Mononuclear ferrocenophane structural motifs with two thiourea arms acting as a dual binding site for anions and cations.
The synthesis of a new type of mononuclear ferrocenophane-based thiourea, in which the ferrocene moiety is simultaneously attached to two thiourea groups directly from 1,1'-bis(isothiocyanato)ferrocene, is reported. These nitrogen-rich structural motifs show remarkable ion-sensing properties because of the presence of the redox active ferrocene unit and the thiourea bridges, which unexpectedly act as a dual binding site for anions and metal ions. They display a selective downfield shift of the thiourea protons and a remarkable cathodic shift of the ferrocene/ferrocenium redox couple with F(-), AcO(-), H(2)PO(4)(-), and HP(2)O(7)(3-) anions, whereas the selective recognition of Hg(2+) metal cations is achieved either by electrochemical or by spectral measurements. The preferred binding modes are proposed for the most representative complexes by means of density functional theory based theoretical calculations showing the Janus-like faces of the receptor.
Otón
Francisco
F
Departamento de Química Orgánica, Facultad de Química, Campus de Espinardo, Universidad de Murcia, E-30100 Murcia, Spain.
Espinosa
Arturo
A
Tárraga
Alberto
A
Ratera
Imma
I
Wurst
Klaus
K
Veciana
Jaime
J
Molina
Pedro
P
D000838:Anions / Q000737:chemistry; D001665:Binding Sites; D055664:Electrochemical Techniques; D005296:Ferrous Compounds / Q000737:chemistry*; D000075163:Metallocenes; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013890:Thiourea / Q000737:chemistry
D000838:Anions; D005296:Ferrous Compounds; D000075163:Metallocenes; C064804:ferrocenium; D013890:Thiourea; C004998:ferrocene