We have located links that may give you full text access.
Experimental studies of light-induced charge transfer and charge redistribution in (X(2)-bipyridine)Re(I)(CO)(3)Cl complexes.
Inorganic Chemistry 2002 June 4
Stark emission spectroscopy, transient DC photoconductivity (TDCP), and ground-state dipole moment measurements have been used to evaluate charge transfer (CT) within various (X(2)-bipyridine)Re(I)(CO)(3)Cl complexes following (3)MLCT excited-state formation. The Stark technique reports on vector differences between ground-state (mu(g)) and excited-state (mu(e)) dipole moments, while TDCP, when combined with independently obtained mu(g) information, reports on scalar differences. For systems featuring collinear, same-signed ground- and excited-state dipole moments, the scalar and vector differences are equivalent. However, for the low symmetry systems studied here, they are distinctly different. The vector difference yields the effective adiabatic one-electron-transfer distance (R(12)), while the combined vector and scalar data yield information about dipole rotation upon ground-state/excited-state interconversion. For the systems examined, charge transfer distances are substantially smaller than geometric electron-donor/electron-acceptor site separation distances. The measured distances are significantly affected by changes in acceptor ligand substituent composition. Electron-donating substituents decrease CT distances, while electron-withdrawing substituents increase CT distances, as do aromatic substituents that are capable of expanding the bipyridyl ligand (acceptor ligand) pi system. The Stark measurements additionally indicate that the CT vector and the transition dipole moment are significantly orthogonal, a consequence of strong polarization of the Re-Cl bond (orthogonal to the metal/acceptor-ligand plane) in the ground electronic state and relaxation of the polarization in the upper state. The ground-state Re-Cl bond polarization is sufficiently large that the overall ground-state scalar dipole moment exceeds the overall excited-state scalar dipole moment, despite transfer of an electron from the metal center to the diimine ligand. This finding provides an explanation for the otherwise puzzling negative solvatochromism exhibited in this family of compounds. Combining TDCP and Stark results, we find that the dipole moment can be rotated in some instances by more than 90 degrees upon (3)MLCT excited-state formation. The degree of rotation or reorientation can be modulated by changing the identity of the acceptor ligand substituents. Reorientational effects are smallest when the compounds feature aromatic substituents capable of spatially extending the pi system of the acceptor ligand.
Full text links
Trending Papers
A Personalized Approach to the Management of Congestion in Acute Heart Failure.Heart International 2023
Potential Mechanisms of the Protective Effects of the Cardiometabolic Drugs Type-2 Sodium-Glucose Transporter Inhibitors and Glucagon-like Peptide-1 Receptor Agonists in Heart Failure.International Journal of Molecular Sciences 2024 Februrary 21
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app