ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The two macrocycles 1-(2-aminoethyl)- and 1-[2-(dimethylamino)ethyl]-4, 8, 11-trimethyl-1, 4, 8, 11-tetraazacyclotetradecane, 1 and 2, respectively, and their metal complexes with Co2+, Ni2+ and Cu2+ were prepared. The different spectral properties of the complexes with these two ligands can be rationalized by assuming that, in the case of 1, the amino group of the pendant arm is axially coordinated to the metal ion giving a pentacoordinate structure, whereas the dimethylamino group of 2 cannot bind because of sterical hindrance. This is also corroborated by the observation that the complexes of 2 react with unidentate ligands such as N3- and SCN- to give ternary species MLX+, whereas those of 1 do not. This indicates that the complexes of 1 have no free coordination site, their coordination sphere being completely saturated by the five N-atoms of the macrocycle, whereas the complexes of 2 having a vacant site still can add an unidentate ligand.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19830660719
