Copper(II) chemistry of the functionalized macrocycle cyclam tetrapropionic acid

The CuII complex of H4TETP (H4TETP = 1,4,8,11-tetraazatetradecane-1,4,8,11-tetrapropionic acid) is five-coordinate with a distorted square-pyramidal structure (τ = 0.45; i.e. the geometry is nearly half-way between square-pyramidal and trigonal-bipyramidal) and a relatively long Cu-N and a short Cu-...

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Bibliographic Details
Main Authors: Comba, Peter (Author) , Jakob, Maik (Author) , Morgen, Michael (Author)
Format: Article (Journal)
Language:English
Published: 2013
In: Dalton transactions
Year: 2012, Volume: 42, Issue: 17, Pages: 6142-6148
ISSN:1477-9234
DOI:10.1039/C2DT32356G
Online Access:Verlag, Volltext: http://dx.doi.org/10.1039/C2DT32356G
Verlag, Volltext: https://pubs.rsc.org/en/content/articlelanding/2013/dt/c2dt32356g
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Author Notes:Peter Comba, Franziska Emmerling, Maik Jakob, Werner Kraus, Manja Kubeil, Michael Morgen, Jens Pietzsch and Holger Stephan
Description
Summary:The CuII complex of H4TETP (H4TETP = 1,4,8,11-tetraazatetradecane-1,4,8,11-tetrapropionic acid) is five-coordinate with a distorted square-pyramidal structure (τ = 0.45; i.e. the geometry is nearly half-way between square-pyramidal and trigonal-bipyramidal) and a relatively long Cu-N and a short Cu-O bond; the comparison between powder and solution electronic spectroscopy, the frozen solution EPR spectrum and ligand-field-based calculations (angular overlap model, AOM) indicate that the solution and solid state structures are very similar, i.e. the complex has a relatively low “in-plane” and a significant axial ligand field with a dx2−y2 ground state. The ligand-enforced structure is therefore shown to lead to a partially quenched Jahn-Teller distortion and to a relatively low complex stability, lower than with the corresponding acetate-derived ligand H4TETA. This is confirmed by potentiometric titration and by the biodistribution with 64Cu-labeled ligands which show that the uptake in the liver is significantly increased with the H4TETP-based system.
Item Description: First published 27 Nov 2012
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Physical Description:Online Resource
ISSN:1477-9234
DOI:10.1039/C2DT32356G