Dyads and Triads Containing Perylenetetracarboxylic Diimide and Porphyrin:  Efficient Photoinduced Electron Transfer Elicited via Both Excited Singlet States

2005 ◽  
Vol 109 (8) ◽  
pp. 3658-3667 ◽  
Author(s):  
Shengqiang Xiao ◽  
Mohamed E. El-Khouly ◽  
Yuliang Li ◽  
Zhenhai Gan ◽  
Huibiao Liu ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Excited Singlet ◽  
Singlet States ◽  
Excited Singlet States

scholarly journals The Ugi four-component reaction as a concise modular synthetic tool for photo-induced electron transfer donor-anthraquinone dyads

2014 ◽  
Vol 10 ◽  
pp. 1006-1016 ◽  
Author(s):  
Sarah Bay ◽  
Gamall Makhloufi ◽  
Christoph Janiak ◽  
Thomas J J Müller
Keyword(s):  
Electron Transfer ◽  
Excited Singlet ◽  
Gibbs Energies ◽  
Singlet States ◽  
Vis Spectroscopy ◽  
Donor Acceptor ◽  
Photo Induced Electron Transfer ◽  
Excited Singlet States ◽  
A Charge ◽  
Electronic Ground

Phenothiazinyl and carbazolyl-donor moieties can be covalently coupled to an anthraquinone acceptor unit through an Ugi four-component reaction in a rapid, highly convergent fashion and with moderate to good yields. These novel donor–acceptor dyads are electronically decoupled in the electronic ground state according to UV–vis spectroscopy and cyclic voltammetry. However, in the excited state the inherent donor luminescence is efficiently quenched. Previously performed femtosecond spectroscopic measurements account for a rapid exergonic depopulation of the excited singlet states into a charge-separated state. Calculations of the Gibbs energy of photo-induced electron transfer from readily available UV–vis spectroscopic and cyclovoltammetric data applying the Weller approximation enables a quick evaluation of these novel donor–acceptor dyads. In addition, the X-ray structure of a phenothiazinyl–anthraquinone dyad supports short donor–acceptor distances by an intramolecular π-stacking conformation, an important assumption also implied in the calculations of the Gibbs energies according to the Weller approximation.

Quasiparticle Excitations in Polyenes and Polyacetylene

1987 ◽  
Vol 109 ◽  
Author(s):  
Paul Tavan ◽  
Klaus Schulten
Keyword(s):  
Dispersion Relations ◽  
Excited Singlet ◽  
Quasi Particle ◽  
Double Excitation ◽  
Singlet States ◽  
Excited Singlet States ◽  
Electron Excitations ◽  
Quasiparticle Excitations

ABSTRACTWe apply the Pariser-Parr-Pople Hamiltonian to study many-electron excitations in polyenes and polyacetylene. The excited singlet states of polyenes, calculated by a multireference double excitation expansion, are classified as quasi-particle excitations, namely as triplet-triplet magnons and particle-hole excitons. From finite polyene spectra we derive approximate dispersion relations for these quasi-particles in the infinite polyene, i.e. polyacetylene.

Sign in / Sign up

Export Citation Format

Share Document