Molecular and electronic structures of acryloyl isothiocyanate, CH2CHC(O)NCS: a joint experimental and theoretical study

Acryloyl isothiocyanate, CH2CHC(O)NCS, was prepared and studied by IR, Raman, photoelectron spectroscopy (PES), photoionization spectroscopy (PIMS) and theoretical calculations. This molecule was theoretically predicted to prefer the trans-cis (tc) conformation as the most stable conformer, with the CO bond trans to the CC bond and cis to the NCS group. IR and Raman spectra also suggest the presence of the tc conformation only. A theoretical study involving the calculation of the ionization energies using the orbital valence Green's functional (OVGF/6-311+G(d)) was performed to aid the assignment of the PE spectrum. The first vertical ionization energy of CH2CHC(O)NCS was determined to be 9.89 eV, which is mainly the ionization of the out-of-plane bonding πNCS orbital. Natural population analysis (NPA and NBO) were also performed to investigate the reactivity of CH2CHC(O)NCS.