Formation of the second superhydrophobic shell around an encapsulated metal ion: synthesis, X-ray structure and electrochemical study of the clathrochelate and bis-clathrochelate iron(ii) and cobalt(ii, iii) dioximates with ribbed perfluoroarylsulfide substituentsCCDC reference numbers 797962797966. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c1dt10500k

• Main Authors: Voloshin, Y. Z, Belaya (Makarenko), I. G, Belov, A. S, Platonov, V. E, Maksimov, A. M, Vologzhanina, A. V, Starikova, Z. A, Dolganov, A. V, Novikov, V. V, Bubnov, Y. N
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c1dt10500k

The nucleophilic substitution of six chlorine atoms of the n-butylboron-capped clathrochelate iron and cobalt( ii ) precursors with perfluoroarylthiolate anions afforded the hexaperfluoroarylsulfide macrobicyclic iron and cobalt( ii ) tris-dioximates. The complexes obtained are soluble in aromatic and aliphatic hydrocarbons as well as in polar aprotonic solvents due to the presence of the superhydrophobic fluorine-containing molecular periphery. As it follows from the X-ray data for five iron and cobalt mono- and bis-clathrochelates, the geometry of their macrobicyclic frameworks is affected by both the nature of an encapsulated metal ion and that of the ribbed substituents. Bis-capping fragment Co II O 6 of the Co III Co II Co III bis-clathrochelate possesses a trigonal antiprismatic geometry, all the Co II N 6 coordination polyhedra are trigonal-prismatic, and those of the encapsulated iron( ii ) and cobalt( iii ) ions are intermediate between them. The wide range of CoN distances as well as the significant shifts of the encapsulated cobalt( ii ) ions from the centres of their N 6 -coordination polyhedra were explained by the JahnTeller distortion. The EPR and magnetometry data are also characteristic of the low-spin cobalt( ii ) complexes with this distortion. The parameters of the 57 Fe Mssbauer spectra of the iron macrobicycles are characteristic of the low-spin iron( ii ) complexes. The cyclic voltammograms (CVs) for the complexes studied contain the one-electron oxidation and reduction waves assigned to metal-centered redox-processes. The Fe 2+/3+ and Co 2+/3+ oxidations are quasi-reversible or irreversible. The anionic clathrochelate species resulting from the reversible Co 2+/+ reductions are stable on the CV time scale, whereas their iron( i )-containing analogs are unstable. The iron and cobalt( ii ) clathrochelates with six perfluoroarylsulfide substituents were obtained and characterized.