A General Iron-Catalyzed Decarboxylative Oxygenation of Aliphatic Carboxylic Acids.

We report an iron-catalyzed decarboxylative C(sp)-O bond-forming reaction under mild, base-free conditions with visible light irradiation. The transformation uses readily available and structurally diverse carboxylic acids, iron photocatalyst, and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) derivatives as oxygenation reagents. The process exhibits a broad scope in acids possessing a wide range of stereoelectronic properties and functional groups.

Efficient Prediction of Mole Fraction Related Vibrational Frequency Shifts.

While so far it has been possible to calculate vibrational spectra of mixtures at a particular composition, we present here a novel cluster approach for a fast and robust calculation of mole fraction dependent infrared and vibrational circular dichroism spectra at the example of acetonitrile/()-butan-2-ol mixtures. By assigning weights to a limited number of quantum chemically calculated clusters, vibrational spectra can be obtained at any desired composition by a weighted average of the single cluster spectra. In this way, peak positions carrying information about intermolecular interactions can be predicted.

Time-resolved Fourier-transform infrared spectroscopy reveals the hidden bimolecular process of the ferrioxalate actinometer.

Step-scan Fourier-transform infrared spectroscopy was used to monitor the photochemical reactions following the 266 nm-photolysis of aqueous ferrioxalate solutions on microsecond-to-millisecond time scales. Together with most recent observations from ultrafast infrared spectroscopy the reported results finally disclose the full molecular-level mechanism of a photochemical system that is widely known as the Hatchard-Parker actinometer.