title: Laboratory observation of the valence anion of cyanoacetylene, a possible precursor for negative ions in space.
abstract: Valence anions of cyanoacetylene, HCCCN(-), are synthesized by the 1,2-H(2) (+) abstraction reaction of O(-) with acrylonitrile, H(2)C=CHCN, while the competing 1,1-H(2) (+) channel of the same reaction yields the cyanovinylidene anions, CCHCN(-). The key to the formation of the elusive, adiabatically weakly bound HCCCN(-) is the bent -C=C-C[triple bond]skeleton of the reactant. The photoelectron spectrum of HCCCN(-), measured by means of photoelectron imaging at 532 nm, consists of a broad structureless band with a vertical detachment energy of 1.04+/-0.05 eV. The observed anions are stable counterparts of the low-lying anionic resonances of cyanoacetylene, which may contribute (by way of dissociative attachment) to the formation of carbon-rich and CN-containing negative ions in extraterrestrial environments.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721-0041, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Goebbert
authors.forename: Dmitry
authors.initials: D
authors.lastname: Khuseynov
authors.forename: Andrei
authors.initials: A
authors.lastname: Sanov