Selective deprotonation of oxazole and photoelectron imaging of the oxazolide anion

Abstract

A photoelectron imaging study of the oxazolide anion obtained by selective deprotonation of oxazole at the C2 position is reported. The photodetachment transitions observed at 355, 392, and 532 nm are assigned to the ground state of the neutral oxazolyl σ radical. A Franck–Condon analysis of this transition aids in the first determination of the adiabatic electron affinity of oxazolyl, EA = 2.21 ± 0.02 eV. A vibrational progression with a frequency of 890 ± 80 cm⁻¹ is observed, corresponding to an in-plane ring distortion mode. The photoelectron angular distributions are analyzed using the mixed s–p model, shedding light on the hybrid character of the anion HOMO.