Electronic spectra of tris(2,2'-bipyridine)-metal complex ions in gas phase

Tris(bpy)-metal complexes (bpy = 2,2'-bipyridine) and their derivatives are important systems in metal-organic chemistry. While tris(bpy)-ruthenium, \chem{Ru(bpy)_{3}^{2+}}, has been extensively studied, less attention has been paid to analogous complexes involving first row transition metals. Here we report the electronic spectra of a series of dicationic tris(bpy) chelates with different transition metals, measured by photodisscociation spectroscopy of cryogenically prepared ions. We focus our attention on the $\pi$-$\pi$ transitions in the UV region of the spectrum