Temperature dependence of the outer-sphere reorganization energy

Journal Article · Thu Sep 30 04:00:00 EDT 1999 · Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory

DOI:https://doi.org/10.1021/jp991755z· OSTI ID:20001132

Derr, D L; Elliott, C M

The temperature dependence of the intervalence charge transfer transition (IT) has been studied for a mixed-valence dinuclear iron complex. The two halves of this complex consist of trisbipyridineiron moieties that are triply linked with saturated alkyl chains. Because the complex is symmetric, the energy of the IT band is a direct measure of the reorganization energy for electron transfer between the two irons. Moreover, for the specific complex under investigation here, the inner-sphere reorganization energy is essentially zero because of an exact cancellation of sigma- and pi-bonding changes upon changing the oxidation state of each iron. As a consequence, the energy of the IT transition is a direct measure of the outer-sphere (solvent) reorganization energy. The energy of the IT band has been investigated over the temperature range {minus}28 C to 30 C. The derivative of the outer-sphere reorganization energy with respect to temperature found from this study was {minus}3.2 {+-} 0.4 cm{sup {minus}1}K{sup {minus}1}. Theoretical calculations based on the Marcus two spheres in a dielectric continuum model and a molecular based model developed by Matyushov were also carried out for comparison with the experimental results. The continuum model predicts a positive slope for the derivative while the Matyushov model gives a negative slope that differs from that of the experimental data by a factor of {approximately}2 in magnitude.

• Research Organization: Colorado State Univ., Fort Collins, CO (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: FG03-97ER14808
• OSTI ID: 20001132
• Journal Information: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Journal Name: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory Journal Issue: 39 Vol. 103; ISSN 1089-5639; ISSN JPCAFH
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CHEMICAL BONDS
ELECTRON EXCHANGE
IRON COMPLEXES
MATHEMATICAL MODELS
TEMPERATURE DEPENDENCE