The 130–500 GHz rotational spectrum of 2-cyanopyrimidine

Millimeter-Wave and High-Resolution Infrared Spectroscopy of 2-Furonitrile─A Highly Polar Substituted Furan

“…The recently expanded frequency range of our instrument allowed us to measure the rotational spectrum of 2-furonitrile up to 750 GHz, a frequency coverage well beyond that used in some of our previous works on cyanoarenes (up to 375 GHz − or up to 500 GHz , ). Spectral coverage up to 750 GHz is the nearly optimal range at ambient laboratory temperature (Figure ), capturing nearly all of the most intense a - and b -type transitions for 2-furonitrile.…”

“…A unifying feature of the spectra of cyanoarenes is the a - and/or b -axis Coriolis-coupled dyad of their two lowest-energy fundamental states, the out-of-plane and in-plane vibrations of the nitrile group. As with these previous studies, − we report the rotational spectra of the ground vibrational state and the Coriolis-coupled dyad of the two lowest-energy fundamental vibrational modes (ν 24 and ν 17 ). We also present a preliminary analysis of the third fundamental mode, ν 23 .…”

“…Cyano substitution of benzene and naphthalene was critical to this conclusion, as neither parent species has a permanent dipole moment. The recent works on cyanoarenes may lead to the eventual detection of these species, − providing similarly strong evidence for the presence of their parent heterocycles (pyridine, pyrimidine, and pyrazine). To provide similar laboratory data for the astronomical community, we investigated the rotational spectra of the two regioisomeric furonitriles (cyanofurans) (Figure ).…”

“…9 While its relatively weak permanent dipole moment makes the detection of furan more challenging, molecules with similar dipoles have been detected in extraterrestrial sources, e.g., cyclopentadiene 17 and indene. 18 Motivated by the recent detections of aromatic nitriles, 16,19−21 as well as the variety and abundance of nitrilecontaining molecules detected in extraterrestrial sources, 22,23 we have investigated the rotational spectra of several six-membered ring aromatic and heteroaromatic nitriles, i.e., benzonitrile, 24,25 three cyanopyridines, 26−28 cyanopyrimidine, 29 and cyanopyr-azine. 30 The radioastronomical detections of benzonitrile 16,19 and cyanonaphthalenes 19,20 provide strong evidence for the existence of benzene and naphthalene in the ISM.…”

“…Motivated by the recent detections of aromatic nitriles, ,− as well as the variety and abundance of nitrile-containing molecules detected in extraterrestrial sources, , we have investigated the rotational spectra of several six-membered ring aromatic and heteroaromatic nitriles, i.e. , benzonitrile, , three cyanopyridines, − cyanopyrimidine, and cyanopyrazine . The radioastronomical detections of benzonitrile , and cyanonaphthalenes , provide strong evidence for the existence of benzene and naphthalene in the ISM.…”