Excited-state properties of ruthenium(II) tris chelate complexes containing the ligands 2,2'-bipyridine (bpy) and dipyrido(3,2-c:2',3'-e)pyridazine (taphen)

Journal Article · Tue Jan 28 23:00:00 EST 1986 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00223a005· OSTI ID:5889785

Jursi, A; Belser, P; Barigelletti, F; Von Zelewsky, A; Balzani, V

The complexes Ru(bpy)/sub 3-n/(taphen)/sub n//sup 2 +/ (n = 0-3, bpy = 2,2'-bipyridine, taphen = dipyrido(3,2-c:2',3'-e)pyridazine) have been prepared, and their absorption spectra, emission spectra, emission lifetimes, luminescence quantum yields, and redox potentials have been measured. The first reduction potential of the three taphen-containing complexes is almost the same as (approx. -0.72 V vs. SCE) and much less negative than that of Ru(bpy)/sub 3//sup 2 +/ (-1.35 V). The first oxidation potential increases by 0.11 V as each bpy of Ru(bpy)/sub 3//sup 2 +/ is replaced by taphen. The maximum of the metal-to-ligand charge-transfer (MLCT) absorption band of the taphen-containing complexes lies at slightly higher energy than that of Ru(bpy)/sub 3//sup 2 +/, while the emission maximum lies at lower energy. The lifetime of the emitting excited state is in the 1-..mu..s range at 77 K and in the 0.1-..mu..s range at room temperature, as expected for formally triplet MLCT excited states. Ru(taphen/sub 3//sup 2 +/ does not follow the correlation observed by other RuL/sub 3//sup 2 +/ complexes between energy of the absorption maximum and (E/sub 1/2/(RuL/sub 3//sup 3+/2+/) - E/sub 1/2/(RuL/sub 3//sup 2+/+)), showing that different ..pi..*(taphen) orbitals are involved in the two processes. Examination of the analogous correlation involving the emission maxima shows that the ..pi..*(taphen) orbital involved in reduction is presumably the same as that involved in the luminescence emission. 52 references, 4 figures, 2 tables.

• Research Organization: Istituto Chimico G. Ciamician, Bologna, Italy
• OSTI ID: 5889785
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 25:3; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ABSORPTION SPECTRA
ABSORPTION SPECTROSCOPY
AZINES
BIPYRIDINES
CHELATES
CHEMICAL PREPARATION
COMPLEXES
DATA
EFFICIENCY
ELECTRON TRANSFER
EMISSION SPECTRA
EMISSION SPECTROSCOPY
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
LIFETIME
LIGANDS
LOW TEMPERATURE
LUMINESCENCE
MEDIUM TEMPERATURE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDAZINES
PYRIDINES
QUANTUM EFFICIENCY
REDOX POTENTIAL
RUTHENIUM COMPLEXES
SPECTRA
SPECTROSCOPY
SYNTHESIS
TRANSITION ELEMENT COMPLEXES