title: Unusual nitrile-nitrile and nitrile-alkyne coupling of Fc-C≡N and FC-C≡C-C≡N.
abstract: The reactions of the Group 4 metallocene alkyne complexes, [Cp*2M(η2-Me3SiC2SiMe3)] (1 a: M=Ti, 1 b: M=Zr, Cp*=η5-pentamethylcyclopentadienyl), with the ferrocenyl nitriles, Fc-CN and Fc-C≡C-C≡N (Fc=Fe(η5-C5H5)(η5-C5H4)), is described. In case of Fc-C≡N an unusual nitrile–nitrile C-C homocoupling was observed and 1-metalla-2,5-diaza-cyclopenta-2,4-dienes (3 a, b) were obtained. As the first step of the reaction with 1 b, the nitrile was coordinated to give [Cp*2Zr(η2-Me3SiC2SiMe3)(N≡C-Fc)] (2 b). The reactions with the 3-ferrocenyl-2-propyne-nitrile FcC≡C-C≡N lead to an alkyne–nitrile C-C coupling of two substrates and the formation of 1-metalla-2-aza-cyclopenta-2,4-dienes (4 a, b). For M=Zr, the compound is stabilized by dimerization as evidenced by single-crystal X-ray structure analysis. The electrochemical behavior of 3 a, b and 4 a, b was investigated, showing decomposition after oxidation, leading to different redox-active products.
authors.forename: Lisanne
authors.initials: L
authors.lastname: Becker
authors.forename: Frank
authors.initials: F
authors.lastname: Strehler
authors.forename: Marcus
authors.initials: M
authors.lastname: Korb
authors.forename: Perdita
authors.initials: P
authors.lastname: Arndt
authors.forename: Anke
authors.initials: A
authors.lastname: Spannenberg
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Baumann
authors.forename: Heinrich
authors.initials: H
authors.lastname: Lang
authors.forename: Uwe
authors.initials: U
authors.lastname: Rosenthal