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pH‐Driven Cu 2+ Translocation in Ferrocene‐Containing Ligands
Author(s) -
Pallavicini Piersandro,
Dacarro Giacomo,
Mangano Carlo,
Patroni Stefano,
Taglietti Angelo,
Zai Robertino
Publication year - 2006
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600607
Subject(s) - chemistry , protonation , ferrocene , titration , potentiometric titration , coordination complex , electrochemistry , inorganic chemistry , rhenium , stability constants of complexes , bioinorganic chemistry , crystallography , stereochemistry , medicinal chemistry , metal , ion , organic chemistry , electrode
The ligands L1 H 4 , L2 H 2 , and L 3H 4 have been synthesized, featuring two, one, and two ferrocene‐functionalized diamino‐diamido compartments, respectively. The coordination chemistry of the ligands towards Cu 2+ has been fully characterized by means of potentiometric and spectrophotometric titrations, which allowed us to determine the protonation constants of the ligands, the formation constants of their complexes, and their coordination geometry. L1 H 4 and L2 H 2 feature additional diaminopyridine and bis(aminoquinoline) binding sites, respectively, and are capable of the pH‐driven translocation of two and one Cu 2+ cations, respectively. Electrochemical experiments (CV) coupled with pH‐metric titrations demonstrate that while the coordination of Cu 2+ to the compartments more distant from ferrocene (Fc), i.e. diaminopyridine in L1 H 4 and bis(aminoquinoline) in L2 H 2 leaves the oxidation potential of Fc unchanged, the translocation of the Cu 2+ cation(s) inside the diamino‐diamido compartment(s) is signaled by a peculiar lowering of the Fc oxidation potential. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)