Exciplex formation of copper(II) octaethylporphyrin revealed by pulsed x-rays.

Journal Article · Mon Apr 19 04:00:00 EDT 2004 · Chem. Phys.

DOI:https://doi.org/10.1016/j.chemphys.2003.12.004· OSTI ID:961403

Chen, L X; Shaw, G B; Liu, T; Jennings, G; Attenkofer, K

The triplet excited structures of Cu(II) octaethylporphyrin (CuOEP) in toluene and in 1:1 mixture of toluene and tetrahydrofuran (THF) were investigated by time-domain laser pulse pump, X-ray pulse probe X-ray absorption spectroscopy (pump-probe XAS) at room temperature using X-rays from a third generation synchrotron source with 100-ps time resolution. The transient optical absorption measurements indicate a strong solvent dependency of the triplet excited state lifetime due to the presence of oxygen-containing solvent molecules. While the ground state CuOEP molecules remain square-planar in both solvents, the attenuation of a peak attributed to the 1s {yields} 4p{sub z} transition at the Cu K-edge for the laser excited CuOEP in the THF/toluene mixture revealed the penta-coordinated exciplex formation which is responsible for the shortening of the triplet excited state lifetime. Meanwhile, the average Cu-N distance in the triplet excited state is lengthened by 0.03 {angstrom} due to ligation with a THF solvent molecule, which agrees with a domed coordination structure for copper in the penta-coordinated exciplex.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 961403
• Report Number(s): ANL/CHM/JA-47441
• Journal Information: Chem. Phys., Journal Name: Chem. Phys. Journal Issue: 2-3, Spec. Suppl. ; Apr. 19, 2004 Vol. 299; ISSN CMPHC2; ISSN 0301-0104
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

43 PARTICLE ACCELERATORS
ABSORPTION
ABSORPTION SPECTROSCOPY
ATTENUATION
COPPER
EXCITED STATES
GROUND STATES
LASERS
MIXTURES
MOLECULES
PULSES
SOLVENTS
TETRAHYDROFURAN
TOLUENE
TRIPLETS