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Interstellar detection of the highly polar five-membered ring cyanocyclopentadiene

Abstract

Much like six-membered rings, five-membered rings are ubiquitous in organic chemistry, frequently serving as the building blocks for larger molecules, including many of biochemical importance. From a combination of laboratory rotational spectroscopy and a sensitive spectral line survey in the radio band toward the starless cloud core TMC-1, we report the astronomical detection of 1-cyano-1,3-cyclopentadiene (1-cyano-CPD, c-C5H5CN), a highly polar, cyano derivative of cyclopentadiene. The derived abundance of 1-cyano-CPD is far greater than predicted from astrochemical models that well reproduce the abundance of many carbon chains. This finding implies that either an important production mechanism or a large reservoir of aromatic material may need to be considered. The apparent absence of its closely related isomer, 2-cyano-1,3-cyclopentadiene, may arise from that isomer’s lower stability or may be indicative of a more selective pathway for formation of the 1-cyano isomer, perhaps one starting from acyclic precursors. The absence of N-heterocycles such as pyrrole and pyridine is discussed in light of the astronomical finding of 1-cyano-CPD.

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Fig. 1: Geometric structures of the two low-lying cyano-CPD isomers, along with their relative stabilities calculated theoretically at the G3//B3LYP level of theory.
Fig. 2: Velocity-stacked spectra of 1-cyano-CPD and 2-cyano-CPD and the impulse response function of the stacked spectra.
Fig. 3: Abundance predictions for 1-cyano-CPD and 2-cyano-CPD from two chemical models in comparison with those derived from observations of TMC-1.

Data availability

The datasets analysed during the current study are available in the Green Bank Telescope archive (https://archive.nrao.edu/archive/advquery.jsp). A user manual for their reduction and analysis is available as well (https://greenbankobservatory.org/science/gbt-observers/visitor-facilities-policies/data-reduction-gbt-using-idl/). The complete, reduced survey data in the X band are available as supplementary information in ref. 15. The individual portions of reduced spectra used in the analysis of the individual species presented here are available in the Harvard Dataverse archive26.

Code availability

All the codes used in the MCMC fitting and stacking analysis presented in this paper are open source and publicly available at https://github.com/ryanaloomis/TMC1_mcmc_fitting.

References

  1. 1.

    McGuire, B. A. et al. Detection of the aromatic molecule benzonitrile (c-C6H5CN) in the interstellar medium. Science 359, 202–205 (2018).

    ADS  Article  Google Scholar 

  2. 2.

    Lipkus, A. H. et al. Structural diversity of organic chemistry. A scaffold analysis of the CAS registry. J. Org. Chem. 73, 4443–4451 (2008).

    Article  Google Scholar 

  3. 3.

    Ruddigkeit, L., van Deursen, R., Blum, L. C. & Reymond, J.-L. Enumeration of 166 billion organic small molecules in the chemical universe database GDB-17. J. Chem. Inf. Model. 52, 2864–2875 (2012).

    Article  Google Scholar 

  4. 4.

    McGuire, B. A. 2018 census of interstellar, circumstellar, extragalactic, protoplanetary disk, and exoplanetary molecules. Astrophys. J. Suppl. Ser. 239, 17 (2018).

    ADS  Article  Google Scholar 

  5. 5.

    Laurie, V. W. Microwave spectrum and dipole moment of cyclopentadiene. J. Chem. Phys. 24, 635–636 (1956).

    ADS  Article  Google Scholar 

  6. 6.

    Damiani, D., Ferretti, L. & Gallinella, E. Structure of cyclopentadiene from microwave spectra of several deuterated species. Chem. Phys. Lett. 37, 265–269 (1976).

    ADS  Article  Google Scholar 

  7. 7.

    Turro, N. J. & Hammond, G. S. The photosensitited dimerization of cyclopentadiene. J. Am. Chem. Soc. 84, 2841–2842 (1962).

    Article  Google Scholar 

  8. 8.

    Werner, H. At least 60 years of ferrocene: the discovery and rediscovery of the sandwich complexes. Angew. Chem. Int. Ed. 51, 6052–6058 (2012).

    Article  Google Scholar 

  9. 9.

    Dalkílíç, E. & Daştan, A. Synthesis of cyclopentadiene derivatives by retro-Diels–Alder reaction of norbornadiene derivatives. Tetrahedron 71, 1966–1970 (2015).

    Article  Google Scholar 

  10. 10.

    Wentrup, C. & Crow, W. Structures of cyanocyclopentadienes and related compounds. Tetrahedron 26, 4375–4386 (1970).

    Article  Google Scholar 

  11. 11.

    McCarthy, M. C. et al. Exhaustive product analysis of three benzene discharges by microwave spectroscopy. J. Phys. Chem. A 124, 5170–5181 (2020).

    Article  Google Scholar 

  12. 12.

    Ford, R. G. & Seitzman, H. A. The microwave spectrum and dipole moment of 1-cyano-1,3-cyclopentadiene. J. Mol. Spectrosc. 69, 326–329 (1978).

    ADS  Article  Google Scholar 

  13. 13.

    Sakaizumi, T., Kikuchi, H., Ohashi, O. & Yamaguchi, I. The microwave spectra, dipole moments, and two isomers of cyclopentadiene-1-carbonitrile. Bull. Chem. Soc. Jpn. 60, 3903–3909 (1987).

    Article  Google Scholar 

  14. 14.

    Kaifu, N. et al. A 8.8–50 GHz complete spectral line survey toward TMC-1 I. Survey data. Publ. Astron. Soc. Jpn. 56, 69–173 (2004).

    ADS  Article  Google Scholar 

  15. 15.

    McGuire, B. A. et al. Early science from GOTHAM: project overview, methods, and the detection of interstellar propargyl cyanide (HCCCH2CN) in TMC-1. Astrophys. J. Lett. 900, L10 (2020).

    ADS  Article  Google Scholar 

  16. 16.

    Dobashi, K. et al. Spectral tomography for the line-of-sight structures of the Taurus Molecular Cloud 1. Astrophys. J. 864, 82 (2018).

    ADS  Article  Google Scholar 

  17. 17.

    Dobashi, K. et al. Discovery of CCS velocity-coherent substructures in the Taurus Molecular Cloud 1. Astrophys. J. 879, 88 (2019).

    ADS  Article  Google Scholar 

  18. 18.

    Simmie, J. M. & Somers, K. P. Benchmarking compound methods (CBS-QB3, CBS-APNO, G3, G4, W1BD) against the active thermochemical tables: a litmus test for cost-effective molecular formation enthalpies. J. Phys. Chem. A 119, 7235–7246 (2015).

    Article  Google Scholar 

  19. 19.

    Lee, K. L. K., McGuire, B. A. & McCarthy, M. C. Gas-phase synthetic pathways to benzene and benzonitrile: a combined microwave and thermochemical investigation. Phys. Chem. Chem. Phys. 21, 2946–2956 (2019).

    Article  Google Scholar 

  20. 20.

    Xue, C. et al. Detection of interstellar HC4NC and an investigation of isocyanopolyyne chemistry in TMC-1 conditions. Astrophys. J. Lett. 900, L9 (2020).

    ADS  Article  Google Scholar 

  21. 21.

    Shingledecker, C. N., Molpeceres, G., Rivilla, V. M., Majumdar, L. & Kaestner, J. Isomers in interstellar environments (I): the case of Z- and E-cyanomethanimine. Astrophys. J. (in the press).

  22. 22.

    Nelson, R. D. Jr, Lide, D. R. & Maryott, A. A. Selected Values of Electric Dipole Moments for Molecules in the Gas Phase National Standard Reference Data Series—National Bureau of Standards 10 (US Department of Commerce National Bureau of Standards, 1967).

  23. 23.

    Lee, K. L. K., McGuire, B., Burkhardt, A. & McCarthy, M. C. Interstellar aromatic chemistry: a combined laboratory, observational, and theoretical perspective. In Laboratory Astrophysics (IAU S350): from Observations to Interpretation (eds Salama, F. & Linnartz, H.) (Cambridge Univ. Press, in the press).

  24. 24.

    Turner, B. E. A molecular line survey of Sagittarius B2 and Orion-KL from 70 to 115 GHz. II—Analysis of the data. Astrophys. J. Suppl. Ser. 76, 617–686 (1991).

  25. 25.

    Gratier, P. et al. A new reference chemical composition for TMC-1. Astrophys. J. Suppl. Ser. 225, 1110 (2016).

    Article  Google Scholar 

  26. 26.

    GOTHAM Collaboration. Spectral stacking data for Phase 1 science release of GOTHAM. Harvard Dataverse V4 https://doi.org/10.7910/DVN/PG7BHO (2020).

  27. 27.

    Balucani, N. et al. Formation of nitriles in the interstellar medium via reactions of cyano radicals, CN(X 2Σ+), with unsaturated hydrocarbons. Astrophys. J. 545, 892–906 (2000).

    ADS  Article  Google Scholar 

  28. 28.

    Woods, P. M., Millar, T. J., Zijlstra, A. A. & Herbst, E. The synthesis of benzene in the proto-planetary nebula CRL 618. Astrophys. J. 574, L167–L170 (2002).

    ADS  Article  Google Scholar 

  29. 29.

    Cooke, I. R., Gupta, D., Messinger, J. P. & Sims, I. R. Benzonitrile as a proxy for benzene in the cold ISM: low temperature rate coefficients for CN + C6H6. Astrophys. J. Lett. 891, L41 (2020).

    ADS  Article  Google Scholar 

  30. 30.

    Zimmerman, P. M. Growing string method with interpolation and optimization in internal coordinates: method and examples. J. Chem. Phys. 138, 184102 (2013).

    ADS  Article  Google Scholar 

  31. 31.

    Zimmerman, P. M. Automated discovery of chemically reasonable elementary reaction steps. J. Comput. Chem. 34, 1385–1392 (2013).

    Article  Google Scholar 

  32. 32.

    Jafari, M. & Zimmerman, P. M. Reliable and efficient reaction path and transition state finding for surface reactions with the growing string method. J. Comput. Chem. 38, 645–658 (2017).

    Article  Google Scholar 

  33. 33.

    Bouwman, J., Bodi, A., Oomens, J. & Hemberger, P. On the formation of cyclopentadiene in the C3H5 + C2H2 reaction. Phys. Chem. Chem. Phys. 17, 20508–20514 (2015).

    Article  Google Scholar 

  34. 34.

    Shingledecker, C. N., Tennis, J., Gal, R. L. & Herbst, E. On cosmic-ray-driven grain chemistry in cold core models. Astrophys. J. 861, 20 (2018).

    ADS  Article  Google Scholar 

  35. 35.

    Shingledecker, C. N. & Herbst, E. A general method for the inclusion of radiation chemistry in astrochemical models. Phys. Chem. Chem. Phys. 20, 5359–5367 (2018).

    Article  Google Scholar 

  36. 36.

    Ruaud, M., Wakelam, V. & Hersant, F. Gas and grain chemical composition in cold cores as predicted by the Nautilus three-phase model. Mon. Not. R. Astron. Soc. 459, 3756–3767 (2016).

    ADS  Article  Google Scholar 

  37. 37.

    Wakelam, V. et al. The 2014 KIDA network for interstellar chemistry. Astrophys. J. Suppl. Ser. 217, 20 (2015).

    ADS  Article  Google Scholar 

  38. 38.

    Trevitt, A. J., Goulay, F., Taatjes, C. A., Osborn, D. L. & Leone, S. R. Reactions of the CN radical with benzene and toluene: product detection and low-temperature kinetics. J. Phys. Chem. A 114, 1749–1755 (2010).

    Article  Google Scholar 

  39. 39.

    Woon, D. E. & Herbst, E. Quantum predictions of the properties of known and postulated neutral interstellar molecules. Astrophys. J. Suppl. Ser. 185, 273–288 (2009).

    ADS  Article  Google Scholar 

  40. 40.

    Loomis, R. A. et al. Non-detection of HC11N towards TMC-1: constraining the chemistry of large carbon-chain molecules. Mon. Not. R. Astron. Soc. 463, 4175–4183 (2016).

    ADS  Article  Google Scholar 

  41. 41.

    Hincelin, U. et al. Oxygen depletion in dense molecular clouds: a clue to a low O2 abundance? Astron. Astrophys. 530, A61 (2011).

    Article  Google Scholar 

Download references

Acknowledgements

M.C.M. and K.L.K.L. acknowledge support from National Science Foundation (NSF) grant AST-1908576 and NASA grant 80NSSC18K0396. A.M.B. acknowledges support from the Smithsonian Institution as a Submillimeter Array Fellow. C.N.S. thanks the Alexander von Humboldt Stiftung/Foundation for their generous support, as well as V. Wakelam for use of the NAUTILUS v1.1 code. S.B.C. and M.A.C. were supported by the NASA Astrobiology Institute through the Goddard Center for Astrobiology. E.H. thanks the NSF for support through grant AST-1906489. C.X. is a Grote Reber Fellow, and support for this work was provided by the NSF through the Grote Reber Fellowship Program administered by Associated Universities, Inc./National Radio Astronomy Observatory and the Virginia Space Grant Consortium. Support for B.A.M. was provided by NASA through Hubble Fellowship grant HST-HF2-51396 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. The National Radio Astronomy Observatory is a facility of the NSF operated under cooperative agreement by Associated Universities, Inc. The Green Bank Observatory is a facility of the NSF operated under cooperative agreement by Associated Universities, Inc.

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Authors

Contributions

M.C.M. and K.L.K.L. performed the laboratory experiments and theoretical calculations and wrote the paper with the help of A.M.B. and C.N.S. A.M.B, B.A.M., A.J.R. and R.A.L. performed the astronomical observations and subsequent analysis. E.H. determined and/or estimated rate coefficients and is the originator of many of the chemical simulations. A.M.B. and C.N.S. contributed or undertook the astronomical modelling and simulations. E.R.W., M.A.C., S.B.C., S.K., C.X., B.A.M., A.J.R. and R.A.L. contributed to the design of the GOTHAM survey, and helped revise the manuscript.

Corresponding authors

Correspondence to Michael C. McCarthy or Brett A. McGuire.

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Extended data

Extended Data Fig. 1 Spectral data.

Total number of transitions of a given species within the range of the GOTHAM data, number of interfering lines, and total number included in MCMC fit.

Extended Data Fig. 2 Thermochemistry (0 K) for the reaction between CN radical and CPD.

The calculated has been performed at the G3//B3LYP level of theory, and energies in kJ/mol are given relative to the reactant asymptote. The reaction bifurcates as CN attacks CPD barrierlessly, forming a radical intermediate. Subsequent hydrogen atom loss yields 1-cyano- and 2-cyano-CPD.

Extended Data Fig. 3 Potential energy surface for the formation of CPD at 0 K.

Reaction energies are given relative to the product (CPD + H atom) asymptote. The red trace corresponds to reaction between propargyl radical (HCCCH2) and ethylene (H2C=CH2), and the blue trace represents gauche-butadiene (H2C(CH)2CH2) reacting with CH radical.

Supplementary information

Supplementary Information

Supplementary Tables 1–5, Figs. 1–6 and text.

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McCarthy, M.C., Lee, K.L.K., Loomis, R.A. et al. Interstellar detection of the highly polar five-membered ring cyanocyclopentadiene. Nat Astron 5, 176–180 (2021). https://doi.org/10.1038/s41550-020-01213-y

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