C–H Bond Activation by a Ruthenium(II) β‐Diketonate Complex: A Mechanistic Study

Abstract

Ruthenium(II)‐catalysed C–H bond activation of arenes containing a functional directing group depends on the ligand coordinated to ruthenium(II). In this study, 2‐phenylpyridine C–H activation catalysed by a “piano‐stool“ ruthenium(II) complex containing a fluorinated β‐diketonate ligand was examined by ESI‐MS in combination with CID experiments. [Ru(β‐diketonate)(CTPhPy)Cl]+ was identified as an active intermediate, and its collisional activation leads to C–H activation. CID analysis indicates proton transfer from the phenylpyridine to the chlorine anion, showing HCl elimination, while the β‐diketonate ligand is retained in the complex together with the activated phenylpyridine. Furthermore, DFT calculations were performed for the neutral analogue [Ru(β‐diketonate)(PhPy)Cl] to identify all ruthenium intermediates along the C–H activation reaction pathway. The results suggest that the most stable structure of [Ru(β‐diketonate)(PhPy)Cl] has pre‐activated 2‐phenylpyridine with a partly developed Ru–H bond. Further, we show that K2CO3 is not directly involved in the C–H activation step and it serves in the reaction as a base.

Anti-cancer organoruthenium(ii) complexes and their interactions with cysteine and its analogues. A mass-spectrometric study

“…Ruthenium complexes are popular in synthetic chemistry because they can catalyse important reactions, including C–H activations or C–C couplings. 1 In addition to synthetic applications, ruthenium complexes have shown interesting biological activities such as anti-cancer effects. 2,3 Therefore, the design of organometallic ruthenium complexes for possible medicinal use has become a hot research topic in recent years.…”

C–H activation and subsequent C–C bond formation in rigid alkenes catalyzed by Ru(iii) metallates

“…12 More stable RuIJII) catalysts prepared in a facile way were intensively employed in such reactions. [16][17][18] An early example of C-H activation with aryl halides was reported by Oi et al by using a RuIJII) catalyst {[RuIJp-cymene)Cl 2 ] 2 }. 19 With [RuIJp-cymene)Cl 2 ] 2 as a catalyst, synthesis of many organic compounds such as maleimides, 20 homoisoflavonoids, flavones, 21 isoquinolines, 22 and isoindolinones, 23,24 has been accomplished.…”