Abstract
The stable, crystalline N-heterocyclic diaminocarbene fc[N(CH(2)tBu)-C-N(CH(2)tBu)] (2d, fc = 1,1'-ferrocenediyl) was prepared by deprotonation of its formamidinium precursor fc[N(CH(2)tBu)-CH-N(CH(2)tBu)][BF(4)] (1d) and used for the preparation of the 16 valence electron complexes [Mo(2d)-(CO)(4)], [RhCl(2d)(cod)] (cod = 1,5-cyclooctadiene) and [RhCl(2d)(CO)(2)], 1d, 2d and [RhCl(2d)(cod)] were ...
Abstract
The stable, crystalline N-heterocyclic diaminocarbene fc[N(CH(2)tBu)-C-N(CH(2)tBu)] (2d, fc = 1,1'-ferrocenediyl) was prepared by deprotonation of its formamidinium precursor fc[N(CH(2)tBu)-CH-N(CH(2)tBu)][BF(4)] (1d) and used for the preparation of the 16 valence electron complexes [Mo(2d)-(CO)(4)], [RhCl(2d)(cod)] (cod = 1,5-cyclooctadiene) and [RhCl(2d)(CO)(2)], 1d, 2d and [RhCl(2d)(cod)] were structurally characterised by single-crystal X-ray diffraction studies. The electrochemical properties of 2d, its 2-adamantyl analogue 2c, its complex [RhCl(2d)(CO)(2)] and of the precursors 1d and 1,1'-bis(neopentylamino)ferrocene were investigated by electrochemistry. The carbenes are easily oxidised to the corresponding radical cation, whose persistent nature is unprecedented in the chemistry of N-heterocychc carbenes. The spin density is located at the Fe atom and the carbene C atom according to the results of EPR spectroscopic studies and DFT calculations. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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