Rotational Spectra and Interstellar Search for Chiral and Achiral Butynols and Butenols: 3‑Butyn-2-ol, 3‑Buten-2-ol, 3‑Butyn-1-ol, and 3‑Buten-1-ol

To date, only two chiral molecules have been detected
in the interstellar
medium, the small epoxide propylene oxide and chemically similar monodeuterated
ethylene oxide, despite the many chiral species found on asteroids,
comets, and meteorites. As chirality is a feature ubiquitous to all
life on Earth, this prompts the interstellar search for more chiral
species to gain insight into interstellar chemistry involving chirality.
Two such chiral species, 3-butyn-2-ol and 3-buten-2-ol, as well as
the closely related achiral species, 3-buten-1-ol and 3-butyn-1-ol,
are reasonable candidates to search for due to their relative simplicity
and added stability through intramolecular hydrogen bonding, reducing
the complications typical of increasing conformations within saturated
molecules. In this work, a custom 6.5–18 GHz chirped pulse
Fourier transform microwave (CP-FTMW) spectrometer operating with
a pulsed jet expansion sample introduction and a commercial BrightSpec
18–26 GHz CP-FTMW spectrometer (nanoMRR) operating at room
temperature were used to refine the rotational spectroscopy of this
group of species. Interstellar searches were made across well-studied
astronomical sources; however, no detections were observed. Upper
limits of these species and possible next avenues for finding chiral
species in the interstellar medium are discussed.