Electronic energy transfer from the charge-transfer excited states of ruthenium(II) polypyridyl complexes to the ligand field excited states of chromium(III). Weakly coupled small energy gap behavior for bimolecular reactions
Interpretation of the rate patterns previously reported for the energy-transfer quenching of (*CT)Ru(bpy)/sub 3//sup 2 +/ and (*CT)-Ru(bpy)/sub 2/(CN)/sub 2/ (bpy = 2,2'-bipyridyl) donors by chromium(III) complexes is generally complicated by appreciable overlap of the donor (*CT ..-->.. /sup 1/A/sub 1/) emission and the acceptor (/sup 4/T/sub 2/ reverse arrow /sup 4/A/sub 2/) absorbance. To avoid the resulting ambiguities of interpretation, rate patterns have been determined for a series of Cr(III) amine and cyanoamine complexes for which the spectral overlap is very small and only doublet acceptor states are energetically accessible. The resulting quenching rates are much smaller than the expected diffusion limit, and they tend to increase in proportion to the donor-acceptor energy gap, ..delta.. E. This is an expected result for ..delta.. E less than the energies of available acceptor vibrational modes due to the increase of the density of acceptor states with increasing ..delta.. E. When there is appreciable donor-acceptor spectral overlap, a quartet quenching channel appears to compete, with the net quenching rate a composite of the doublet and quartet channels. 39 references, 5 figures, 1 table.
- Research Organization:
- Wayne State Univ., Detroit, MI
- OSTI ID:
- 6037411
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 90:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CHROMIUM COMPLEXES
EXCITED STATES
RADIATIONLESS DECAY
PYRIDINES
RUTHENIUM COMPLEXES
ABSORPTION
ADDUCTS
ELECTRON TRANSFER
EMISSION
ENERGY TRANSFER
EXPERIMENTAL DATA
LIGANDS
AZINES
COMPLEXES
DATA
DE-EXCITATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
HETEROCYCLIC COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
TRANSITION ELEMENT COMPLEXES
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)