title: Multinuclear NMR Study of the Structure and Intramolecular Dynamics of (eta(2)-Acetone phenylhydrazonato)tetrafluorooxotungsten(VI).
abstract: Using one- and two-dimensional techniques of (1)H, (13)C, (15)N, and (19)F NMR spectroscopy, it was proved that acetone phenylhydrazone (H-aph) acts as a two-center N,N-donor ligand in the complex [WOF(4)(aph)](-). As a result of the coordination to tungsten, the ligand conformation changes from E to Z, and at the same time the phenyl ring is turned out of the >N-N=C< plane. At low temperatures (-30 degrees C), the equatorial plane of the pentagonal-bipyramidal tungsten polyhedron comprises two donor nitrogen atoms of hydrazone and three fluoro ligands. At elevated temperatures, stereoisomeric interconversion caused by hindered intramolecular rotation of the aph(-) ligand occurs. The mechanism of this process was elucidated on the basis of the dynamic effects in (19)F spectra and line-shape analysis of the trans-CH(3) resonance in (13)C spectra split due to direct "through-space" coupling with the proximate fluoro ligand.
authors.affiliation: Magnetic Resonance Unit, Derer Hospital, 833 05 Bratislava, Slovakia.
authors.forename: Sergei G.
authors.initials: SG
authors.lastname: Sakharov
authors.forename: Yuri A.
authors.initials: YA
authors.lastname: Buslaev
authors.forename: Ivan
authors.initials: I
authors.lastname: Tkác