Excited-State Properties of a (2,2'-Bypiridine)ruthenium(II) Complex, 2-, a Model of Localized Excitation

Article abstract of DOI:10.1021/j100346a010

The excited-state properties of a mono complex, ^2-, have been investigated as a model of a tris complex, ²⁺, with completely localized excitation.The mono complex shows strong solvent dependence in both absorption and emission spectra.Larger temperature and time dependences of the emission spectrum were observed in the range 100-150 K.The emission spectrum shifts to a longer wavelength side at higher temperatures or at later times.An edge excitation red shift was also observed in this system.These results are mostly interpreted by solvent reorientation in the excited states.The decay rate constant of the mono complex was found to be remarkably dependent on temperature (1.3E4 s^-1 at 4.2 K and 3.0E5 s^-1 at 77 K), which can be analyzed in terms of the three emitting states separated by 8 and 53 cm^-1 from the lowest one.It was found that the properties of the mono complex are very similar to those of the tris complex.From these results, it is concluded that the excitation is localized on a single bpy ligand for the tris complex not only in liquid solutions but also in rigid media.