Oxidatively Induced Reductive Elimination from a Chromium(III) Bis(aryl) Complex

The previously reported high-spin Cr(II) compounds CpCr(C6H4CH2NMe2) (1) and CpCr[C(Ph)C(Ph)C6H4CH2NMe2] (2) were investigated as precursors to CpCr(III) complexes. Single-electron oxidation of 1 was used to prepare CpCr(C6H4CH2NMe2)(X) for X = I (3), OTs (4), O2CPh (5), OCMe2Ph (6), SPh (7). Similarly, CpCr[C(Ph)C(Ph)C6H4CH2NMe2](X) for X = I (8), SPh (9) were obtained from 2. Reactions of 4 with PhCH2MgCl or Mg(C6H4Me)(2) reagents gave the Cr(III) benzyl (10) and p-tolyl (11) complexes, respectively. The corresponding reaction of 4 with Mg(CH2CMe3)(2) led to isolation of 12, a bimetallic complex with a bridging neopentylidene group. While the reaction of 7 or 10 with AgOTs gave Cr(III) tosylate complex 4, the reaction of 11 and AgOTs led to the product of reductive elimination. The structures of 1, 2, 6-8, 11, and 12 were elucidated using single-crystal X-ray diffraction.