Photodissociation of jet-cooled acetylacetonato complexes of the first transition metals. Free metal generation and fragmentational ionization

Abstract

Photodissociation of jet-cooled acetylacetonato complexes of Sc(III), Mn(III), Fe(III), Co(III), Ni(II), Cu(II), Zn(II), Al(III), and Ga(III) is studied by multiphoton dissociation/ionization mass spectroscopy. Efficient generation of the neutral Cu atom from the Cu(II) complex is found to occur after two-photon excitation with UV light. Two-color laser photolysis shows that the Cu atom generation is due to homolytic dissociation of all the metal-ligand bonds occurring in the super-excited state of the Cu(II) complex. The threshold energy of the two-photon dissociation is obtained and the energetics of the photolysis of the Cu(II) complex is given on the basis of the results. For other metal complexes it is found that extensive fragmentational ionization takes place under a similar excitation condition to that of the Cu(II) complex while free metal atom generation does not occur. The characteristic free metal generation occurring in the Cu(II) complex is discussed in connection with the photolysis of the Cr(III) complex which was reported in a previous paper.