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Metal complexes with macrocyclic ligands. Part XIX . Synthesis and Cu 2+ ‐complexes of a series of 12‐, 14‐ and 16‐membered cis ‐ and trans ‐N 2 S 2 ‐macrocycles
Author(s) -
Siegfried Liselotte,
Kaden Thomas A.
Publication year - 1984
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.19840670105
Subject(s) - chemistry , heteroatom , cyclic voltammetry , electron paramagnetic resonance , electrochemistry , transition metal , crystallography , aqueous solution , metal , copper , absorption spectroscopy , stereochemistry , electrode , alkyl , organic chemistry , nuclear magnetic resonance , physics , quantum mechanics , catalysis
A series of 12‐, 14‐, and 16‐membered N 2 S 2 ‐macrocycles ( 9–11 and 19–21 ) with cis and trans ‐arrangement of the heteroatoms have been synthesized by high‐dilution cyclization and subsequent reduction of the amides with B 2 H 6 . With these ligands the corresponding Cu 2+ ‐complexes were prepared and their UV/VIS spectra, their electrochemistry and their EPR properties have been studied. Generally three absorption bands at 270–320 nm, 330–370 nm and 530–620 nm can be observed in aqueous solution and these have been assigned to the N→Cu 2+ and S→Cu 2+ charge‐transfer bands and to the d‐d* transition, respectively. The cyclic voltammetry in CH 3 CN shows in all cases a reversible or quasi‐reversible Cu 2+ /Cu + ‐transition at potentials of 10–480 mV against SHE. The values of g ‖ and A ‖ obtained from EPR spectra indicate that the geometry of the Cu 2+ ‐complex of the 14‐membered cis ‐N 2 S 2 ‐macrocycle is less distorted than that of the other complexes.