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Metal Complexes with Macrocyclic Ligands. Part XXVIII. . Structures and stabilities of the Cu 2+ complexes with 1,4,7‐triazacyclononane‐1‐acetic acid
Author(s) -
Studer Martin,
Riesen Andreas,
Kaden Thomas A.
Publication year - 1989
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19890720215
Subject(s) - chemistry , carboxylate , potentiometric titration , metal , acetic acid , square pyramidal molecular geometry , crystallography , stability constants of complexes , inorganic chemistry , copper , atom (system on chip) , ion , metal ions in aqueous solution , crystal structure , stereochemistry , organic chemistry , computer science , embedded system
The potentiometric study of the complexation of 1,4,7‐triazacyclononane‐l‐acetic acid ( 1 ) with Cu 2+ ( I = 0.5 (KNO 3 ), T = 25°) indicates the presence of the species [Cu( 1 )], [Cu( 1 )OH], [Cu( 1 ) 2 ], and [(Cu( 1 )) 2 OH], the stability constants of which are determined. The two complexes [Cu( 1 )]ClO 4 and [(Cu( 1 ) 2 )OH]ClO 4 were also characterized by X‐ray structure analysis. In both cases, the Cu 2+ ion is in a distorted square‐pyramidal arrangement, penta‐coordinated by the three N‐atoms of the macrocycle, an O‐atom of the carboxylate, and an additional O‐atom either from a second carboxylate or from an OH − , acting as a bridge between two metal centres.