title: 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 substituents.
abstract: 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 Co-N 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 Jahn-Teller 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 Mössbauer 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.
authors: A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, 119991, Moscow, Russian Federation. voloshin@ineos.ac.ru
authors: Y Z
authors: YZ
authors: Voloshin
authors: I G
authors: IG
authors: Belaya
authors: A S
authors: AS
authors: Belov
authors: V E
authors: VE
authors: Platonov
authors: A M
authors: AM
authors: Maksimov
authors: A V
authors: AV
authors: Vologzhanina
authors: Z A
authors: ZA
authors: Starikova
authors: A V
authors: AV
authors: Dolganov
authors: V V
authors: VV
authors: Novikov
authors: Y N
authors: YN
authors: Bubnov