COMPUTATIONAL AND EXPERIMENTAL STUDIES OF CHROMIUM-PAH COMPLEXES

A series of Cr-PAH complexes are studied with the size of PAH increasing from benzene to naphthalene, to pyrene, and to coronene. Both the mono-PAH and bis-PAH complexes are studied with density functional theory (DFT). Three typical DFT methods are used in this study, including B3LYP, PBE, and M06L. Geometries, spin states, binding energies, and ionization potentials are investigated theoretically. Cr is found to prefer the binding on the six-member rings with less shared carbons. It may bind to PAHs on either the eta-2 or eta-6 position. The mono-PAH complexes prefer high spin states, and the bis-PAH complexes prefer low spin states. The trend of binding energies of Cr to these PAHs is not apparent from the calculations. Complexes with larger PAHs have lower ionization potentials. The laser vaporization flowtube reactor (LVFR) is used to synthesize Cr-coronene complexes. The mass spectra indicate these complexes are successfully made in the LVFR.