10.1021/jp8107705.s001
Daniel R. Kattnig
Daniel R.
Kattnig
Boryana Mladenova
Boryana
Mladenova
Günter Grampp
Günter
Grampp
Conrad Kaiser
Conrad
Kaiser
Alexander Heckmann
Alexander
Heckmann
Christoph Lambert
Christoph
Lambert
Electron Paramagnetic Resonance Spectroscopy of Bis(triarylamine) Paracyclophanes as Model Compounds for the Intermolecular Charge-Transfer in Solid State Materials for Optoelectronic Applications
American Chemical Society
2009
EPR
Paracyclophane
magnitude
van der Waals radii
Solid State Materials
method
barrier
electron transfer rate constants
cation
state materials triarylamines
paracyclophane
electron Paramagnetic Resonance Spectroscopy
1 order
2009-02-19 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Electron_Paramagnetic_Resonance_Spectroscopy_of_Bis_triarylamine_Paracyclophanes_as_Model_Compounds_for_the_Intermolecular_Charge_Transfer_in_Solid_State_Materials_for_Optoelectronic_Applications/2877244
A set of seven bis(triarylamine) mixed-valence radical cations with different bridging moieties were investigated by temperature-dependent electron paramagnetic resonance (EPR) spectroscopy in methylene chloride and <i>ortho</i>-dichlorobenzene to evaluate the thermal electron transfer rate constants. The bridges used comprise [2,2]paracyclophane and [3,3]paracyclophane as well as fully conjugated phenylene spacers. The cyclophanes serve as model structures for studying the intermolecular electron transfer in solid state materials. The activation barriers derived by EPR measurements are compared with those estimated by the two-state Marcus−Hush analysis as well as by its extension to three states. Both methods gave good agreement with the EPR data, the three-state method being slightly better than the two-state method. On the basis of the choice of the different bridging groups, our study shows that the bridge can have a significant influence on the internal reorganization energy. [2,2]Paracyclophane and [3,3]paracyclophane bridge units show practically the same electronic coupling and thermal barrier. Conjugated bridges have thermal rates about 1 order of magnitude larger than the radical cations with broken conjugation. These two aspects show that in solid state materials triarylamines drawn close to their van der Waals radii may exhibit efficient coupling and rate constants by only 1 order of magnitude smaller than fully conjugated materials.