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Highly Substituted Cyclams: Stereoselective Synthesis and Coordination Properties
Author(s) -
König Burkhard,
Pelka Mario,
Möller Oliver,
Dix Ina,
Jones Peter G.
Publication year - 1997
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19971300412
Subject(s) - chemistry , cyclam , stereoselectivity , ligand (biochemistry) , nickel , acetylacetone , zinc , methanol , medicinal chemistry , macrocyclic ligand , copper , metal , stereochemistry , inorganic chemistry , organic chemistry , catalysis , biochemistry , receptor
We report here a new synthetic route to highly‐substituted tetraazamacrocycles. Raney nickel hydrogenation of macrocyclic phenylenediamine–acetylacetone condensation products gives cyclams in high yield with complexes all‐cis stereoselectivity. The extensive C ‐substitution of the cyclam 2a changes its ligand properties markedly. The X‐ray structure analyses of Ni II , Cu II , and Zn II complexes of 2a reveals a deviation of the metal ion coordination geometry from the usual square‐planar arrangement. This may account for the differences in the redox properties of the Ni II and Cu II complexes of 2a leads to more positive oxidation and reduction potentials compared to the analogous unsubstituted cyclam complexes. While the binding constant between Zn(ClO 4 ) 2 and 2a is lower by a factor of 10 5 compared to cyclam, the subsequent binding of uridine to the zinc‐cyclam complexes in methanol/water is slightly stronger in the case of 2a · Zn(ClO 4 ) 2 ].