ISSN:
0018-019X
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
12,12-Dimethyl-1,4,7,10-tetraazacyclotridecane (I), 11,13-dimethyl-1,4,7,10-tetraazacyclotridecane (II), 11,11,13-trimethyl-1,4,7,10-tetraazacyclotridecane (III) and 1,4,7,10,12,12-hexamethyl-1,4,7,10-tetraazacyclotridecane (IV) have been synthesized and their properties are described.While the Ni2+ and Cu2+ complexes of I-III have square planar geometries, those of IV are pentacoordinate according to their absorption spectra. Similarly, while the Co2+ complex of I is octahedral and readily oxygenated, the analogous complex with IV is pentacoordinate and not sensitive to oxygen.The rate of complexation of these ligands with Cu2+ and Ni2+ decreases in the order I 〉 II 〉 III ≫ IV, indicating that the number as well as the position of the methyl groups are important. Finally for Cu2+ the formation of the thermodynamic stable end product is slown down by methyl substitution in α-position to the coordinating nitrogen atoms (ligand II and III) so that an intermediate can be observed, whereas with I Cu2+ directly forms the end product.
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/hlca.19750580514
