Reversible rearrangements of Cu(II) cage complexes: solvent and anion influences

Bernhardt, Paul V., Font, Helena, Gallego, Carlos, Martinez, Manuel and Rodriguez, Carlos (2012) Reversible rearrangements of Cu(II) cage complexes: solvent and anion influences. Inorganic Chemistry, 51 22: 12372-12379. doi:10.1021/ic301696v


Author Bernhardt, Paul V.
Font, Helena
Gallego, Carlos
Martinez, Manuel
Rodriguez, Carlos
Title Reversible rearrangements of Cu(II) cage complexes: solvent and anion influences
Journal name Inorganic Chemistry   Check publisher's open access policy
ISSN 0020-1669
1520-510X
Publication date 2012-11-01
Sub-type Article (original research)
DOI 10.1021/ic301696v
Volume 51
Issue 22
Start page 12372
End page 12379
Total pages 8
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2013
Language eng
Formatted abstract
The macrobicyclic mixed donor cage ligand AMME-N3S3sar (1-methyl-8-amino-3,13,16-trithia-6,10,19-triazabicyclo[6.6.6]eicosane) is capable of binding to Cu(II) as either a hexadentate (N3S3) or tetradentate (N2S2) ligand. The “Cu-in” (hexadentate)/“Cu-out” (tetradendate) equilibrium for the {Cu(AMME-N3S3sar)}2+ units is strongly influenced by both solvent (DMSO, MeCN, and water) and halide ions (Br– and Cl–). We have established a crucial role of the solvent in these processes through the formation of intermediate solvato complexes, which are substituted by incoming halide ions triggering a final isomerization reaction. Surprisingly, for reactions carried out in the usually strongly coordinating solvent water, the completely encapsulated N3S3-bound “Cu-in” form is dominant. Furthermore, the small amounts of the “Cu-out” form present in equilibrated DMSO or MeCN solutions revert entirely to the “Cu-in” form in aqueous media, thus preventing reaction with halide anions which otherwise lead to partial or even complete decomposition of the complex. From the kinetic, electrochemical, and EPR results, the existence of an outer-sphere H-bonded network of water molecules interacting with the complex inhibits egress of the Cu(II) ion from the cage ligand. This is extremely relevant in view of outer sphere interactions present in strongly hydrogen bonding solvents and their effects on Cu(II) complexation.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Chemistry and Molecular Biosciences
 
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Created: Fri, 23 Nov 2012, 19:56:16 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences