title: Decacyclene as complexation manifold: synthesis, structure and properties of its Fe2 and Fe4 slipped triple-decker complexes.
abstract: Reaction of [(eta(5)-Me4EtC5)Fe(II)Cl(tmeda)] (tmeda = N,N,N'N'-tetramethylethylenediamine) with a polyanion solution of decacyclene (1) results in the formation of the triple-deckers [{(eta(5)-Me4EtC5)Fe}2-mu2-(eta(6):eta(6)-decacyclene)] (3) and [{(eta(5)-Me4EtC5)Fe}4-mu4-(eta(6):eta(6):eta(6):eta(6)-decacyclene)] (4). Metal complexation in 3 and 4 occurs on opposite faces of the pi perimeter in an alternating mode. The decacyclene ring adopts a gently twisted molecular propeller geometry with twofold crystallographic symmetry (C2). Complex 4 crystallizes in the chiral space group C222(1); the investigated crystal only contains decacyclene rings with M chirality. The handedness can be assigned unambiguously to the presence of the iron atoms. Cyclovoltammetric studies revealed quasireversible behavior of the redox events and a strong interaction of the Fe atoms in 3 and 4, exemplified by potential differences deltaE of 660 and 770(780) mV between the first and the second individual oxidation processes. This corresponds to a high degree of metal-metal interaction for 3 and 4. The successful syntheses of 3 and 4 together with earlier results from our laboratory proves that all five- and six-membered pi subunit sets of 1 are prone to metal complexation. A clear site preference in 1 towards the complexation of [Cp(R)]iron, -cobalt, and -nickel fragments exists.
authors.affiliation: Fachbereich Chemie, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, TU Darmstadt, Petersenstrasse 18, 64287 Darmstadt, Germany. joerg.schneider@ac.chemie.tu-darmstadt.de
authors.forename: Jörg J
authors.initials: JJ
authors.lastname: Schneider
authors.forename: Dirk
authors.initials: D
authors.lastname: Spickermann
authors.forename: Christian W
authors.initials: CW
authors.lastname: Lehmann
authors.forename: Jörg
authors.initials: J
authors.lastname: Magull
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Krüger
authors.forename: Jürgen
authors.initials: J
authors.lastname: Ensling
authors.forename: Philipp
authors.initials: P
authors.lastname: Gütlich