Organochromium cations

Figure 1. Plot of AGM8 for the homolysis of organochromium cations vs. AG for the homolysis of the correspondingly substituted ethanes (with OH replaced by CHS). Key for organochromium ions O, CrC(RfR )OH2+ , CrCfRJt fOR"2 V, CrCH(CHs)t2 and +, CrCHJPh2. ...

Fractional orders such as 3/2 often hint at a chain mechanism. The autoxidation of (H20)5CrCH(CH3) + leads to a number of products. Log (inititd rate) vs log (initial concentration of organochromium cation) plots give a 3/2 slope. The rate is independent of [H+] and [O2] and the rate law is therefore... 

Chromium.—Organochromium cations [CrR(H20)5] + (R=alkyl or substituted benzyl group) react with Hg + forming RHg+ and [CrCHaO) ] while with MeHg+, MeHgR and [Cr(H20) ] + are formed. Both types of reaction follow a second-order rate law (1) (M = Hg + or MeHg+) and with the exception of MeHg++... 

The [Cr(0H2)6]2+/H202 reaction is important in the synthesis of air-stable cationic organochromium(III) complexes (see Section III,B), as the initially produced OH radicals react rapidly with added organic substrates to form alkyl radicals, which, in turn, react with [Cr(OH2)6]2+ (15), (16). 

Organochromium species containing tt-bonded ligands were first prepared by Hein as early as 1919, but were not definitively characterized for another 35 years. Hein reported on the reaction of PhMgBr with CrCb to give Chromorganoverbindungen this synthesis was reproduced by Zeiss and Tsutsui in 1954, at which time they identified the products as bis(arene)chromium cations. Shortly thereafter, Fischer and Haftier published their route to neutral bis(benzene)chromium. This early work has been chronicled, most recently by Seyferth. ... 

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