LUMINESCENT PHOTOFRAGMENTS OF (1,1,1,5,5,5-HEXAFLUORO-2,4-PENTANEDIONATO) METAL-COMPLEXES IN THE GAS-PHASE

The luminescence that is observed under gas phase photolytic depositio n conditions is studied for Cr(hfac)(3), Ni(hfac)(2), and Pt(hfac)(2). This luminescence is analyzed under a variety of conditions, includin g the relatively high pressures of an evacuated gas cell and the colli sion-free conditions of a molecular beam. The effects of inert buffer gas are also studied. Features in these spectra indicate that, in gene ral, multiple photolysis processes occur. Some simple fragments that a re produced from these compounds are identified, including bare metal atoms (Ni, Cr), metal monofluorides (NiF, CrF), CH (in the case of Ni( hfac)(2)), and metal carbide from Pt(hfac)(2). It is postulated that t he difference in the observed photofragmentation pathway in the case o f platinum is due to sigma bonding to the beta carbon of the hfac moie ty as opposed to the bidentate bonding of the other two metals. Possib le mechanisms are presented. Detailed analysis of the spectra allows c haracterization of the internal energy of the platinum carbide photofr agment.