Arenes hydrogen exchange

Of a number of Tj6-arene complexes subsequently tested for reactivity toward H2, i76-C6H5CH3—Ru6C(CO)14 was converted stoichiometrically at 150°C to methylcyclohexane, and the t76-C6(CH3)6Ru-i74-C6(CH3)6 complex (cf. 58) was found to be a long-lived homogeneous catalyst for arene hydrogenation (444) in contrast to the cobalt system, extensive H- D exchange occurred in the aromatic ring and in substituent methyls of xylene substrates. 

Deuterium-hydrogen exchange in (CgHg)Cr(CO)3 and (MeCgHg)Cr-(CO)3 has been shown to take place in ethanol solution in the presence of sodium ethoxide, whereas no exchange is observed in the uncom-plexed arenes 265). 

The earliest catalytic application of C-H bond activation and functionalisation is that of methane using platinum chlorides as the catalyst and oxidising reagent. The exchange of hydrogen atoms in arenes with D20 was... 

In practice, it s much simpler to use the Arrhenius or Bronsted-Lowry definition of acid and base, but you ll need to use the Lewis definition when hydrogen ions aren t being exchanged. You can pick and choose among the definitions when you re asked to identify the acid and base in a reaction. 

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