N. Charton,A. Feldermann,A. Theis,M. H. Stenzel,T. P. Davis,C. Barner‐Kowollik,Initiator efficiency of 2,2′‐azobis(isobutyronitrile) in bulk dodecyl acrylate free‐radical polymerizations over a wide conversion and molecular weight range (2004) 42(20) 5170–5179

The original article to which this Erratum refers was published in J Polym Sci Part A: Polym Chem (2004) 42(20) 5170–5179. No abstract.     

Calculation of the frequencies and intensities in the infrared and raman spectra of cyclopropenone

By using the values of the vibrational frequencies of normal and deuterated cyclopropenone (II-d₀ , II-d₂ ) and ¹⁶ O-and ¹⁸ O-substituted dimethylcyclopropenone (III) as -well as the infrared and Raman intensities of II a consistent set of force constants has been derived for the cyclopropenone skeleton. The derived values show that the zwitterionic form makes a substantial contribution to the electronic ground state of the molecule. The combined frequency and intensity calculation - simulation of the infrared and the Raman spectrum - is shown to be a good method for making a proper assignment of calculated and observed vibrations and deriving realistic sets of force constants.     

On the reaction of 4-substituted trimethyltin aromatics with perchlorylfluoride

To evaluate the suitability of [¹⁸F]perchorylfluoride [¹⁸F]FClO₃ as an electrophilic fluorination agent for the preparation of radiopharmaceuticals, the reactivity non-radioactive FClO₃ towards 4-substituted trimethyltin aromatic compounds was studied. Contrary to the expectation, an electrophilic fluorination of the aromatic nucleus did not occur. The reaction of perchlorylfluoride with aromatic trimethylstannyl compounds resulted in the formation of trimethyltin fluoride and the respective destannylated aromatics in variable yields.     

Hemicucurbit[6]uril a Macrocyclic Ligand with Unusual Complexing Properties

The complex formation of the macrocyclic ligand hemicucurbit[6]uril with various salts has been studied in aqueous solution. Due to the low solubility of this ligand the formation of complexes results in an increase of the amount of ligand present in solution. From these measurements the stability constants of the complexes formed are calculated. Hemicucurbit[6]uril only forms cation complexes with cobalt(II), nickel(II) and the uranylion. All other cations examined e.g. silver(I), lead(II) and copper(II) do not form detectable complexes in aqueous solution. For a better understanding of the complexation behaviour some quantum mechanical chemical calculations are performed with Gaussian.Dedicated to Prof. H. Möhwald on the occasion of his 60th birthday.     

Quantitative determination of chloride by means of flow injection analysis with spectrophotometric detection in the UV/VIS range

Chloride is determined indirectly by Spectrophotometric flow injection analysis. Two systems are compared, both based on the principle of ion exchange of easily detectable anions versus chloride from suitable mercury salts. The first method is based on the exchange of chloride with chloranilate which is detected at 332 nm or at 306 nm in neutral or in acidic medium respectively. In the second case, chloride reacts with Hg(SCN)₂. The liberated thiocyanate forms a strongly coloured complex with Fe(III) in acidic solution with an absorption maximum at 460 nm. Both methods have a detection limit of about 5 mol Cl^–/l (175 ng/ml). In the case of the thiocyanate method, the relative standard deviation is about 2% (7 measurements) in the range of 5 to 150 mol/l and decreases significantly to a value of approximately 0.2% at higher concentrations; for the chloranilate method it is 10% for lower and about 1% for higher concentrations respectively.