The influence of aryl-bonded substituents upon the complex formation of monobenzocrown ethers towards alkali metal ions in methanol and acetone solutions are investigated by using calorimetric and potentiometric titration. A different complexation behaviour of the ligands in acetone and methanol was found. In the case of the 1:1 complexation of Na+ a correlation between substiuent effects and stability constants in acetone was noticed, however, the influence of substituents upon complex stability is weak. In methanol solutions no similar correlation could be established. During sandwich complexation of K+ in methanol, no significant substituent influences on K-1 and K-2 were observed. On the other hand, a considerable increase of Delta H-2 for both the electron accepting and electron releasing substituents was found, probably caused by changes in ligand-cation solvation due to the substituents.
About the Influence of Some Experimentally Parameters in the Homogeneous Catalyzed Metathesis of Pentene-(2) by WCl 6 -EtAlCl 2 The metathesis of a cis-trans-mixture of pentene-(2) was studied in presence of the catalytic active system WCl 6 –EtAlCl 2 , which was formed in situ. The influence of different solvents and the additiones of Lewis bases was examined. In a further study we established the dependence of the experimentally obtained results on various ratios of compounds in the reaction desposits. In some cases alkylation of aromatic solvents was observed under conditions of olefine metathesis. All reactions were carried out in homogeneous solution.
AbstractDurch kinetische Messungen in Verbindung mit Konkurrenzreaktionen konnte nachgewiesen werden, daß Bischlornitrosoverbindungen, die aus NOCl und Olefinen zugänglich sind, ebenso wie die entsprechenden α‐Chloroxime mit nucleophilen Agenzien nach einem Eliminierungs‐Additions‐Mechanismus reagieren. Die als Zwischenprodukte auftretenden Nitrosoolefine konnten UV‐spektroskopisch nachgewiesen werden. Dimere Nitrosoolefine wurden als definierte Verbindungen aus den NOCl‐Addukten einiger Aryläthylene gewonnen.
