Lifetimes of the ligand-to-metal charge-transfer excited states of iron(III) and osmium(III) polypyridine complexes. Effects of isotopic substitution and temperature

Journal Article · Thu Sep 29 04:00:00 EDT 1983 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100243a018· OSTI ID:5434030

Bergkamp, M A; Guetlich, P; Netzel, T L; Sutin, N

The lifetimes of the ligand-to-metal charge-transfer (LMCT) excited states produced by 527-nm excitation of M(phen)/sub 3//sup 3 +/ and M(bpy)/sub 3//sup 3 +/ (M = Fe or Os (iron or osmium); phen = 1,10-phenanthroline; bpy = 2,2'-bipyridine) are reported at temperatures between 10 and 295 K and are compared to the low-temperature lifetimes of the metal-to-ligand charge-transfer (MLCT) excited states of the corresponding M(phen)/sub 3//sup 2 +/ and M(bpy)/sub 3//sup 2 +/ complexes. The observations that the MLCT states of the Osmium(II) complexes are 10/sup 5/-10/sup 6/ times longer-lived than the LMCT states of the Os(III) complexes (microseconds vs. picoseconds) and that the lifetimes of both types of charge-transfer states are increased less than a factor of 3 upon deuteration are rationalized in terms of radiationless-decay theory. The dominant active modes for both types of charge-transfer states appear to be intermediate-frequency (1300 to 1600 cm/sup -1/) vibrations and it is proposed that the shorter lifetimes of the Os(III) complexes are mainly a consequence of their smaller energy gaps. 5 figures, 3 tables.

• Research Organization: Brookhaven National Lab., Upton, NY
• OSTI ID: 5434030
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 87:20; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ABSORPTION SPECTRA
AROMATICS
AZAARENES
AZINES
BIPYRIDINES
CHARGE EXCHANGE
COMPLEXES
DATA
DEUTERIUM
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
IONIZATION
IRON COMPLEXES
ISOTOPE EFFECTS
ISOTOPES
LIGANDS
LIGHT NUCLEI
LOW TEMPERATURE
MEDIUM TEMPERATURE
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OSMIUM COMPLEXES
PHENANTHROLINES
PHOTOIONIZATION
PYRIDINES
SPECTRA
STABLE ISOTOPES
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRANSITION ELEMENT COMPLEXES
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE