Photoelectron Spectrum and Energetics of the meta-Xylylene Diradical

Authors

Mathias Steglich, Paul Scherrer Institute
Victoria Custodis, ETH Zurich
Adam J. Trevitt, University of WollongongFollow
Gabriel da Silva, University of MelbourneFollow
A Bodi, Paul Scherrer Institute
Patrick Hemberger, Paul Scherrer InstituteFollow

RIS ID

117017

Publication Details

Steglich, M., Custodis, V. B. F., Trevitt, A. J., daSilva, G., Bodi, A. & Hemberger, P. (2017). Photoelectron Spectrum and Energetics of the meta-Xylylene Diradical. Journal of the American Chemical Society, 139 (41), 14348-14351.

Abstract

The meta-xylylene diradical m-C₈H₈ is a prototypical organic triplet that represents a building block for organic molecule-based magnets and also serves as a model compound for test and refinement of quantum chemical calculations. Flash vacuum pyrolysis of 1,3-bis-iodomethyl-benzene (m-C₈H₈I₂) produces m-C 8 H 8 in gas phase; we used photoelectron spectroscopy to probe the first two electronic states of the radical cation, and resolve the vibrational fine structure of the ground state band. The determined adiabatic ionization energy of m-C₈H₈ is (7.27 ± 0.01) eV. Heat of formation of the diradical was established measuring C-I bond dissociation thresholds in the precursor cation and utilizing a thermochemical cycle to yield ΔH_f,298K = (325 ± 8) kJ mol^-1 , ca. 10 kJ mol^-1 below the previous value.