Photodriven Electron and Energy Transfer from Copper Phenanthroline Excited States

Abstract

Electron and energy transfer from copper 1,10-phenanthroline excited states is observed at room temperature in organic solvents. The copper phenanthroline excited states are metal-to-ligand charge-transfer in nature and have lifetimes of approximately 70-250 ns in dichloromethane solution if methyl or phenyl substituents are placed in the 2- and 9-positions of the phenanthroline ligand. The unsubstituted cuprous compound Cu(phen)(2)(PF(6)) is nonemissive under these conditions, and the excited state lifetime is <20 ns. The rate and efficiency of energy transfer to anthracene or electron transfer to viologens is reported. The cage escape efficiency of [Cu(dpp)(2)(2+), MV(+)(*)], where dpp is 2,9-diphenyl-1,10-phenanthroline, is close to unity within experimental error. Back electron transfer to ground state products occurs at the diffusion limit, 2 x 10(10) M(-)(1) s(-)(1).

Ultrafast dynamics in Cu(I)bisdiimine complexes from resonance Raman intensities

“…45 Each complex was prepared by adding two equivalents of the appropriate ligand to the tetraacetonitrilecopper(I) tetrafluoroborate precursor. 45 Each complex was prepared by adding two equivalents of the appropriate ligand to the tetraacetonitrilecopper(I) tetrafluoroborate precursor.…”

Cu(I)-2,9-dimethyl-1,10-phenanthroline: Density functional study of the structure, vibrational force-field, and excited electronic states

“…7,26,27 It is however possible that intermolecular forces in a crystal are responsible for these deviations since proton nuclear magnetic resonance ͑NMR͒ spectra of these complexes in solution indicate equivalence of the two ligands on the NMR time scale at room temperature. 28 Lability of ligands in solution was experimentally observed 29 which indicates that the Cu͑I͒-L bond is not very strong resulting in presumably low harmonic frequency for the Cu͑I͒-L stretching motions. No experimental data on Cu͑I͒ atom motion in the complex are currently available.…”

Heteroleptic Copper Switches

“…34,57,58 The relatively high Cu(RM) 2 2+/+ and Cu(RL) 2 2+/+ couples compared to the Cu(phen)) 2 2+/+ couple can be attributed to the additional electron donating groups provided by the trityl acetylene and 4-ethynyl-biphenyl groups from RM and RL, resepectively. 57 …”