Graphitic oxidative cleavage reactions

One final example of C-CN cleavage has appeared that involves rhodium instead of nickel [58]. Reduction of [Rh(dippe)Cl]2 with potassium graphite led to a species assigned as [Rh(dippe)]2K2(THF)2. Here the rhodium is formally in the — 1 oxidation state, so the complex is isoelectronic with [Ni(dippe)]. The complex reacts with benzonitrile to give the C-CN cleavage product, just as seen with nickel. Use of labeled substrate Ph CN gives a product that can be readily characterized as K [Rh (dippe)(Ph)( CN)] using H, C, and P NMR spectroscopy. Further study of this reaction was not possible, as sources of protons readily lead to the known complex [(dippe)Rh]2(p-H)(p-N=CHPh) reported by Fryzuk [59]. 

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