Electronic spectra of pyrazolyl-bridged binuclear iridium(I) complexes

Journal Article · Wed Nov 25 04:00:00 EST 1992 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00050a022· OSTI ID:6900247

Marshall, J L; Hopkins, M D; Miskowski, V M; Gray, H B ^[1]

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1. California Inst. of Technology, Pasadena (United States)

The electronic absorption and emission spectra and emission lifetimes of Ir[sub 2]([mu]-L)[sub 2](CO)[sub 4] (L = pyrazolyl, 3-methylpyrazolyl, 3,5-dimethylpyrazolyl) have been determined in the temperature range 77-300 K. Polarized emission excitation spectra of the complexes in rigid glassy solutions at 77 K are also reported. Like face-to-face d[sup 8]-d[sup 8] systems, these A-frame complexes display dipole-allowed transitions to emissive singlet and triplet excited states derived from monomer d[sub z[sup 2]] [yields] p[sub z] excitations; these dimer excited states are stabilized relative to monomer excited states by strong metal-metal bonding. There is a second singlet/triplet pair of excited states, also derived from monomer d[sub z[sup 2]] [yields] p[sub z] excitations; although transitions to these states are dipole forbidden in face-to-face structures, the corresponding bands in the absorption spectra of the A-frame complexes possess considerable intensity. These latter excited states have negligible metal-metal bonding stabilization relative to the monomer states, but considerable metal-ligand charge-transfer character, as judged by well-resolved [nu](Ir-CO) vibronic structure in the absorption bands. Overall, the spectroscopic results are consistent with a valence-bond model for the Ir-Ir interaction.

• OSTI ID: 6900247
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 31:24; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ABSORPTION SPECTROSCOPY
AZOLES
CARBONYLS
COMPLEXES
DATA
ELECTRONIC STRUCTURE
EMISSION SPECTROSCOPY
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
IRIDIUM COMPLEXES
LIFETIME
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRAZOLES
SPECTROSCOPY
TEMPERATURE EFFECTS
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TRANSITION ELEMENT COMPLEXES