Gas-phase reactivity of hexanuclear molybdenum [Mo

The optical properties, photo-decomposition and photo-reactivity of [Mo6I14]2- clusters and their associated photo-products are examined in the gas phase. The UV-visible optical spectrum of the electron-rich [Mo6I14]2- cluster is measured and the wavelength dependence of the principal fragments is interpreted on the basis of the quantum chemistry (QC) simulated spectrum and detailed transitions. A special focus of attention is the photo-generated [Mo6I14]- and photo-specific radical [Mo6I13]2-˙ as well as halogen-depleted clusters [Mo6In]- with n < 14. The fragmentation and reaction energetics of all species are examined with a combination of mass spectrometry experiments, ion-molecule reactions with O2 and CO2 under irradiation and QC simulations. Reactions with O2 are shown to be very exergonic with up to 5 eV release when O2 is dissociated on the cluster. Experimental evidence for the photo-decomposition of CO2 into CO and O on [Mo6In]- ions is provided together with detailed QC energetics.