Selective metal-cation recognition by [2.2]ferrocenophanes: the cases of zinc- and lithium-sensing.
The synthesis, electrochemical, optical, and cation-sensing properties of [2.2]ferrocenophanes, in which the two ferrocene subunits are linked through two aldiminic or iminophosphorane moieties, are reported. The new compounds show remarkably selective cation-sensing properties due to the presence of redox-active units (ferrocene) and aza-unsaturated functionalities that are able to act as putative cation-binding sites. In this structural motif, the aldimine groups act as a highly selective binding site for Zn(2+) cations, whereas the iminophosphorane bridges display an unusually strong binding affinity towards Li(+) cations, which could be explained by an additional LiFe interaction. The X-ray structure of the complex 4Li(+) as well as detailed NMR spectroscopic studies, both in solution and in the solid state, support this assessment. Experimental data and conclusions about the cation-sensing capabilities of this family of compounds are supported by DFT calculations.
Otón
Francisco
F
Universidad de Murcia, Departamento de Química Orgánica, Facultad de Química, Campus de Espinardo, 30100 Murcia, Spain.
Ratera
Imma
I
Espinosa
Arturo
A
Wurtz
Klaus
K
Parella
Teodor
T
Tárraga
Alberto
A
Veciana
Jaume
J
Molina
Pedro
P
D002412:Cations / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry*
D002412:Cations; D005296:Ferrous Compounds; D008670:Metals; D008094:Lithium; D015032:Zinc