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Copper(II) and Nickel(II) Complexes of ` trans '‐Difunctionalized Tetraaza Macrocycles
Author(s) -
Comparone Antonio,
Kaden Thomas A.
Publication year - 1998
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/(sici)1522-2675(19981007)81:10<1765::aid-hlca1765>3.0.co;2-n
Subject(s) - chemistry , hexacoordinate , protonation , octahedron , hydrolysis , nickel , aminal , stereochemistry , medicinal chemistry , polymer chemistry , crystal structure , crystallography , organic chemistry , ion , silicon
Reductive cleavage of the bis‐aminal 1 of 1,4,8,11‐tetraazacyclotetradecane allows a new synthesis of 1,8‐dimethyl‐1,4,8,11‐tetraazacyclotetradecane ( 3 ), which is an ideal starting compound for preparing ` trans '‐difunctionalized derivatives. Thus, 3 was reacted to give the macrocyclic diacetonitrile 5 and dipropanenitrile 9 . These were reduced with Raney ‐Ni and H 2 to the corresponding diamines 6 and 10 , respectively. In addition, 5 was selectively hydrolysed to the diacetamide 7 and fully hydrolysed to the diacetic acid 8 . The Cu 2+ and Ni 2+ complexes of these new ligands were prepared and their spectral and structural properties studied. Whereas 3 yielded square planar species, the functionalized derivatives gave penta‐ or hexacoordinate complexes. The ligands with amino groups in their side chains ( 6 and 10 ) formed square planar species at acidic pH (amino groups protonated), but pentacoordinate geometries resulted at alkaline pH, where one amino group underwent coordination. In contrast, the diacetic acid 8 gave distorted octahedral Cu 2+ and Ni 2+ complexes.