Low-Valent Iron(I) Amido Olefin Complexes as Promotors for Dehydrogenation Reactions

Fe-I compounds including hydrogenases show remarkable properties and reactivities. Several iron(I) complexes have been established in stoichiometric reactions as model compounds for N-2 or CO2 activation. The development of well-defined iron(I) complexes for catalytic transformations remains a challenge. The few examples include cross-coupling reactions, hydrogenations of terminal olefins, and azide functionalizations. Here the syntheses and properties of bimetallic complexes [MFeI(trop(2)dae)(solv)] (M= Na, solv= 3thf; M= Li, solv= 2Et(2)O; trop= 5H-dibenzo[a, d] cyclo-hepten-5-yl, dae=(N-CH2-CH2-N) with a d(7) Fe low-spin valence-electron configuration are reported. Both compounds promote the dehydrogenation of N, N-dimethylaminoborane, and the former is a precatalyst for the dehydrogenative alcoholysis of silanes. No indications for heterogeneous catalyses were found. High activities and complete conversions were observed particularly with [NaFeI(trop(2)dae)(thf)(3)].