Infrared multiphoton spectra from metal dication complexes in the gas phase

Infrared multiphoton spectra have been recorded for the first time from metal dication complexes held in an ion trap. The photofragmentation of [M (pyridine)4] 2+ complexes has been observed in the range 920-1090 cm-1 and for M= Cu2+, Mg2+ and Zn2+. The narrow absorption features are identified as vibrational modes of the pyridine molecule and comparisons with calculations suggest that the Mg2+ and Zn2+ ion complexes have D2d (compressed tetrahedron) structures, and that the Cu2+ complex is probably square-planar (D4h).