Formation and structural properties of 1,1′,2,2′-tetra(tert-butyl-carbamoyl)-ferrocene and -ruthenocene

摘要

Sodium cyclopentadienide adds two molar equivalents of tert-butyliscocyanate to yield the the 1,2-bis(N-tert-butylcarbamoyl)cyclopentadienide reagent 1. This reacts with RuCl_2(PPh_3)_4 3 in a 2:1 stoichiometry to yield the metallocene [#eta#~5-C_5H_3(CONHCMe_3)_2]_2Ru 5. Complex 5 was characteried by an X-ray crystal structure analysis. It shows a near to eclipsed C_2-symmetric metallocene conformation with the carboxamide subsituents pairwise concented by intramolecular hydrogen bridges between-CONHR groups attached to different Cp ligands. The intermediate of the substitution reaction sequence, the complex [#eta#~5-C_5H_3(CONHCMe_3)_2]RuCl(PPh_3)_2 4, was also isolated and characterized by X-ray diffraction. Treatment of 1 with FeCl_2(2:1) yields 1,1′,2,2′-tetra(N-tert-butylcarbamoyl)ferrocene 6. The X-ray crystal structure analysis of 6 features a. staggered C_i metallocene conformation.