Relativistic effects in general lead to a radial contraction of the s and p orbitals and to an expansion of the d this is particularly true in the case of Hf because of the increase of relativistic effects with Z2.[351 The result is a volume contraction of the Hf phosphide because of its smaller, st
Photoinduced Electron and Energy Transfer in Dyads of Porphyrin Dimer and Perylene Tetracarboxylic Diimide
β Scribed by Wei Xu; Hailong Chen; Yanfeng Wang; Chuntao Zhao; Xiyou Li; Shuangqing Wang; Yuxiang Weng
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 286 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1439-4235
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β¦ Synopsis
Abstract
Two compounds containing a porphyrin dimer and a perylene tetracarboxylic diimide (PDI) linked by phenyl (1) or ethylene groups (2) are prepared. The photophysical properties of these two compounds are investigated by steady state electronic absorption and fluorescence spectra and lifetime measurements. The ground state absorption spectra reveal intense interactions between the porphyrin units within the porphyrin dimer, but no interactions between the porphyirn dimer and PDI. The fluorescence spectra suggest efficient energy transfer from PDI to porphyrin accompanied by less efficient electron transfer from porphyrin to PDI. The energy transfer is not affected by the dimeric structure of porphyrin or the linkage between the porphyrin dimer and PDI. However, the electron transfer from porphyrin to PDI is significantly affected by either the linkage between the donor and the acceptor or the polarity of the solvents. The dimeric structure of the porphyrin units in these compounds significantly promotes electron transfer in nonpolar, but not in polar solvents.
π SIMILAR VOLUMES
Laser-flash-photolysis experiments show that, in MeCN at 20". perylene (P) undergoes three distinct electrontransfer reactions: a) IP\* + MeCN 4 P'+ + MeCN'b) ' P \* t P 4 P ' + + P ' c) 3P\* + 3P\* 4 (P.P)\* ~ P" + P' These processes originate probably from the thermally relaxed excited states of P