title: A paramagnetic heterobimetallic polymer: synthesis, reactivity, and ring-opening polymerization of tin-bridged homo- and heteroleptic vanadoarenophanes.
abstract: The synthesis of the first tin-bridged bis(benzene) vanadium and trovacene sandwich compounds and the investigation of their oxidative addition and insertion behavior are reported. The vanadoarenophanes and the corresponding platinum insertion products were fully characterized including electrochemical and electron paramagnetic resonance (EPR) measurements. Controllable ring-opening polymerization of the heteroleptic tin-bridged [1]trovacenophane using Karstedt's catalyst yields a high molecular weight polymer (up to M(n) = 89 200 g·mol(-1)) composed of d(5)-vanadium metal centers in the main chain, making it a rare example of a spin-carrying macromolecule. Magnetic susceptibility measurements (SQUID) confirm the paramagnetic scaffold with repeating S = 1/2 centers in the main chain and suggest antiferromagnetic interactions between adjacent spin sites (Weiss constant Θ = -2.9 K).
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg , Am Hubland, 97074 Würzburg, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Braunschweig
authors.forename: Alexander
authors.initials: A
authors.lastname: Damme
authors.forename: Serhiy
authors.initials: S
authors.lastname: Demeshko
authors.forename: Klaus
authors.initials: K
authors.lastname: Dück
authors.forename: Thomas
authors.initials: T
authors.lastname: Kramer
authors.forename: Ivo
authors.initials: I
authors.lastname: Krummenacher
authors.forename: Franc
authors.initials: F
authors.lastname: Meyer
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Radacki
authors.forename: Sascha
authors.initials: S
authors.lastname: Stellwag-Konertz
authors.forename: George R
authors.initials: GR
authors.lastname: Whittell