Does a Reinforced Kinetic Macrocyclic Effect Exist? The Demetallation in Strong Acid of Copper(II) Complexes with Open and Cyclic Tetramines Containing a Piperazine Fragment
- 24 June 2004
- journal article
- Published by Wiley in Chemistry – A European Journal
- Vol. 10 (13) , 3209-3216
- https://doi.org/10.1002/chem.200305717
Abstract
The demetallation in acidic solution of the CuII complexes with open‐chain and cyclic tetramines containing a piperazine unit (2 and 3) has been investigated in terms of its kinetic aspects and compared with the behaviour of unsubstituted counterparts (tetramines 1 and 4). The presence of the piperazine fragment slows demetallation of the open‐chain‐ligand complex owing to the activation barrier associated with the conformational change from boat‐to‐half‐boat; however, it does not affect the demetallation of the macrocyclic complex, which involves the spontaneous boat‐to‐twist conformational change. Thus, lateral reinforcement of a cyclam‐like ligand does not add any further contribution to the typical inertness in demetallation of macrocyclic complexes.Keywords
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