Charge Transfer emission

Bhattacharyya K, Chowdhury M (1993) Environmental and magnetic field effects on exciplex and twisted charge transfer emission. Chem Rev 93 507-535... 

More recently, charge-transfer emission was anticipated when solutions of hydrocarbon anion radical salts in dimethoxyethane were mixed with Wurster s blue perchlorate.15 Emission was seen in every instance however, with eight anion radicals derived from 3 to 5 ring-fused aromatic hydrocarbons, the emission was derived from the hydrocarbon rather than the complex. Preliminary studies with smaller hydrocarbons, biphenyl and naphthalene, did show emission in the region (18 kK) where charge transfer was expected. The question as to what pairs of ion radicals will be emissive under what conditions has only begun to be considered. Much opportunity for further experimentation exists in this area. 

The German collaboration between Berlin and Regensburg has produced an excellent signaling system for Hg2+ and Ag+ [117]. The selectivity of 57 towards Hg2+ and Ag+ (and to a lesser extent, Cu2+) is arranged with the sulfur-rich thiaazacrown receptor. In the present case, as with several other related cases, a weak charge-transfer emission [116] can be observed. But the... 

Fig. 9.36 Representation of the charge-transfer emission intensity (black) versus the C60 fluorescence quantum yield (red) in toluene solutions of 17b...

Soon afterwards, Verhoewen in Amsterdam, The Netherlands, demonstrated the switching capabilities of (7) [13] - the beginnings of the possibilities in the molecular electronics area. Selective protonation neutralized a charge transfer emission process originating from an aliphatic amine and also involving a remote aromatic amine. The switching of optically observable phenomena involving several different molecular sites by means of an externally controllable ionic input was a special novelty of this work. 

The UV absorption and fluorescence properties of 9-(9 -acridyl)carbazole have been investigated in 50 different solvents, and only representative examples are reported <1998EJ01697>. The carbazole unit serves as an electron donor and analysis of the solvatochromic behavior revealed that twisted intramolecular charge transfer emission prevails only in more polar solvents. 

The energies of charge-transfer emission bands can be treated very similarly to the absorptions, as described in Eqs. 6-8 this is done by merely replacing the reorga-nizational terms by their negatives = eg°° - However, the substitution of electrode potentials for will also require a T sS correction if there is... 

Fluorescence spectra of the dyads 23( i) revealed the presence of discrete charge transfer emission bands for bridge lengths up to 10 sigma bonds [75]. These bands... 

Fig. S. Radiative transition in the inverted Marcus region charge-transfer absorption (arrow up) and charge-transfer emission (arrow down).

Unlike the kinetic data for nonradiative electron transfer, analysis of the charge-transfer emission and/or absorption bands makes it possible to determine the quantities Ao, Aj, etc. It can be done by fitting the emission and/or absorption spectra... 

In the case of charge-transfer emission (formally a bimolecular reation), Feldberg plots are also linear (e.g., [118]). The charge-transfer character of this emission, however, can be demonstrated by a correlation of emission energies of various ECL systems with the standard redox potential (e.g., correlation of the emission maxima with the oxidation potentials of the donor or with the reduction potentials of the acceptors [119]). The associated charge-transfer character can also be demonstrated by the effects of solvent and temperature on the emission energy and intensity (e.g., [120]). 

It was described earlier [6] that this class of probes is able to show dual fluorescence. This means that two bands exist in the fluorescence spectrum and the long wavelength band is caused by a charge transfer emission. The position of the band is strongly dependent on the microscopic polarity around the probe. Furthermore, the ratio of the two fluorescence bands depends on the mobility of the probe in the material investigated. These both values are therefore a quantity for the examination of the fluorescence behavior of I. 

Krasnopolsky VA, Mumma MJ (2001) Spectroscopy of comet Hyakutake at 80-700 A First detection of solar wind charge-transfer emissions. Astrophys J 549 629-634 Krasnopolsky VA, Bowyer S, Chakrabarti S, Gladstone GR, McDonald JS (1994) First measurement of helium on Mars implications for the problem of radiogenic gases on the terrestrial planets, learns 109 337-351... 

Kamioka, K., Cormier, R. A., Lutton, T. W., Coimolly, J. S. (1992). Charge-transfer emission in meso-linked zinc porphyrin-anthraquinone molecules, J. Am. Chem. Soc., 114 4414. 

Charge Transfer Emission in Transition Metai Compiexes, Chains, and Layers... 

In addition to intracenter d d emission, transition metal systems frequently exhibit charge transfer emission between metal centered and ligand centered orbitals. The molecular nature of isolated complexes leads to high compressibility and large pressure-induced changes in interatomic separations both within a... 

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