Spectroscopic characterization of triple-decker lanthanide porphyrin sandwich complexes. Effects of strong. pi. pi. interactions in extended assemblies
- Carnegie-Mellon Univ., Pittsburgh, PA (USA)
Electrochemical, optical absorption, near-infrared, infrared, resonance Raman, and electron paramagnetic resonance data are reported for several neutral and singly oxidized triple-decker lanthanide porphyrin sandwich complexes Ln{sub 2}(OEP){sub 3} (Ln = La(III), Ce(III), Eu(III); OEP = octaethylporphyrin). The data indicate that there are strong {pi}{pi} interactions between the porphyrin macrocycles in all of the complexes. As a consequence, the hole in the porphyrin {pi} system of the Ln{sub 2}(OEP){sub 3}{sup +} systems is delocalized over all three rings on the vibrational and electronic time scales. The singly oxidized complexes exhibit a characteristic electronic absorption band at very low energies (ca. 2200 nm). This absorption arises as a direct consequence of the strong {pi}{pi} interactions between the rings. A molecular orbital scheme is proposed that accounts for this low-energy feature as well as a number of other properties of the triple-decker sandwich complexes.
- OSTI ID:
- 5290572
- Journal Information:
- Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 112:24; ISSN 0002-7863; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400102* -- Chemical & Spectral Procedures
ABSORPTION SPECTROSCOPY
CARBOXYLIC ACIDS
CERIUM COMPLEXES
CHEMICAL BONDS
COMPLEXES
DATA
ELECTRON SPIN RESONANCE
EUROPIUM COMPLEXES
EXPERIMENTAL DATA
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
LANTHANUM COMPLEXES
LASER SPECTROSCOPY
MAGNETIC RESONANCE
MEASURING METHODS
MOLECULAR ORBITAL METHOD
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PORPHYRINS
RAMAN SPECTROSCOPY
RARE EARTH COMPLEXES
RESONANCE
SPECTROSCOPY