Abstract
The title cyclophanes are dimers of methyl mesopyropheophorbide a that are connected by two covalent linkages. Insertion of zero, one, or two magnesium ions in the cyclophane provides a series of compounds that are useful in exploring artificial photosynthesis. In contrast to recently studied cofacial proporphyrins, the macrocycles of these dimers have orthogonal transition moments. This precludes strong interaction in spite of their close distance. The ground-state absorbance and emission spectra of the dimetalated and nometalated cyclophanes are similar to those of the corresponding monomers but show small red shifts, broadening, and hypochromism of the lowest energy ( pi yields pi *) transition. Difference spectra for absorbance of the excited state are presented for the monomers and the monometalated cyclophane. A weak vibronic coupling mechanism is proposed to account for the absorbance band broadening and is indicated by the circular dichroism observed.
| Original language | English |
|---|---|
| Pages (from-to) | 4256-4260 |
| Number of pages | 5 |
| Journal | Journal of the American Chemical Society |
| Volume | 105 |
| Issue number | 13 |
| Publication status | Published - Jan 1 1983 |
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ASJC Scopus subject areas
- Chemistry(all)
Cite this
PHOTOPHYSICS OF BIS(CHLOROPHYLL)CYCLOPHANES : MODELS OF PHOTOSYNTHETIC REACTION CENTERS. / Overfield, Robert E.; Scherz, Avigdor; Kaufmann, Kenneth J.; Wasielewski, Michael R.
In: Journal of the American Chemical Society, Vol. 105, No. 13, 01.01.1983, p. 4256-4260.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - PHOTOPHYSICS OF BIS(CHLOROPHYLL)CYCLOPHANES
T2 - MODELS OF PHOTOSYNTHETIC REACTION CENTERS.
AU - Overfield, Robert E.
AU - Scherz, Avigdor
AU - Kaufmann, Kenneth J.
AU - Wasielewski, Michael R
PY - 1983/1/1
Y1 - 1983/1/1
N2 - The title cyclophanes are dimers of methyl mesopyropheophorbide a that are connected by two covalent linkages. Insertion of zero, one, or two magnesium ions in the cyclophane provides a series of compounds that are useful in exploring artificial photosynthesis. In contrast to recently studied cofacial proporphyrins, the macrocycles of these dimers have orthogonal transition moments. This precludes strong interaction in spite of their close distance. The ground-state absorbance and emission spectra of the dimetalated and nometalated cyclophanes are similar to those of the corresponding monomers but show small red shifts, broadening, and hypochromism of the lowest energy ( pi yields pi *) transition. Difference spectra for absorbance of the excited state are presented for the monomers and the monometalated cyclophane. A weak vibronic coupling mechanism is proposed to account for the absorbance band broadening and is indicated by the circular dichroism observed.
AB - The title cyclophanes are dimers of methyl mesopyropheophorbide a that are connected by two covalent linkages. Insertion of zero, one, or two magnesium ions in the cyclophane provides a series of compounds that are useful in exploring artificial photosynthesis. In contrast to recently studied cofacial proporphyrins, the macrocycles of these dimers have orthogonal transition moments. This precludes strong interaction in spite of their close distance. The ground-state absorbance and emission spectra of the dimetalated and nometalated cyclophanes are similar to those of the corresponding monomers but show small red shifts, broadening, and hypochromism of the lowest energy ( pi yields pi *) transition. Difference spectra for absorbance of the excited state are presented for the monomers and the monometalated cyclophane. A weak vibronic coupling mechanism is proposed to account for the absorbance band broadening and is indicated by the circular dichroism observed.
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UR - http://www.scopus.com/inward/citedby.url?scp=0020765377&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0020765377
VL - 105
SP - 4256
EP - 4260
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 13
ER -