O could not be determined. Nevertheless, knowing the possibility of its existence is of significant importance to deeply understand the origin of homochirality. Considering the astrophysical scenario of the destruction of enantiomers through CPL irradiation, herein, we investigated the possibility of ee generation for c-C₃H₆O using quantum chemical calculations. We determined the formation pathways of c-C₃H₆O based on those of ethylene oxide (c-C₂H₄O) (Dickens et al., 1997; Turner and Apponi, 2001; Bennett et al., 2005). Furthermore, we calculated the oscillator and rotational strengths of electronic excitation for the chiral species during the formation processes to discuss the possibility of photolysis by UV-CPL absorption in the Lyα region.

2. Methods

2.1. Computational details

All calculations were performed by using the density functional theory (DFT) and post-Hartree-Fock (post-HF) methods implemented in the Gaussian 16 program package (Frisch et al., 2016). We performed full geometry optimizations using DFT calculations with the B3LYP functional and the aug-cc-pVTZ basis set, and then determined the energies using post-HF calculations with the CCSD(T) level of theory and the aug-cc-pVTZ basis set for the optimized geometries. Our previous DFT calculations confirmed that the B3LYP functional suitably reproduced the geometrical structures and total energies, which were in close agreement with the reliable CCSD(T) results (Kayanuma et al., 2017; Sato et al., 2018; Shoji et al., 2022). By calculating the analytical harmonic vibrational frequencies, we confirmed that the obtained local minima and transition states have no and one imaginary frequency mode, respectively.

Electronic excitation energies, oscillator strengths, and rotational strengths were calculated for the chiral species during the synthesis of c-C₃H₆O by using time-dependent density functional theory (TD)-DFT calculations with the CAM-B3LYP functional and the daug-cc-pVQZ basis set. We calculated 100 excited states to obtain the electronic circular dichroism (CD) spectra, in which Gaussian functions with a bandwidth of 0.1 eV for each excitation position (Rizzo and Vahtras, 2011) were used in constructing the spectra.

2.2. Selection of reaction pathways

We focused on the formation of ethylene oxide (c-C₂H₄O) to investigate the reaction pathway of c-C₃H₆O formation. In previous studies, some c-C₂H₄O formation pathways, based on the interstellar environment in hot-core and star-forming regions such as Sagittarius B2(N), have been proposed (Dickens et al., 1997; Turner and Apponi, 2001; Bennett et al., 2005). The three types of proposed formation pathways are as follows.

C {H_{3}}^{+} + C_{2} H_{5} O H \to C_{2} H_{5} O^{+} + C H_{4}

(1.1)

C_{2} H_{5} O^{+} + e^{-} \to c - C_{2} H_{4} O + H^{∙}

(1.2)

(Dickens et al., 1997),

O + C_{2} {H_{5}}^{∙} \to c - C_{2} H_{4} O + H^{∙}

(2)

(Turner and Apponi, 2001), and

C {H_{3}}^{+} + H C H O \to c - C_{2} H_{4} O + C H_{2} C H O H

(3)

(Bennett et al., 2005). No details on path 3 are available in the literature.

Based on the above pathways, the following three types of c-C₃H₆O formation pathways were investigated:

C {H_{3}}^{+} + C H_{3} C H (O H) C H_{3} \to C_{3} H_{7} O^{+} + C H_{4}

(A−1)

C_{3} H_{7} O^{+} + e^{-} \to c - C_{3} H_{6} O + H^{∙}

(A−2)

denoted as path A,

O + C_{3} {H_{7}}^{∙} \to c - C_{3} H_{6} O + H^{∙}

(B)

denoted as path B, and

C {H_{3}}^{+} + C H_{3} C H O \to C H_{3} O C H C {H_{3}}^{+}

(C−1)

C H_{3} O C H C {H_{3}}^{+} + e^{-} \to c - C_{3} H_{6} O + H^{∙}

(C−2)

denoted as path C. Path C was considered by using only the reactant species and stoichiometry of path 3 because the details have not been mentioned.

3. Results and Analysis

3.1. Reaction pathways

Path A

Path A consists of two reactions: (1) C₃H₇O⁺ and CH₄ generation from CH₃ ⁺ and CH₃CH(OH)CH₃ (A-1), and (2) the formation of c-C₃H₆O (A-2). Figure 1 shows the computed energy diagrams for path A at the CCSD(T)/aug-cc-pVTZ level of theory. Although CH₃CH(OH)CH₃ has several stable rotamers, their relative energies of a few kcal mol⁻¹ (Kahn and Bruice, 2005; Snow et al., 2011) are sufficiently low to not affect the entire computed energy diagram. Therefore, we only focused on the specific conformation that proceeds the desired reactions, in addition to Paths B and C. CH₃ ⁺ and CH₃CH(OH)CH₃ (A1) are initially transformed into CH₄ and CH₃CH(OH)CH₂ ⁺ (A2), respectively, through hydrogen abstraction. The reaction is exothermic (2.68 eV) without any reaction barriers, indicating that the reaction proceeds spontaneously when CH₃ ⁺ and CH₃CH(OH)CH₃ come into contact with each other. Through reduction (i.e., the addition of an electron (e⁻)), CH₃CH(OH)CH₂ ⁺ produces c-C₃H₆O and H (A5); the complex of CH₃CH(OH)CH₂ ⁺ and e⁻ (A3) transforms into CH₃CH(OH)CH₂ (A4) and leads to A5 via a transition state (A-TS). Because A-TS and A5 have negative energies relative to A3, c-C₃H₆O formation can occur by adding an e⁻ to CH₃CH(OH)CH₂ ⁺. This suggests that path A is a c-C₃H₆O formation pathway.

FIG. 1.

Computed energy diagrams for path A at the CCSD(T)/aug-cc-pVTZ level of theory together with the optimized structure of the transition state at the B3LYP/aug-cc-pVTZ level of theory. The values in parentheses represent the energies calculated at the B3LYP/aug-cc-pVTZ level of theory. Relative energies with respect to A1 and A3 are expressed in electron volts. The energy of A3 was calculated for the state with an electron added to the structure of CH₃CH(OH)CH₂ ⁺.

Path B

We considered path B for the formation of c-C₃H₆O and H from C₃H₇ ^• and O (triplet). Our calculations reveal that the addition of C₃H₇ ^• and O (triplet) (B1) produces CH₂OCH₂CH₃ (B2) with an energy of −3.96 eV without any reaction barriers, as shown in Fig. 2. B2 produces c-C₃H₆O and H (B3) via a transition state (B-TS). Because B-TS and B3 are calculated to have negative energies relative to B1, c-C₃H₆O formation can occur by the addition of C₃H₇ ^• and O (triplet). This indicates that path B is also a c-C₃H₆O formation pathway, similar to path A.

FIG. 2.

Computed energy diagrams for path B at the CCSD(T)/aug-cc-pVTZ level of theory together with the optimized structure of the transition state at the B3LYP/aug-cc-pVTZ level of theory. The values in parentheses represent the energies calculated at the B3LYP/aug-cc-pVTZ level of theory. Relative energies with respect to B1 are expressed in electron volts.

Path C

Finally, we considered path C, which comprises two reactions, as follows: (1) CH₃CHOCH₃ ⁺ generation from CH₃ ⁺ and CH₃CHO (C-1), and (2) the formation of c-C₃H₆O (C-2). Figure 3 shows the computed energy diagrams for path C. The addition of CH₃ ⁺ and CH₃CHO (C1) initially produces CH₃CHOCH₃ ⁺ (C2). The reaction is exothermic (-3.89 eV) without any reaction barriers, which indicates that the reaction proceeds automatically when CH₃ ⁺ and CH₃CHO come into contact with each other. CH₃CHOCH₃ ⁺ then forms CH₃CHOCH₃ ^• (C4) by the addition of an e⁻ with an energy of -0.66 eV. CH₃CHOCH₃ ^• generates CH₃CH^•OCH₂ ^• (C5) with hydrogen cleavage, and the reaction is endothermic (4.22 eV). Finally, c-C₃H₆O is produced by the C–C bond formation of CH₃CH^•OCH₂ ^• via a transition state (C-TS). Because the energies for C5 and C-TS are remarkably higher than those for C3, we do not consider path C as a formation pathway of c-C₃H₆O.

FIG. 3.

Computed energy diagrams for path C at the CCSD(T)/aug-cc-pVTZ level of theory together with the optimized structure of the transition state at the B3LYP/aug-cc-pVTZ level of theory. The values in parentheses represent the energies calculated at the B3LYP/aug-cc-pVTZ level of theory. Relative energies with respect to C1 and C3 are expressed in electron volts.

3.2. Photo-absorption property of CPL

We investigated the photo-absorption property of the chiral species for Lyα with an emission of 10.2 eV (121.6 nm) and discussed the possibility of photolysis through the absorption of CPL in the Lyα region.

In previous works, the CD spectrum of c-C₃H₆O was measured in the vacuum ultraviolet region up to 8.2 eV (151 nm) (Carnell et al., 1991) and 9.0 eV (138 nm) (Breest et al., 1994). In the spectrum, three band maxima appeared at 7.1 eV (175 nm), 7.7 eV (161 nm), and 8.4 eV (148 nm), and the CD peak sign at 7.7 eV was opposite to the other peak signs at 7.1 and 8.4 eV (Breest et al., 1994). The simulated CD spectrum was also obtained from DFT and post-HF calculations (Carnell et al., 1991; Turner and Apponi, 2001; Miyahara et al., 2009; Varsano et al., 2009; Kröner, 2015). The results were qualitatively in agreement with the experimental CD spectrum. However, even the SAC-CI calculations, which provided a good theoretical description of the first two spectral bands, overestimated the rotatory strengths for the state corresponding to the third band (Miyahara et al., 2009; Kröner, 2015). According to the benchmark studies on CD simulations using TD-DFT calculations (Turner and Apponi, 2001; Jang et al., 2018), the M06-2X, CAM-B3LYP, and ωB97X-D functionals are feasible (Jang et al., 2018). Moreover, rotatory strengths require doubly augmented basis sets of at least triple zeta quality to reach a similar degree of convergence with the CAM-B3LYP functional (Turner and Apponi, 2001). The electronic excitation energies, oscillator strengths, and rotational strengths of c-C₃H₆O and CH₃CH(OH)CH₂ ⁺ (A3 in Fig. 1), which are chiral species obtained under the c-C₃H₆O formation pathways, were calculated from the TD-DFT calculations with the CAM-B3LYP functional and daug-cc-pVQZ basis set.

Figure 4a shows the computed CD and UV spectra of (R)-c-C₃H₆O. Three main peaks between 145 and 180 nm, with one positive and two negative signs, are observed and are consistent with the experimental observations (Breest et al., 1994). Herein, we focus on the photoabsorption property of the LAE spectrum with an intense peak at 10.2 eV (121.6 nm), although we cannot compare these results with the experimental results around the higher energy region because of the lack of experimental observations in this region. The calculated UV spectrum shows that c-C₃H₆O absorbs light at approximately 120 nm because of its strong oscillator strength. The calculated CD spectrum has a slightly negative sign at 121.6 nm. Figure 4b also shows the computed CD and UV spectra of (R)-CH₃CH(OH)CH₂ ⁺. We consider the convolution of our CD spectra and the LAE spectrum (Shibuya et al., 2014), as shown in Fig. 5. In both cases, intense peaks near 121.6 nm are observed. Therefore, we suggest that both c-C₃H₆O and CH₃CH(OH)CH₂ ⁺ can absorb the Lyα line.

FIG. 4.

Simulated CD (blue line) and UV (red dashed line) spectra of (a) (R)-c-C₃H₆O and (b) (R)-CH₃CH(OH)CH₂ ⁺ using CAM-B3LYP/daug-cc-pVQZ level of theory. The spectra were obtained using Gaussian functions with a broadening parameter of 0.1 eV. The black line represents the position at 121.1 nm.

FIG. 5.

Convolution of the observational LAE spectrum and calculated CD spectra of (a) (R)-c-C₃H₆O and (b) (R)-CH₃CH(OH)CH₂ ⁺ between 120 and 140 nm.

A previous experimental study demonstrated that irradiating c-C₃H₆O in the gas phase at 185 nm generated propanal and acetone (Paulson et al., 1977). The experimental results and our computational results of the CD spectrum imply the occurrence of photolysis of c-C₃H₆O by Lyα, although the wavelength is different from that used in the previous experimental measurements. Determining the detailed photolysis reaction mechanism is a future challenge; however, the present results provide a possibility of the formation of c-C₃H₆O homochirality in space. Experimental verification is required to examine the photolysis by CPL irradiation in detail.

4. Conclusions

In this study, we investigated the formation and possible photolysis of c-C₃H₆O, a chiral molecule first detected in the Sagittarius B2 star-forming region (McGuire et al., 2016), under interstellar conditions. We focused on the previously proposed c-C₂H₄O formation mechanism (Dickens et al., 1997; Turner and Apponi, 2001; Bennett et al., 2005) to investigate the reaction pathways of c-C₃H₆O formation at the atomic level, which cannot be detected by space observation due to the short lifetime of most of the intermediates. The computed energy diagrams show two energetically downhill pathways for c-C₃H₆O formation. One pathway consisted of two reactions: (1) C₃H₇O⁺ and CH₄ generation from CH₃ ⁺ and CH₃CH(OH)CH₃, and (2) c-C₃H₆O formation from C₃H₇O⁺ and e⁻. The other pathway produced c-C₃H₆O from C₃H₇ ^• and O (triplet). Therefore, c-C₃H₆O was produced by CH₃ ⁺ and CH₃CH(OH)CH₃ or C₃H₇ ^• and O (triplet), as indicated by our quantum chemical calculations. Because the reactants, the product, and several intermediates with a long lifetime can be detected by observation, the pathway proposed by our calculations is plausible in an interstellar environment. Furthermore, the CD spectra obtained from DFT and post-HF calculations indicate that c-C₃H₆O and CH₃CH(OH)CH₂ ⁺ could absorb UV-CPL from the LAE spectrum. This suggests that the photolysis of c-C₃H₆O or CH₃CH(OH)CH₂ ⁺ under CPL irradiation could induce chiral symmetry breakage. Infrared CPL was detected within the high-mass star-forming regions of OMC-1 (Bailey et al., 1998), and the infrared CP image also shows that the infrared CPL region was spatially extended around young stellar objects (Fukue et al., 2010; Kwon et al., 2013, 2014, 2016, 2018). In addition, LAEs were observed in the early phase of the galactic evolution (Shibuya et al., 2014). These experiments and measurements, in addition to our present calculation results, are consistent with the astrophysical scenario of the origin of homochirality. To prove this scenario, further experimental verification is required to examine the photolysis by CPL irradiation in detail. The short-lived intermediates discovered in our calculations, the formation energies of various reactions, and other calculated spectroscopic data are expected to be beneficial for their experimental verification.

Footnotes

Acknowledgments

This work was supported in part by the Multidisciplinary Cooperative Research Program at the Center for Computational Sciences, University of Tsukuba. Some of the computations were performed using the computer facilities at the Research Institute for Information Technology, Kyushu University, and the Research Center for Computational Science, Okazaki, Japan (Project: 22-IMS-C122). We would like to thank Editage (www.editage.com) for English language editing.

Authorship Confirmation Statement

Y.H., H.N., and T.S. conducted the computations and analyses and interpreted the data with the help of N.W., M.K., M.S., M.U., and Y.S. Y.H. wrote the paper, and the others edited it. All the authors contributed to the final manuscript.

Authors' Disclosure Statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Funding Statement

This work was partly supported by JSPS Grants-in-Aid for Scientific Research (JP19K15524 and JP19H00697), MEXT Grants-in-Aid for Scientific Research on Innovative Areas (JP21H00014 and JP21H05419), the Cooperative Research Program of “Network Joint Research Center for Materials and Devices,” and a research grant from The Mazda Foundation.

Supplementary Material

Supplementary Table S1

Supplementary Table S2

Supplementary Table S3

Abbreviations Used

Associate Editor: Christopher McKay

References

Bailey

Chirality and the origin of life. Acta Astronaut, 2000; 46(10–12):627–631; doi: 10.1016/S0094-5765(00)00024-2.

Bailey

, Chrysostomou

, Hough

, et al. Circular polarization in star-formation regions: Implications for biomolecular homochirality. Science, 1998; 281(5377):672–674; doi: 10.1126/science.281.5377.672.

Bennett

, Osamura

, Lebar

, et al. Laboratory studies on the formation of three C₂H₄O isomers—acetaldehyde (CH₃CHO), ethylene oxide (c-C₂H₄O), and vinyl alcohol (CH₂CHOH)—in interstellar and cometary ices. Astrophys J, 2005; 634(1):698–711; doi: 10.1086/452618.

Bonner

WA.

The origin and amplification of biomolecular chirality. Orig Life Evol Biosph, 1991; 21:59–111; doi: 10.1007/BF01809580.

Breest

, Ochmann

, Pulm

, et al. Experimental circular dichroism and VUV spectra of substituted oxiranes and thiiranes. Mol Phys, 1994; 82(3):539–551; doi: 10.1080/00268979400100404.

Carnell

, Peyerimhoff

, Breest

, et al. Experimental and quantum-theoretical investigation of the circular-dichroism spectrum of R-methyloxirane. Chem Phys Lett, 1991; 180(5):477–481; doi: 10.1016/0009-2614(91)85153-N.

Cronin

, Pizzarello

Enantiomeric excesses in meteoritic amino acids. Science, 1997; 275(5302):951–955; doi: 10.1126/science.275.5302.951.

Dickens

, Irvine

, Ohishi

, et al. Detection of interstellar ethylene oxide (c-C₂H₄O). Astrophys J, 1997; 489(2):753–757; doi: 10.1086/304821.

Engel

, Macko

. Isotopic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite. Nature, 1997; 389:265–268; doi: 10.1038/38460.

10.

Fletcher

, Jagt

, Feringa

. An astrophysically relevant mechanism for amino acid enantiomer enrichment. Chem Commun, 2007; 25:2578–2580; doi: 10.1039/b702882b.

11.

Flores

, Bonner

, Massey

. Asymmetric photolysis of (RS)-leucine with circularly polarized ultraviolet light. J Am Chem Soc, 1977; 99(11):3622–3625; doi: 10.1021/ja00453a018.

12.

Frisch

, Trucks

, Schlegel

, et al. Gaussian16, Rev. A.03. Gaussian, Inc., Wallingford CT; 2016.

13.

Fukue

, Tamura

, Kandori

, et al. Extended high circular polarization in the Orion massive star forming region: Implications for the origin of homochirality in the solar system. Orig Life Evol Biosph, 2010; 40:335–346; doi: 10.1007/s11084-010-9206-1.

14.

Fukushima

, Yajima

, Umemura

High circular polarization of near-infrared light induced by micron-sized dust grains. Mon Not R Astron Soc, 2020; 496(3):2762–2767; doi: 10.1093/mnras/staa1718.

15.

Garcia

, Meinert

, Sugahara

, et al. The astrophysical formation of asymmetric molecules and the emergence of a chiral bias. Life, 2019; 9(1):29; doi: 10.3390/life9010029.

16.

Glavin

, Burton

, Elsila

, et al. The search for chiral asymmetry as a potential biosignature in our solar system. Chem Rev, 2020; 120(11):4660–4689; doi: 10.1021/acs.chemrev.9b00474.

17.

Jang

, Kim

, Heo

Benchmarking study on time-dependent density functional theory calculations of electronic circular dichroism for gas-phase molecules. Comp Theor Chem, 2018; 1125:63–68; doi: 10.1016/j.comptc.2018.01.003.

18.

Kahn

, Bruice

. Focal-point conformational analysis of ethanol, propanol, and isopropanol. ChemPhysChem, 2005; 6(3):487–495; doi: 10.1002/cphc.200400412.

19.

Kawasaki

, Hatase

, Fujii

, et al. The distribution of chiral asymmetry in meteorites: An investigation using asymmetric autocatalytic chiral sensors. Geochim Cosmochim Acta, 2006; 70(21):5395–5402; doi: 10.1016/j.gca.2006.08.006.

20.

Kayanuma

, Kidachi

, Shoji

, et al. A theoretical study of the formation of glycine via hydantoin intermediate in outer space environment. Chem Phys Lett, 2017; 687:178–183; doi: 10.1016/j.cplett.2017.09.016.

21.

Kondepudi

, Kaufman

, Singh

Chiral symmetry breaking in sodium chlorate crystallizaton. Science, 1990; 250(4983):975–976; doi: 10.1126/science.250.4983.975.

22.

Kröner

Laser-driven electron dynamics for circular dichroism in mass spectrometry: From one-photon excitations to multiphoton ionization. Phys Chem Chem Phys, 2015; 17(29):19643–19655; doi: 10.1039/c5cp02193f.

23.

Kwon

, Tamura

, Lucas

, et al. Near-infrared circular polarization images of Ngc 6334-V. Astrophys J, 2013; 765(1):L6; doi: 10.1088/2041-8205/765/1/L6.

24.

Kwon

, Tamura

, Hough

, et al. Near-infrared circular polarization survey in star-forming regions: Correlations and trends. Astrophys J, 2014; 795(1):L16; doi: 10.1088/2041-8205/795/1/L16.

25.

Kwon

, Tamura

, Hough

, et al. Near-infrared circular and linear polarimetry of Monoceros R2. Astron J, 2016; 152(3):67; doi: 10.3847/0004-6256/152/3/67.

26.

Kwon

, Nakagawa

, Tamura

, et al. Near-infrared polarimetry of the outflow source AFGL 6366S: Detection of circular polarization. Astron J, 2018; 156(1):1; doi: 10.3847/1538-3881/aac389.

27.

McGuire

, Carroll

, Loomis

, et al. Discovery of the interstellar chiral molecule propylene oxide (CH₃CHCH₂O). Science, 2016; 352(6292):1449–1452; doi: 10.1126/science.aae0328.

28.

Meierhenrich

, Nahon

, Alcaraz

, et al. Asymmetric vacuum UV photolysis of the amino acid leucine in the solid state. Angew Chem Int Ed Engl, 2005; 44(35):5630–5634; doi: 10.1002/anie.200501311.

29.

Meierhenrich

, Filippi

, Meinert

, et al. Photolysis of rac-leucine with circularly polarized synchrotron radiation. Chem Biodivers, 2010; 7(6):1651–1659; doi: 10.1002/cbdv.200900311.

30.

Meinert

, Hoffmann

, Cassam-Chenaï

, et al. Photonenergy-controlled symmetry breaking with circularly polarized light. Angew Chem Int Ed Engl, 2014; 53(1):210–214; doi: 10.1002/anie.201307855.

31.

Meinert

, Cassam-Chenaï

, Jones

, et al. Anisotropy-guided enantiomeric enhancement in alanine using far-UV circularly polarized light. Orig Life Evol Biosph, 2015; 45:149–161; doi: 10.1007/s11084-015-9413-x.

32.

Miyahara

, Hasegawa

, Nakatsuji

Circular dichroism and absorption spectroscopy for three-membered ring compounds using symmetry-adapted cluster-configuration interaction (SAC-CI) method. Bull Chem Soc Jpn, 2009; 82(10):1215–1226; doi: 10.1246/bcsj.82.1215.

33.

Nuevo

, Meierhenrich

, d'Hendecourt

, et al. Enantiomeric separation of complex organic molecules produced from irradiation of interstellar/circumstellar ice analogs. Adv Space Res, 2007; 39(3):400–404; doi: 10.1016/j.asr.2005.05.011.

34.

Paulson

, Murray

, Bennett

, et al. Photochemistry of epoxides. 3. Direct irradiation of propylene oxide in the gas phase. J Org Chem, 1977; 42,(7):1252–1254; doi: 10.1021/jo00427a035.

35.

Rizzo

, Vahtras

. Ab initio study of excited state electronic circular dichroism. Two prototype cases: Methyl oxirane and R-(+)-1,1′-bi(2-naphthol). J Chem Phys, 2011; 134:244109; doi: 10.1063/1.3602219.

36.

Sato

, Kitazawa

, Ochi

, et al. First-principles study of the formation of glycine-producing radicals from common interstellar species. Mol Astrophys, 2018; 10:11–19; doi: 10.1016/j.molap.2018.01.002.

37.

Shibuya

, Ouchi

, Nakajima

, et al. What is the physical origin of strong Lyα emission? II. Gas kinematics and distribution of Lyα emitters. Astrophys J, 2014; 788(1):74; doi: 10.1088/0004-637X/788/1/74.

38.

Shoji

, Watanabe

, Hori

, et al. Comprehensive search of stable isomers of alanine and alanine precursors in prebiotic syntheses. Astrobiol, 2022; 22(9): Ahead of Print; doi: 10.1089/ast.2022.0011.

39.

Snow

, Howard

, Evangelisti

, et al. From transient to induced permanent chirality in 2-propanol upon dimerization: A rotational study. J Phys Chem A, 2011; 115(1):47–51; doi: 10.1021/jp1107944.

40.

Soai

, Shibata

, Morioka

, et al. Asymmetric autocatalysis and amplification of enantiomeric excess of a chiral molecule. Nature, 1995; 378:767–768; doi: 10.1038/378767a0.

41.

Tia

, Cunha de Miranda

, Daly

, et al. VUV photodynamics and chiral asymmetry in the photoionization of gas phase alanine enantiomers. J Phys Chem A, 2014; 118(15):2765–2779; doi: 10.1021/jp5016142.

42.

Turner

, Apponi

. Microwave detection of interstellar vinyl alcohol, CH₂ = CHOH. Astrophys J, 2001; 561(2):L207–L210; doi: 10.1086/324762.

43.

Varsano

, Espinosa-Leal

, Andrade

, et al. Towards a gauge invariant method for molecular chiroptical properties in TDDFT. Phys Chem Chem Phys, 2009; 11:4481–4489; doi: 10.1039/B903200B.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.27 MB

0.19 MB

Theoretical Investigation into a Possibility of Formation of Propylene Oxide Homochirality in Space

Abstract

1. Introduction

2. Methods

2.1. Computational details

2.2. Selection of reaction pathways

3.1. Reaction pathways

Path A

Path B

Path C

Footnotes

Acknowledgments

Authorship Confirmation Statement

Authors' Disclosure Statement

Funding Statement

Supplementary Material

Abbreviations Used

References

Supplementary Material