Zum Einflu� von arylst�ndigen Substituenten auf die Komplexbildung von Monobenzokronenethern mit Alkalimetallionen in Methanol und Aceton

Autor: Hans-Jürgen Buschmann, Jörg Beger, Rainer Trültzsch, Gert Wolf
Rok vydání: 1994
Předmět:
Zdroj: Journal f�r Praktische Chemie/Chemiker-Zeitung. 336:5-10
ISSN: 1521-3897
0941-1216
Popis: Influence of Aryl-bonded Substituents on Complex Formation of Benzocrown Ethers with Alkali Metal Ions in Methanol and Acetone Solutions 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 K1 and K2 were observed. On the other hand, a considerable increase of ΔH2 for both the electron accepting and electron releasing substituents was found, probably caused by changes in ligand-cation solvation due to the substituents.
Databáze: OpenAIRE
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