Conclusion (C5Me5) 2Sm (THF) 2 reduces azobenzeneto form both mono-and dianionic species. At both levels of reduction, complexes containing^-coordination of two adjacent nitrogen atoms can be formed. In addition, an unusual 7? 1, r) 1-Ph2N22-complex can be obtained. The complex containing the Ph2N2" monoanion is not activated for reaction with CO, but the dianion-containing complexes are reactive with CO. The product obtained from the [(C5Me5) 2Sm] 2 (^-i71: 7/1-N2Ph2) reaction shows an unusual re-organization of the multiple bonds in CO and azobenzene. This example shows that (C5Me5) 2Sm (THF) 2 can generate unusual multiple bond “metathesis" reactions with heteroatomic unsatu-rated substrates and should be considered as a possible reagent when multiple bond cleavage and activation is desirable. This system also suggests that tetrahedral intermediates may provide viable pathways for reactions of this type.

Acknowledgment. We thank the National Science Foundation for support of the research.