Adiabatic electron transfer: comparison of modified theory with experiment

Area of Science:

• Chemical kinetics
• Spectroscopy
• Electron transfer mechanisms

Background:

• Bishydrazines serve as model compounds for studying electron transfer.
• Radical cations of bishydrazines exhibit measurable electron transfer rate constants.
• Charge transfer bands provide insights into electronic transitions.

Purpose of the Study:

• To compare observed and calculated electron transfer rate constants for bishydrazine radical cations.
• To investigate the relationship between charge transfer bands and electron transfer dynamics.
• To determine if tunneling corrections are necessary for these systems.

Main Methods:

• Synthesis and characterization of six bishydrazine compounds.
• Measurement of electron transfer rate constants using dynamic electron spin resonance spectroscopy.
• Analysis of charge transfer bands to determine adiabatic surface shapes.

Main Results:

• Electron transfer rate constants were small enough for dynamic electron spin resonance spectroscopy.
• Charge transfer bands corresponded to vertical excitations in the electron-transferring species.
• Adiabatic surface shapes derived from charge transfer bands accurately predicted electron transfer rate constants.

Conclusions:

• The shape of the adiabatic surface is accurately obtainable from charge transfer bands.
• Accurate prediction of electron transfer rate constants is possible without explicit tunneling corrections for these compounds.
• Bishydrazine radical cations are suitable models for fundamental electron transfer studies.