Ultrafast structural rearrangements in the MLCT excited state for copper(I) bis-phenanthrolines in solution.

摘要: Ultrafast excited-state structural dynamics of [Cu(I)(dmp)(2)](+) (dmp = 2,9-dimethyl-1,10-phenanthroline) have been studied to identify origins transient spectroscopic changes during the photoinduced metal-to-ligand charge-transfer (MLCT) transition that induces an electronic configuration change from Cu(I) (3d(10)) Cu(II) (3d(9)). This study has important connections with flattening Franck-Condon state tetrahedral geometry and ligation Cu(II)* solvent observed in thermally equilibrated MLCT by our previous laser-initiated time-resolved X-ray absorption spectroscopy (LITR-XAS) results. To better understand photodynamics complexes, we both [Cu(I)(dpp)(2)](+) (dpp 2,9-diphenyl-1,10-phenanthroline) solvents different dielectric constants, viscosities, thermal diffusivities spectroscopy. The spectral suggest a solvent-independent inner-sphere relaxation process is occurring despite large amplitude motions due coordinated geometry. singlet fluorescence photoexcited were measured coordinating acetonitrile, using upconversion method at emission wavelengths. At bluest wavelengths, prompt lifetime 77 fs attributed deactivation processes internal conversion intersystem crossing differentiation between flattened uncovers unexpected ultrafast [Cu(I)(dmp)(2)](+). These results provide guidance for future studies on time scale, as well synthesis toward its applications solar energy conversion.