Scandium Arene Inverted-Sandwich Complexes Supported by a Ferrocene Diamide Ligand

摘要

The synthesis and characterization of the first scandium arene inverted-sandwich complexes supported by a ferrocene diamide ligand (NN~(fc) are reported. Through the use of (NN c)ScI(THF)2 as a precursor and potassium graphite (KC_8) as a reducing agent, the naphthalene and anthracene complexes [(NN ~(tc))Sc]_2(μ-C_(10)H_8) and [(NN~(fc)Sc]_2(μ-C_(14)H_(10)), respectively, were synthesized and isolated in moderate to high yields. Both molecular structures feature an inverted-sandwich geometry and exhibit short Fe—Sc distances. DFT calculations were employed to gain understanding of the electronic structures of these new scandium arene complexes. A variable-temperature NMR spectroscopic study of [(NN~(fc))Sc]_2CM-C_(14)H~(10)) indicated that two different structures are accessible in solution. Reactivity studies showed that the naphthalene complex [(NN~(fc))Sc]_2(M-C_(10)H_8) can be converted to the corresponding anthracene species[(NN~(fc))Sc]_2(M-C_(10)H_8) and that [(NN~(fc))Sc]_2(M-C_(10)H_8) can act as either a reductant or a proton acceptor. The reaction of[(NN~(fc))Sc]_2(M-C_(10)H_8) with excess pyridine led to a rare example of C—C bond formation between two pyridine rings at the para position.