Abstract
The pressure dependence of the two intervalence transfer (IT) electronic absorption bands of the mixed-valence bis(fulvalene)diiron cation is examined in various media. In general, a blue shift with increasing pressure is seen for both IT bands in all media. The blue shifting is attributable to an intramolecular effect, where an increase in pressure leads to an increase in the energy separation between the bonding ground and antibonding excited states of the IT transition. At high pressures and to variable degrees in the different media (crystal lattice, PMMA polymer, intercalated into zeolite 13X) compression leads to intermolecular effects on the energy of the two IT bands. Data obtained for the zeolite-intercalated bis(fulvalene)diiron cation are analyzed in terms of the PKS vibronic model. Values for the electronic and vibronic coupling parameters are obtained from spectra measured in the range of 11–138 kbar. The value of the PKS electronic coupling factor e was shown to increase by a factor of ~ 1.5 over this pressure range. The degree of valence localization in the bis(fulvalene)diiron cation can be changed appreciably with pressure. From and the PKS vibronic coupling factor X evaluated for the low-energy IT band it was calculated that| e|/X2, a ratio that characterizes the valence localization, increases continuously from 0.59 at 11 kbar to 0.78 at 89 kbar.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7340-7345 |
| Number of pages | 6 |
| Journal | Journal of the American Chemical Society |
| Volume | 109 |
| Issue number | 24 |
| DOIs | |
| State | Published - Nov 1 1987 |
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ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Pressure Effects on the Intervalence Transfer Electronic Absorption Band of the Mixed-Valence Bis(fulvalene)diiron Monocation in Various Media. / Sinha, Usha; Lowery, Michael D.; Hammack, William S; Hendrickson, David N.; Drickamer, Harry G.
In: Journal of the American Chemical Society, Vol. 109, No. 24, 01.11.1987, p. 7340-7345.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pressure Effects on the Intervalence Transfer Electronic Absorption Band of the Mixed-Valence Bis(fulvalene)diiron Monocation in Various Media
AU - Sinha, Usha
AU - Lowery, Michael D.
AU - Hammack, William S
AU - Hendrickson, David N.
AU - Drickamer, Harry G.
PY - 1987/11/1
Y1 - 1987/11/1
N2 - The pressure dependence of the two intervalence transfer (IT) electronic absorption bands of the mixed-valence bis(fulvalene)diiron cation is examined in various media. In general, a blue shift with increasing pressure is seen for both IT bands in all media. The blue shifting is attributable to an intramolecular effect, where an increase in pressure leads to an increase in the energy separation between the bonding ground and antibonding excited states of the IT transition. At high pressures and to variable degrees in the different media (crystal lattice, PMMA polymer, intercalated into zeolite 13X) compression leads to intermolecular effects on the energy of the two IT bands. Data obtained for the zeolite-intercalated bis(fulvalene)diiron cation are analyzed in terms of the PKS vibronic model. Values for the electronic and vibronic coupling parameters are obtained from spectra measured in the range of 11–138 kbar. The value of the PKS electronic coupling factor e was shown to increase by a factor of ~ 1.5 over this pressure range. The degree of valence localization in the bis(fulvalene)diiron cation can be changed appreciably with pressure. From and the PKS vibronic coupling factor X evaluated for the low-energy IT band it was calculated that| e|/X2, a ratio that characterizes the valence localization, increases continuously from 0.59 at 11 kbar to 0.78 at 89 kbar.
AB - The pressure dependence of the two intervalence transfer (IT) electronic absorption bands of the mixed-valence bis(fulvalene)diiron cation is examined in various media. In general, a blue shift with increasing pressure is seen for both IT bands in all media. The blue shifting is attributable to an intramolecular effect, where an increase in pressure leads to an increase in the energy separation between the bonding ground and antibonding excited states of the IT transition. At high pressures and to variable degrees in the different media (crystal lattice, PMMA polymer, intercalated into zeolite 13X) compression leads to intermolecular effects on the energy of the two IT bands. Data obtained for the zeolite-intercalated bis(fulvalene)diiron cation are analyzed in terms of the PKS vibronic model. Values for the electronic and vibronic coupling parameters are obtained from spectra measured in the range of 11–138 kbar. The value of the PKS electronic coupling factor e was shown to increase by a factor of ~ 1.5 over this pressure range. The degree of valence localization in the bis(fulvalene)diiron cation can be changed appreciably with pressure. From and the PKS vibronic coupling factor X evaluated for the low-energy IT band it was calculated that| e|/X2, a ratio that characterizes the valence localization, increases continuously from 0.59 at 11 kbar to 0.78 at 89 kbar.
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U2 - 10.1021/ja00258a017
DO - 10.1021/ja00258a017
M3 - Article
AN - SCOPUS:0008087014
VL - 109
SP - 7340
EP - 7345
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 24
ER -