Untersuchungen zur Charge‐Transfer‐Wechselwirkung von Phenolen mit Tetracyanethylen (TCNE)

Abstract

Investigations on the Charge-Transfer Interaction of Phenols with Tetracyanoethylene (TCNE)The donor properties of some phenol derivatives were determined by measuring the UV/Vis spectra of their CT complexes with tetracyanoethylene in 1,2-dichloroethane and acetonitrile at room temperature. The ionization potentials of the phenolic compounds have been calculated by using the longest visible charge-transfer absorption of the donor-acceptor complex by linear correlation analysis. The charge-transfer spectra are discussed in dependence on the ring substituents in terms of electronic and steric factors. Increasing donor strength of the substituents decreases the ionization potential of the phenols as demonstrated by an LFE relationship using the Hammett constants. However, orfho donor substituents enhance the donor strength of the aromatic ring as well.

Solvent polarity scales: determination of new ET(30) values for 84 organic solvents

“…Therefore, in the following, we only comment on the two most important differences, namely 3-methylphenol and HFIP. The literature value [23] of 3-methylphenol is low (52.4) compared to the value of 56.2 measured in this work. The difference comes from the measurement of the former value on 3methylphenol as solute in 1,2-dichloroethane, [23] whereas the latter value has been measured on 3-methylphenol as bulk solvent.…”

“…The literature value [23] of 3-methylphenol is low (52.4) compared to the value of 56.2 measured in this work. The difference comes from the measurement of the former value on 3methylphenol as solute in 1,2-dichloroethane, [23] whereas the latter value has been measured on 3-methylphenol as bulk solvent. The latter method must be preferred since the overall solvation capability of neat 3-methylphenol is here measured.…”

Effect of the Excitation Wavelength on the Ultrafast Charge Recombination Dynamics of Donor−Acceptor Complexes in Polar Solvents

“…This effect is well documented and has been ascribed to the formation of the tricyanoethanolate anion. [49][50][51] Figure 6B shows the time profile of the TA at 400 nm measured with TMB/TCNE in ACN with two different pump wavelengths, which coincide predominantly with the CT1 transition. After 620 nm excitation, the whole signal decays to zero within the response function of the instrument.…”

Kinetics and Mechanism of Photodegradation of Chlorophenols

“…It is considered that singlet oxygen undergoes five distinctive types of reaction [112]: (i) ene-reaction with many alkenes to give allylic hydroperoxides (50) (ii) (2 + 4) cycloaddition to dienes (51) (iii) (2 + 2) cycloaddition to electron-rich alkenes (52) (iv) oxidation of sulfur in sulfides, disulfides and mercaptans…”