title: Electronically Strongly Coupled Divinylheterocyclic-Bridged Diruthenium Complexes.
abstract: Complexes [{Ru(CO)Cl(PiPr3 )2 }2 (μ-2,5-(CH-CH)2 -(c) C4 H2 E] (E=NR; R=C6 H4 -4-NMe2 (10 a), C6 H4 -4-OMe (10 b), C6 H4 -4-Me (10 c), C6 H5 (10 d), C6 H4 -4-CO2 Et (10 e), C6 H4 -4-NO2 (10 f), C6 H3 -3,5-(CF3 )2 (10 g), CH3 (11); E=O (12), S (13)) are discussed. The solid state structures of four alkynes and two complexes are reported. (Spectro)electrochemical studies show a moderate influence of the nature of the heteroatom and the electron-donating or -withdrawing substituents R in 10 a-g on the electrochemical and spectroscopic properties. The CVs display two consecutive one-electron redox events with ΔE°'=350-495 mV. A linear relationship between ΔE°' and the σp Hammett constant for 10 a-f was found. IR, UV/Vis/NIR and EPR studies for 10(+) -13(+) confirm full charge delocalization over the {Ru}CH-CH-heterocycle-CH-CH{Ru} backbone, classifying them as Class III systems according to the Robin and Day classification. DFT-optimized structures of the neutral complexes agree well with the experimental ones and provide insight into the structural consequences of stepwise oxidations.
authors.affiliation: Faculty of Natural Sciences, Institute of Chemistry, Inorganic Chemistry, Technische Universität Chemnitz, 09107 Chemnitz (Germany).
authors.forename: Ulrike
authors.initials: U
authors.lastname: Pfaff
authors.affiliation: Faculty of Natural Sciences, Institute of Chemistry, Inorganic Chemistry, Technische Universität Chemnitz, 09107 Chemnitz (Germany).
authors.forename: Alexander
authors.initials: A
authors.lastname: Hildebrandt
authors.affiliation: Faculty of Natural Sciences, Institute of Chemistry, Inorganic Chemistry, Technische Universität Chemnitz, 09107 Chemnitz (Germany).
authors.forename: Marcus
authors.initials: M
authors.lastname: Korb
authors.affiliation: Faculty of Chemistry, Universität Konstanz, 78457 Konstanz (Germany).
authors.forename: Steffen
authors.initials: S
authors.lastname: Oßwald
authors.affiliation: Faculty of Chemistry, Universität Konstanz, 78457 Konstanz (Germany).
authors.forename: Michael
authors.initials: M
authors.lastname: Linseis
authors.affiliation: Faculty of Natural Sciences, Institute of Chemistry, Polymer Chemistry, Technische Universität Chemnitz, 09107 Chemnitz (Germany).
authors.forename: Katja
authors.initials: K
authors.lastname: Schreiter
authors.affiliation: Faculty of Natural Sciences, Institute of Chemistry, Polymer Chemistry, Technische Universität Chemnitz, 09107 Chemnitz (Germany).
authors.forename: Stefan
authors.initials: S
authors.lastname: Spange
authors.affiliation: Faculty of Chemistry, Universität Konstanz, 78457 Konstanz (Germany). rainer.winter@uni-konstanz.de.
authors.forename: Rainer F
authors.initials: RF
authors.lastname: Winter
authors.affiliation: Faculty of Natural Sciences, Institute of Chemistry, Inorganic Chemistry, Technische Universität Chemnitz, 09107 Chemnitz (Germany). heinrich.lang@chemie.tu-chemnitz.de.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Lang
keywords: 5-membered heterocycles; class III Robin and Day; density functional calculations; ruthenium; spectroelectrochemistry