title: Chloride ion-aided self-assembly of pseudoclathrochelate metal tris-pyrazoloximates.
abstract: Chloride ion-aided one-pot template self-assembly of a mixed pyrazoloxime ligand with phenylboronic acid on a corresponding metal(II) ion as a matrix afforded the first boron-capped zinc, cobalt, iron, and manganese pseudoclathrochelate tris-pyrazoloximates. The presence of a pseudocross-linking hydrogen-bonded chloride ion is critical for their formation, as the same chloride-capped complexes were isolated even in the presence of large excesses of bromide and iodide ions. As revealed by X-ray diffraction, all complexes are capped with a chloride ion via three N-H···Cl hydrogen bonds that stabilize their pseudomacrobicyclic frameworks. The MN6 coordination polyhedra possess a distorted trigonal prismatic geometry, with the distortion angles φ between their nonequivalent N3 bases of approximately 0°. Temperature dependences of the effective magnetic moment for the paramagnetic complexes showed the encapsulated metal(II) ions to be in a high-spin state in the temperature range of 2-300 K. In the case of the iron(II) pseudoclathrochelate, density functional theory (DFT) and time-dependent DFT calculations were used to assess its spin state as well as the (57)Fe Mössbauer and UV-vis-NIR parameters. Cyclic voltammetry studies performed for these pseudomacrobicyclic complexes showed them to undergo irreversible or quasi-reversible metal-localized oxidations and reductions. As no changes are observed in the presence of a substantial excess of bromide ion, no anion-exchange reaction occurs, and thus the pseudoclathrochelates have a high affinity toward chloride anions in solution.
authors.affiliation: Vernadskii Institute of General and Inorganic Chemistry of the National Academy of Sciences of Ukraine , 03680 Kyiv, Ukraine.
authors.forename: Oleg A
authors.initials: OA
authors.lastname: Varzatskii
authors.forename: Larysa V
authors.initials: LV
authors.lastname: Penkova
authors.forename: Svitlana V
authors.initials: SV
authors.lastname: Kats
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Dolganov
authors.forename: Anna V
authors.initials: AV
authors.lastname: Vologzhanina
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Pavlov
authors.forename: Valentin V
authors.initials: VV
authors.lastname: Novikov
authors.forename: Artem S
authors.initials: AS
authors.lastname: Bogomyakov
authors.forename: Victor N
authors.initials: VN
authors.lastname: Nemykin
authors.forename: Yan Z
authors.initials: YZ
authors.lastname: Voloshin