Rhodium complexes tetracyanoethylene

Rhodium and Iridium. Tetracyanoethylene, TCNE, undergoes reversible addition to rhodium complexes as in equation (45), where X=C1, L=P(4-MeOC H4)8,... 

As previously shown in equation (52), the Rh -peroxo complex (69) selectively oxidizes terminal alkenes with methyl ketones. In contrast, the complex [Rh02(dppe)2] C104 was found to be inactive, illustrating that it is necessary to to be able to create a coordination site for the alkene at rhodium. Further, an Rh peroxometallacycle (76) from the reaction of (69) with tetracyanoethylene has been characterized. ... 

Intramolecular rearrangement in five-co-ordinate cobalt(i) and rhodium(i) complexes of the type [ML4((CN)2C—C(CN)2 ]+, where L represents various cyano-substituted organic ligands, are shown to be due to Berry pseudorotation, to rotation around the tetracyanoethylene double bond, and to catalysis by anions due to formation of ion pairs. 

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