Dual emission from an ortho-metalated Ir(III) complex
Several complexes of Ir(III) containing both the bidentate N-coordinating ligand 2,2'-bipyridine (bpy) and the N,C-orthometalating ligand 2-phenylpyridine (ppy) have recently been prepared; these include the two species Ir(ppy)/sub 2/(bpy)/sup +/ (A) and Ir(ppy)(bpy)/sub 2//sup 2 +/ (B). The former was prepared from the dichloro-bridged dimer, (Ir(ppy)/sub 2/Cl)/sub 2/, by modification of the procedure of Nonoyama while the latter was obtained by reaction of cis-(Ir(bpy)/sub 2/(OSO/sub 2/CF/sub 3/)/sub 2/) (CF/sub 3/SO/sub 3/) with ppy in refluxing 2-ethoxyethanol. The purity of the complexes was monitored with thin-layer chromatography using silica gel plates and 1:1:1 acetone/methanol/water mixtures for elution. Samples of the complexes used in these studies showed only one component in thin-layer chromatography. While only one isomer of B is possible, there are three possible isomers of A. Data from /sup 1/H and /sup 13/C NMR experiments indicate that A has C/sub 2/ symmetry. The NMR spectrum indicates, as does thin-layer chromatography, that only a single isomer of A is present with no detectable impurities due to a mixture of isomers. While X-ray structural data for A are lacking, structural data for related complexes suggest that A is the isomer with cisoid metal-carbon bonds and bpy metal-nitrogen bonds transoid to the metal-carbon bonds and bpy metal-nitrogen bonds transoid to the metal-carbon bonds. These species were prepared in order to probe further the effects of metal-carbon bonding on energy-transfer processes and electron-transfer reactions of metal complexes. Emission spectroscopic studies reported here reveal unusual and distinct intramolecular energy-transfer behavior in these complexes. Whereas dual emission from the former is observed in glasses at 77 K, a single emission is observed in the latter.
- Research Organization:
- Univ. of California, Santa Barbara
- DOE Contract Number:
- AT03-76ER70277
- OSTI ID:
- 6630971
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 109:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AROMATICS
CHEMICAL PREPARATION
EXCITED STATES
BIPYRIDINES
IRIDIUM COMPLEXES
ABSORPTION SPECTROSCOPY
CARBON 13
CHEMICAL BONDS
ELECTRON TRANSFER
EMISSION SPECTROSCOPY
EXPERIMENTAL DATA
HYDROGEN
ISOMERS
LIGANDS
NUCLEAR MAGNETIC RESONANCE
PULSE TECHNIQUES
THIN-LAYER CHROMATOGRAPHY
AZINES
CARBON ISOTOPES
CHROMATOGRAPHY
COMPLEXES
DATA
ELEMENTS
ENERGY LEVELS
EVEN-ODD NUCLEI
HETEROCYCLIC COMPOUNDS
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NONMETALS
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
RESONANCE
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties