Migratory Insertion and Reductive Coupling of Tetraarylruthenium(IV) Complexes

• Published in: Organometallics 2014-09, Vol.33 (17), p.4497-4502
• Main Authors: So, Shiu-Chun, Cheung, Wai-Man, Wang, Guo-Cang, Kwan Huang, Enrique, Lau, Man-Kit, Zhang, Qian-Feng, Sung, Herman H.-Y, Williams, Ian D, Leung, Wa-Hung
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om500707e

Tetraarylruthenium(IV) complexes have been synthesized and their migratory insertion, reductive coupling, and bromination reactions investigated. Treatment of [Ru(acac)3] (acac– = acetylacetonate) with RMgBr, followed by column chromatography in air afforded the tetraaryl complexes [RuR4] (R = 2,5-dimethylphenyl (R1); 4-methoxy-2-methylphenyl (R2)). Oxidation of [RuR2 4] with AgBF4 gave the Ru(V) complex [RuVR2 4](BF4), which has a measured μeff of 1.8 μB. [RuR4] and can catalyze the oxidation of methyl p-tolyl sulfide with PhIO. Reaction of [RuR2 4] with PhICl2 led to C–C reductive coupling and the formation of the Ru(II) η6-biaryl complex [(η6-R2-R2)RuCl2]2 (1). Treatment of [RuR1 4] with excess NO gave the tetranuclear Ru(II) aryl-N-nitrosohydroxylaminato complex [RuR1(N){κ2-O,O′-ON(R1)NO}(μ-NO2)]4 (2). Bromination of [RuR1 4] with N-bromosuccinimide resulted in formation of [RuR′4] (R′ = 4-bromo-2,5-dimethylphenyl) (3). The crystal structures of [RuR2 4], [RuR2 4](BF4), and 1–3 have been determined.