Syntheses, structures and electrochemistry of some 1-(η2-allylamino)-1-ferrocenylcarbene complexes of chromium(0), molybdenum(0) and tungsten(0): Part 13: The chemistry of metallacyclic alkenylcarbene complexes

The metallacyclic complexes (OC)4Mdouble bond; length as m-dashC(η2-NHCH2CHdouble bond; length as m-dashCHX)Fc (4; X = H) and (5; X = CH2OH) [M = Cr: a; Mo: b; W: c; Fc = ferrocenyl = CpFe(C5H4)] were obtained in good yields upon photo-decarbonylation of the bimetallic allylaminocarbene complexes (OC)5Mdouble bond; length as m-dashC(NHCH2CHdouble bond; length as m-dashCHX)Fc (2; X = H)/(3; X = CH2OH). At room temperature complexes 2/3 exist as mixtures of E- and predominantly Z-isomers with regard to the C–N bond. The molecular structures of 4b and 4c were determined by X-ray diffraction analyses. The intermetallic communicative effects and the interplay of Fc and η2-alkene moieties of 4a and 4b were assessed by cyclovoltammetry. All complexes were also characterized in solution by one- and two-dimensional NMR spectroscopy (1H, 13C, 1H NOE, 1H/1H COSY, 13C/1H HETCOR).